1
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Murdock BE, Cen J, Squires AG, Kavanagh SR, Scanlon DO, Zhang L, Tapia-Ruiz N. Li-Site Defects Induce Formation of Li-Rich Impurity Phases: Implications for Charge Distribution and Performance of LiNi 0.5-xM xMn 1.5O 4 Cathodes (M = Fe and Mg; x = 0.05-0.2). Adv Mater 2024:e2400343. [PMID: 38640450 DOI: 10.1002/adma.202400343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/08/2024] [Indexed: 04/21/2024]
Abstract
An understanding of the structural properties that allow for optimal cathode performance, and their origin, is necessary for devising advanced cathode design strategies and accelerating the commercialisation of next-generation cathodes. High-voltage, Fe- and Mg-substituted LiNi0.5Mn1.5O4 cathodes offer a low-cost and cobalt-free, yet energy-dense alternative to commercial cathodes. In this work, we explore the effect of substituents on several important structure properties including Ni/Mn ordering, charge distribution and extrinsic defects. In the cation-disordered samples studied, we observe a correlation between increased Fe/Mg substitution, Li-site defects and Li-rich impurity phase formation - the concentrations of which are greater for Mg-substituted samples. We attribute this to the lower formation energy of MgLi defects when compared to FeLi defects. Li-site defect-induced impurity phases consequently alter the charge distribution of the system, resulting in increased [Mn3+] with Fe/Mg substitution. In addition to impurity phases, other charge compensators were also investigated to explain the origin of Mn3+ (extrinsic defects, [Ni3+], oxygen vacancies and intrinsic off-stoichiometry), although their effects were found to be negligible. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Beth E Murdock
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, OX11 0RA, UK
| | - Jiayi Cen
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, OX11 0RA, UK
- Department of Chemistry and Thomas Young Centre, University College London, London, WC1H 0AJ, UK
| | - Alexander G Squires
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, OX11 0RA, UK
- School of Chemistry, University of Birmingham, Birmingham, B15 2TT, UK
| | - Seán R Kavanagh
- Department of Materials and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
| | - David O Scanlon
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, OX11 0RA, UK
- School of Chemistry, University of Birmingham, Birmingham, B15 2TT, UK
| | - Li Zhang
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, OX11 0RA, UK
| | - Nuria Tapia-Ruiz
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, OX11 0RA, UK
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2
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Li K, Willis J, Kavanagh SR, Scanlon DO. Computational Prediction of an Antimony-Based n-Type Transparent Conducting Oxide: F-Doped Sb 2O 5. Chem Mater 2024; 36:2907-2916. [PMID: 38558913 PMCID: PMC10976629 DOI: 10.1021/acs.chemmater.3c03257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 04/04/2024]
Abstract
Transparent conducting oxides (TCOs) possess a unique combination of optical transparency and electrical conductivity, making them indispensable in optoelectronic applications. However, their heavy dependence on a small number of established materials limits the range of devices that they can support. The discovery and development of additional wide bandgap oxides that can be doped to exhibit metallic-like conductivity are therefore necessary. In this work, we use hybrid density functional theory to identify a binary Sb(V) system, Sb2O5, as a promising TCO with high conductivity and transparency when doped with fluorine. We conducted a full point defect analysis, finding F-doped Sb2O5 to exhibit degenerate n-type transparent conducting behavior. The inherently large electron affinity found in antimony oxides also widens their application in organic solar cells. Following our previous work on zinc antimonate, this work provides additional support for designing Sb(V)-based oxides as cost-effective TCOs for a broader range of applications.
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Affiliation(s)
- Ke Li
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
| | - Joe Willis
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
| | - Seán R. Kavanagh
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
- Department
of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
| | - David O. Scanlon
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
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3
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Liu Z, Haque MA, Savory CN, Liu T, Matsuishi S, Fenwick O, Scanlon DO, Zwijnenburg MA, Baran D, Schroeder BC. Controlling the thermoelectric properties of organo-metallic coordination polymers through backbone geometry. Faraday Discuss 2024; 250:377-389. [PMID: 37965928 PMCID: PMC10926974 DOI: 10.1039/d3fd00139c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/06/2023] [Indexed: 11/16/2023]
Abstract
Poly(nickel-benzene-1,2,4,5-tetrakis(thiolate)) (Ni-btt), an organometallic coordination polymer (OMCP) characterized by the coordination between benzene-1,2,4,5-tetrakis(thiolate) (btt) and Ni2+ ions, has been recognized as a promising p-type thermoelectric material. In this study, we employed a constitutional isomer based on benzene-1,2,3,4-tetrakis(thiolate) (ibtt) to generate the corresponding isomeric polymer, poly(nickel-benzene-1,2,3,4-tetrakis(thiolate)) (Ni-ibtt). Comparative analysis of Ni-ibtt and Ni-btt reveals several common infrared (IR) and Raman features attributed to their similar square-planar nickel-sulfur (Ni-S) coordination. Nevertheless, these two polymer isomers exhibit substantially different backbone geometries. Ni-btt possesses a linear backbone, whereas Ni-ibtt exhibits a more undulating, zig-zag-like structure. Consequently, Ni-ibtt demonstrates slightly higher solubility and an increased bandgap in comparison to Ni-btt. The most noteworthy dissimilarity, however, manifests in their thermoelectric properties. While Ni-btt exhibits p-type behavior, Ni-ibtt demonstrates n-type carrier characteristics. This intriguing divergence prompted further investigation into the influence of OMCP backbone geometry on the electronic structure and, particularly, the thermoelectric properties of these materials.
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Affiliation(s)
- Zilu Liu
- Department of Chemistry, University College London, London WC1H 0AJ, UK.
| | - Md Azimul Haque
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division (PSE), KAUST Solar Center (KSC), 23955, Thuwal, Saudi Arabia.
| | - Chris N Savory
- Department of Chemistry, University College London, London WC1H 0AJ, UK.
- Thomas Young Centre, University College London, London WC1E 6BT, UK
| | - Tianjun Liu
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - Satoru Matsuishi
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Oliver Fenwick
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - David O Scanlon
- Department of Chemistry, University College London, London WC1H 0AJ, UK.
- Thomas Young Centre, University College London, London WC1E 6BT, UK
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Martijn A Zwijnenburg
- Department of Chemistry, University College London, London WC1H 0AJ, UK.
- Thomas Young Centre, University College London, London WC1E 6BT, UK
| | - Derya Baran
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division (PSE), KAUST Solar Center (KSC), 23955, Thuwal, Saudi Arabia.
| | - Bob C Schroeder
- Department of Chemistry, University College London, London WC1H 0AJ, UK.
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4
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Elgaml M, Dey S, Cen J, Avdeev M, Scanlon DO, Grey CP, Clarke SJ. Controlling the Superconductivity of Nb 2Pd xS 5 via Reversible Li Intercalation. Inorg Chem 2024; 63:1151-1165. [PMID: 38174709 DOI: 10.1021/acs.inorgchem.3c03524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The Nb2PdxS5 (x ≈ 0.74) superconductor with a Tc of 6.5 K is reduced by the intercalation of lithium in ammonia solution or electrochemically to produce an intercalated phase with expanded lattice parameters. The structure expands by 2% in volume and maintains the C2/m symmetry and rigidity due to the PdS4 units linking the layers. Experimental and computational analysis of the chemically synthesized bulk sample shows that Li occupies triangular prismatic sites between the layers with an occupancy of 0.33(4). This level of intercalation suppresses the superconductivity, with the injection of electrons into the metallic system observed to also reduce the Pauli paramagnetism by ∼40% as the bands are filled to a Fermi level with a lower density of states than in the host material. Deintercalation using iodine partially restores the superconductivity, albeit at a lower Tc of ∼5.5 K and with a smaller volume fraction than in fresh Nb2PdxS5. Electrochemical intercalation reproduces the chemical intercalation product at low Li content (<0.4) and also enables greater reduction, but at higher Li contents (≥0.4) accessed by this route, phase separation occurs with the indication that Li occupies another site.
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Affiliation(s)
- Mahmoud Elgaml
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, U.K
| | - Sunita Dey
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Jiayi Cen
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Maxim Avdeev
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
- School of Chemistry, The University of Sydney, Sydney 2006, Australia
| | - David O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Clare P Grey
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Simon J Clarke
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, U.K
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5
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Bhatia H, Guo J, Savory CN, Rush M, James DI, Dey A, Chen C, Bučar DK, Clarke TM, Scanlon DO, Palgrave RG, Schroeder BC. Exploring Bismuth Coordination Complexes as Visible-Light Absorbers: Synthesis, Characterization, and Photophysical Properties. Inorg Chem 2024; 63:416-430. [PMID: 38101319 PMCID: PMC10777407 DOI: 10.1021/acs.inorgchem.3c03290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/02/2023] [Accepted: 11/24/2023] [Indexed: 12/17/2023]
Abstract
Bismuth-based coordination complexes are advantageous over other metal complexes, as bismuth is the heaviest nontoxic element with high spin-orbit coupling and potential optoelectronics applications. Herein, four bismuth halide-based coordination complexes [Bi2Cl6(phen-thio)2] (1), [Bi2Br6(phen-thio)2] (2), [Bi2I6(phen-thio)2] (3), and [Bi2I6(phen-Me)2] (4) were synthesized, characterized, and subjected to detailed photophysical studies. The complexes were characterized by single-crystal X-ray diffraction, powder X-ray diffraction, and NMR studies. Spectroscopic analyses of 1-4 in solutions of different polarities were performed to understand the role of the organic and inorganic components in determining the ground- and excited-state properties of the complexes. The photophysical properties of the complexes were characterized by ground-state absorption, steady-state photoluminescence, microsecond time-resolved photoluminescence, and absorption spectroscopy. Periodic density functional theory (DFT) calculations were performed on the solid-state structures to understand the role of the organic and inorganic parts of the complexes. The studies showed that changing the ancillary ligand from chlorine (Cl) and bromine (Br) to iodine (I) bathochromically shifts the absorption band along with enhancing the absorption coefficient. Also, changing the halides (Cl, Br to I) affects the photoluminescent quantum yields of the ligand-centered (LC) emissive state without markedly affecting the lifetimes. The combined results confirmed that ground-state properties are strongly influenced by the inorganic part, and the lower-energy excited state is LC. This study paves the way to design novel bismuth coordination complexes for optoelectronic applications by rigorously choosing the ligands and bismuth salt.
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Affiliation(s)
- Harsh Bhatia
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Junjun Guo
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Christopher N. Savory
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Thomas
Young Centre, University College London, London WC1E 6BT, United Kingdom
| | - Martyn Rush
- Polysolar
Ltd, High Cross, Aurora Cambridge at BAS, Madingley Rd, Cambridge CB3 0ET, United
Kingdom
| | - David Ian James
- Johnson
Matthey Technology Centre, Blount’s Court, Sonning Common, Reading RG4 9NH, United Kingdom
| | - Avishek Dey
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Charles Chen
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Dejan-Krešimir Bučar
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Tracey M. Clarke
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - David O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Thomas
Young Centre, University College London, London WC1E 6BT, United Kingdom
- Diamond
Light Source Ltd., Diamond House, Harwell
Science and Innovation Campus, Didcot, Oxfordshire OX11
0DE, United Kingdom
| | - Robert G. Palgrave
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Bob C. Schroeder
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
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6
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Willis J, Claes R, Zhou Q, Giantomassi M, Rignanese GM, Hautier G, Scanlon DO. Limits to Hole Mobility and Doping in Copper Iodide. Chem Mater 2023; 35:8995-9006. [PMID: 38027540 PMCID: PMC10653089 DOI: 10.1021/acs.chemmater.3c01628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 12/01/2023]
Abstract
Over one hundred years have passed since the discovery of the p-type transparent conducting material copper iodide, predating the concept of the "electron-hole" itself. Supercentenarian status notwithstanding, little is understood about the charge transport mechanisms in CuI. Herein, a variety of modeling techniques are used to investigate the charge transport properties of CuI, and limitations to the hole mobility over experimentally achievable carrier concentrations are discussed. Poor dielectric response is responsible for extensive scattering from ionized impurities at degenerately doped carrier concentrations, while phonon scattering is found to dominate at lower carrier concentrations. A phonon-limited hole mobility of 162 cm2 V-1 s-1 is predicted at room temperature. The simulated charge transport properties for CuI are compared to existing experimental data, and the implications for future device performance are discussed. In addition to charge transport calculations, the defect chemistry of CuI is investigated with hybrid functionals, revealing that reasonably localized holes from the copper vacancy are the predominant source of charge carriers. The chalcogens S and Se are investigated as extrinsic dopants, where it is found that despite relatively low defect formation energies, they are unlikely to act as efficient electron acceptors due to the strong localization of holes and subsequent deep transition levels.
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Affiliation(s)
- Joe Willis
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
| | - Romain Claes
- UCLouvain,
Institute of Condensed Matter and Nanosciences (IMCN), Chemin des Étoiles 8, Louvain-la-Neuve B-1348, Belgium
| | - Qi Zhou
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
| | - Matteo Giantomassi
- UCLouvain,
Institute of Condensed Matter and Nanosciences (IMCN), Chemin des Étoiles 8, Louvain-la-Neuve B-1348, Belgium
| | - Gian-Marco Rignanese
- UCLouvain,
Institute of Condensed Matter and Nanosciences (IMCN), Chemin des Étoiles 8, Louvain-la-Neuve B-1348, Belgium
| | - Geoffroy Hautier
- UCLouvain,
Institute of Condensed Matter and Nanosciences (IMCN), Chemin des Étoiles 8, Louvain-la-Neuve B-1348, Belgium
- Thayer
School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - David O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.
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7
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Grosso BF, Davies DW, Zhu B, Walsh A, Scanlon DO. Accessible chemical space for metal nitride perovskites. Chem Sci 2023; 14:9175-9185. [PMID: 37655035 PMCID: PMC10466337 DOI: 10.1039/d3sc02171h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/25/2023] [Indexed: 09/02/2023] Open
Abstract
Building on the extensive exploration of metal oxide and metal halide perovskites, metal nitride perovskites represent a largely unexplored class of materials. We report a multi-tier computational screening of this chemical space. From a pool of 3660 ABN3 compositions covering I-VIII, II-VII, III-VI and IV-V oxidation state combinations, 279 are predicted to be chemically feasible. The ground-state structures of the 25 most promising candidate compositions were explored through enumeration over octahedral tilt systems and global optimisation. We predict 12 dynamically and thermodynamically stable nitride perovskite materials, including YMoN3, YWN3, ZrTaN3, and LaMoN3. These feature significant electric polarisation and low predicted switching electric field, showing similarities with metal oxide perovskites and making them attractive for ferroelectric memory devices.
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Affiliation(s)
| | - Daniel W Davies
- Department of Chemistry, University College London London UK
| | - Bonan Zhu
- Department of Chemistry, University College London London UK
| | - Aron Walsh
- Department of Materials, Imperial College London London UK
| | - David O Scanlon
- Department of Chemistry, University College London London UK
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8
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Lee R, Quesada-Cabrera R, Willis J, Iqbal A, Parkin IP, Scanlon DO, Palgrave RG. Phase Quantification of Heterogeneous Surfaces Using DFT-Simulated Valence Band Photoemission Spectra. ACS Appl Mater Interfaces 2023; 15:39956-39965. [PMID: 37552034 PMCID: PMC10450682 DOI: 10.1021/acsami.3c06638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/24/2023] [Indexed: 08/09/2023]
Abstract
Quantifying the crystallographic phases present at a surface is an important challenge in fields such as functional materials and surface science. X-ray photoelectron spectroscopy (XPS) is routinely employed in surface characterization to identify and quantify chemical species through core line analysis. Valence band (VB) spectra contain characteristic but complex features that provide information on the electronic density of states (DoS) and thus can be understood theoretically using density functional theory (DFT). Here, we present a method of fitting experimental photoemission spectra with DFT models for quantitative analysis of heterogeneous systems, specifically mapping the anatase to rutile ratio across the surface of mixed-phase TiO2 thin films. The results were correlated with mapped photocatalytic activity measured using a resazurin-based smart ink. This method allows large-scale functional and surface composition mapping in heterogeneous systems and demonstrates the unique insights gained from DFT-simulated spectra on the electronic structure origins of complex VB spectral features.
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Affiliation(s)
- Roxy Lee
- Department
of Chemistry, UCL (University College London), 20 Gordon Street, London WC1H 0AJ, U.K.
| | - Raul Quesada-Cabrera
- Department
of Chemistry, UCL (University College London), 20 Gordon Street, London WC1H 0AJ, U.K.
- Department
of Chemistry, Institute of Environmental Studies and Natural Resources
(i-UNAT, FEAM), Universidad de Las Palmas
de Gran Canaria (ULPGC), Campus de Tafira, Las Palmas 35017, Spain
| | - Joe Willis
- Department
of Chemistry, UCL (University College London), 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, UCL (University College London), Gower Street, London WC1E 6BT, U.K.
- Diamond
Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K.
| | - Asif Iqbal
- Materials
Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 0C5, Canada
| | - Ivan P. Parkin
- Department
of Chemistry, UCL (University College London), 20 Gordon Street, London WC1H 0AJ, U.K.
| | - David O. Scanlon
- Department
of Chemistry, UCL (University College London), 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, UCL (University College London), Gower Street, London WC1E 6BT, U.K.
| | - Robert G. Palgrave
- Department
of Chemistry, UCL (University College London), 20 Gordon Street, London WC1H 0AJ, U.K.
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9
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Brlec K, Savory CN, Scanlon DO. Understanding the electronic structure of Y 2Ti 2O 5S 2 for green hydrogen production: a hybrid-DFT and GW study. J Mater Chem A Mater 2023; 11:16776-16787. [PMID: 38014403 PMCID: PMC10408711 DOI: 10.1039/d3ta02801a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 07/20/2023] [Indexed: 11/29/2023]
Abstract
Utilising photocatalytic water splitting to produce green hydrogen is the key to reducing the carbon footprint of this crucial chemical feedstock. In this study, density functional theory (DFT) is employed to gain insights into the photocatalytic performance of an up-and-coming photocatalyst Y2Ti2O5S2 from first principles. Eleven non-polar clean surfaces are evaluated at the generalised gradient approximation level to obtain a plate-like Wulff shape that agrees well with the experimental data. The (001), (101) and (211) surfaces are considered further at hybrid-DFT level to determine their band alignments with respect to vacuum. The large band offset between the basal (001) and side (101) and (211) surfaces confirms experimentally observed spatial separation of hydrogen and oxygen evolution facets. Furthermore, relevant optoelectronic bulk properties were established using a combination of hybrid-DFT and many-body perturbation theory. The optical absorption of Y2Ti2O5S2 weakly onsets due to dipole-forbidden transitions, and hybrid Wannier-Mott/Frenkel excitonic behaviour is predicted to occur due to the two-dimensional electronic structure, with an exciton binding energy of 0.4 eV.
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Affiliation(s)
- Katarina Brlec
- Department of Chemistry and Thomas Young Centre, University College London London UK
| | - Christopher N Savory
- Department of Chemistry and Thomas Young Centre, University College London London UK
| | - David O Scanlon
- Department of Chemistry and Thomas Young Centre, University College London London UK
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10
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Hyde PA, Cen J, Cassidy SJ, Rees NH, Holdship P, Smith RI, Zhu B, Scanlon DO, Clarke SJ. Lithium Intercalation into the Excitonic Insulator Candidate Ta 2NiSe 5. Inorg Chem 2023. [PMID: 37466301 PMCID: PMC10394660 DOI: 10.1021/acs.inorgchem.3c01510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
A new reduced phase derived from the excitonic insulator candidate Ta2NiSe5 has been synthesized via the intercalation of lithium. LiTa2NiSe5 crystallizes in the orthorhombic space group Pmnb (no. 62) with lattice parameters a = 3.50247(3) Å, b = 13.4053(4) Å, c = 15.7396(2) Å, and Z = 4, with an increase of the unit cell volume by 5.44(1)% compared with Ta2NiSe5. Significant rearrangement of the Ta-Ni-Se layers is observed, in particular a very significant relative displacement of the layers compared to the parent phase, similar to that which occurs under hydrostatic pressure. Neutron powder diffraction experiments and computational analysis confirm that Li occupies a distorted triangular prismatic site formed by Se atoms of adjacent Ta2NiSe5 layers with an average Li-Se bond length of 2.724(2) Å. Li-NMR experiments show a single Li environment at ambient temperature. Intercalation suppresses the distortion to monoclinic symmetry that occurs in Ta2NiSe5 at 328 K and that is believed to be driven by the formation of an excitonic insulating state. Magnetometry data show that the reduced phase has a smaller net diamagnetic susceptibility than Ta2NiSe5 due to the enhancement of the temperature-independent Pauli paramagnetism caused by the increased density of states at the Fermi level evident also from the calculations, consistent with the injection of electrons during intercalation and formation of a metallic phase.
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Affiliation(s)
- P A Hyde
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - J Cen
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, U.K
| | - S J Cassidy
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - N H Rees
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - P Holdship
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, U.K
| | - R I Smith
- Rutherford Appleton Laboratory, ISIS Facility, Harwell Campus, Didcot, Oxon OX11 0QX, U.K
| | - B Zhu
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, U.K
| | - D O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, U.K
| | - S J Clarke
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
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11
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Li D, Wang H, Li K, Zhu B, Jiang K, Backes D, Veiga LSI, Shi J, Roy P, Xiao M, Chen A, Jia Q, Lee TL, Dhesi SS, Scanlon DO, MacManus-Driscoll JL, van Aken PA, Zhang KHL, Li W. Emergent and robust ferromagnetic-insulating state in highly strained ferroelastic LaCoO 3 thin films. Nat Commun 2023; 14:3638. [PMID: 37336926 DOI: 10.1038/s41467-023-39369-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 06/09/2023] [Indexed: 06/21/2023] Open
Abstract
Transition metal oxides are promising candidates for the next generation of spintronic devices due to their fascinating properties that can be effectively engineered by strain, defects, and microstructure. An excellent example can be found in ferroelastic LaCoO3 with paramagnetism in bulk. In contrast, unexpected ferromagnetism is observed in tensile-strained LaCoO3 films, however, its origin remains controversial. Here we simultaneously reveal the formation of ordered oxygen vacancies and previously unreported long-range suppression of CoO6 octahedral rotations throughout LaCoO3 films. Supported by density functional theory calculations, we find that the strong modification of Co 3d-O 2p hybridization associated with the increase of both Co-O-Co bond angle and Co-O bond length weakens the crystal-field splitting and facilitates an ordered high-spin state of Co ions, inducing an emergent ferromagnetic-insulating state. Our work provides unique insights into underlying mechanisms driving the ferromagnetic-insulating state in tensile-strained ferroelastic LaCoO3 films while suggesting potential applications toward low-power spintronic devices.
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Affiliation(s)
- Dong Li
- College of Physics, MIIT Key Laboratory of Aerospace Information Materials and Physics, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, 211106, Nanjing, China
| | - Hongguang Wang
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
| | - Kaifeng Li
- College of Physics, MIIT Key Laboratory of Aerospace Information Materials and Physics, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, 211106, Nanjing, China
| | - Bonan Zhu
- Department of Chemistry, University College London, London, WC1H 0AJ, UK.
| | - Kai Jiang
- Department of Materials, East China Normal University, 200241, Shanghai, China.
- School of Arts and Sciences, Shanghai Dianji University, 200240, Shanghai, China.
| | - Dirk Backes
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Larissa S I Veiga
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Jueli Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen, China
| | - Pinku Roy
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
- Department of Materials Design and Innovation, University at Buffalo-The State University of New York, Buffalo, NY, 14260, USA
| | - Ming Xiao
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK
| | - Aiping Chen
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - Quanxi Jia
- Department of Materials Design and Innovation, University at Buffalo-The State University of New York, Buffalo, NY, 14260, USA
| | - Tien-Lin Lee
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Sarnjeet S Dhesi
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - David O Scanlon
- Department of Chemistry, University College London, London, WC1H 0AJ, UK
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | | | - Peter A van Aken
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Kelvin H L Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen, China.
| | - Weiwei Li
- College of Physics, MIIT Key Laboratory of Aerospace Information Materials and Physics, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, 211106, Nanjing, China.
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12
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Nicolson A, Breternitz J, Kavanagh SR, Tomm Y, Morita K, Squires AG, Tovar M, Walsh A, Schorr S, Scanlon DO. Interplay of Static and Dynamic Disorder in the Mixed-Metal Chalcohalide Sn 2SbS 2I 3. J Am Chem Soc 2023. [PMID: 37253175 DOI: 10.1021/jacs.2c13336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Chalcohalide mixed-anion crystals have seen a rise in interest as "perovskite-inspired materials" with the goal of combining the ambient stability of metal chalcogenides with the exceptional optoelectronic performance of metal halides. Sn2SbS2I3 is a promising candidate, having achieved a photovoltaic power conversion efficiency above 4%. However, there is uncertainty over the crystal structure and physical properties of this crystal family. Using a first-principles cluster expansion approach, we predict a disordered room-temperature structure, comprising both static and dynamic cation disorder on different crystallographic sites. These predictions are confirmed using single-crystal X-ray diffraction. Disorder leads to a lowering of the bandgap from 1.8 eV at low temperature to 1.5 eV at the experimental annealing temperature of 573 K. Cation disorder tailoring the bandgap allows for targeted application or for the use in a graded solar cell, which when combined with material properties associated with defect and disorder tolerance, encourages further investigation into the group IV/V chalcohalide family for optoelectronic applications.
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Affiliation(s)
- Adair Nicolson
- Thomas Young Centre and Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Joachim Breternitz
- Helmholtz-Zentrum Berlin für Materialien und Energie, Structure and Dynamics of Energy Materials, Hahn-Meitner Platz 1, 14109 Berlin, Germany
| | - Seán R Kavanagh
- Thomas Young Centre and Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
- Thomas Young Centre and Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
| | - Yvonne Tomm
- Helmholtz-Zentrum Berlin für Materialien und Energie, Structure and Dynamics of Energy Materials, Hahn-Meitner Platz 1, 14109 Berlin, Germany
| | - Kazuki Morita
- Thomas Young Centre and Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
- Department of Chemistry, University of Pennsylvania, 231 S. 34 Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Alexander G Squires
- Thomas Young Centre and Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Michael Tovar
- Helmholtz-Zentrum Berlin für Materialien und Energie, Structure and Dynamics of Energy Materials, Hahn-Meitner Platz 1, 14109 Berlin, Germany
| | - Aron Walsh
- Thomas Young Centre and Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K
| | - Susan Schorr
- Helmholtz-Zentrum Berlin für Materialien und Energie, Structure and Dynamics of Energy Materials, Hahn-Meitner Platz 1, 14109 Berlin, Germany
- Department of Geosciences, Freie Universität Berlin, Malteserstraße 74-100, 12249 Berlin, Germany
| | - David O Scanlon
- Thomas Young Centre and Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
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13
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Choi YS, Costa SIR, Tapia-Ruiz N, Scanlon DO. Intrinsic Defects and Their Role in the Phase Transition of Na-Ion Anode Na 2Ti 3O 7. ACS Appl Energy Mater 2023; 6:484-495. [PMID: 36644111 PMCID: PMC9832431 DOI: 10.1021/acsaem.2c03466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
The development of high-power anode materials for Na-ion batteries is one of the primary obstacles due to the growing demands for their use in the smart grid. Despite the appealingly low cost and non-toxicity, Na2Ti3O7 suffers from low electrical conductivity and poor structural stability, which restricts its use in high-power applications. Viable approaches for overcoming these drawbacks reported to date are aliovalent doping and hydrogenation/hydrothermal treatments, both of which are closely intertwined with native defects. There is still a lack of knowledge, however, of the intrinsic defect chemistry of Na2Ti3O7, which impairs the rational design of high-power titanate anodes. Here, we report hybrid density functional theory calculations of the native defect chemistry of Na2Ti3O7. The defect calculations show that the insulating properties of Na2Ti3O7 arise from the Na and O Schottky disorder that act as major charge compensators. Under high-temperature hydrogenation treatment, these Schottky pairs of Na and O vacancies become dominant defects in Na2Ti3O7, triggering the spontaneous partial phase transition to Na2Ti6O13 and improving the electrical conductivity of the composite anode. Our findings provide an explanation on the interplay between intrinsic defects, structural phase transitions, and electrical conductivity, which can aid understanding of the properties of composite materials obtained from phase transitions.
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Affiliation(s)
- Yong-Seok Choi
- Department
of Materials Science and Engineering, Dankook
University, Cheonan31116, South Korea
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Sara I. R. Costa
- The
Faraday Institution, Harwell Campus, DidcotOX11 0RA, U.K.
- Department
of Chemistry, Lancaster University, LancasterLA1 4YB, U.K.
| | - Nuria Tapia-Ruiz
- The
Faraday Institution, Harwell Campus, DidcotOX11 0RA, U.K.
- Department
of Chemistry, Lancaster University, LancasterLA1 4YB, U.K.
| | - David O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
- The
Faraday Institution, Harwell Campus, DidcotOX11 0RA, U.K.
- Thomas
Young Centre, University College London, Gower Street, LondonWC1E 6BT, U.K.
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14
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Jones LH, Xing Z, Swallow JEN, Shiel H, Featherstone TJ, Smiles MJ, Fleck N, Thakur PK, Lee TL, Hardwick LJ, Scanlon DO, Regoutz A, Veal TD, Dhanak VR. Band Alignments, Electronic Structure, and Core-Level Spectra of Bulk Molybdenum Dichalcogenides (MoS 2, MoSe 2, and MoTe 2). J Phys Chem C Nanomater Interfaces 2022; 126:21022-21033. [PMID: 36561200 PMCID: PMC9761681 DOI: 10.1021/acs.jpcc.2c05100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/12/2022] [Indexed: 06/17/2023]
Abstract
A comprehensive study of bulk molybdenum dichalcogenides is presented with the use of soft and hard X-ray photoelectron (SXPS and HAXPES) spectroscopy combined with hybrid density functional theory (DFT). The main core levels of MoS2, MoSe2, and MoTe2 are explored. Laboratory-based X-ray photoelectron spectroscopy (XPS) is used to determine the ionization potential (IP) values of the MoX2 series as 5.86, 5.40, and 5.00 eV for MoSe2, MoSe2, and MoTe2, respectively, enabling the band alignment of the series to be established. Finally, the valence band measurements are compared with the calculated density of states which shows the role of p-d hybridization in these materials. Down the group, an increase in the p-d hybridization from the sulfide to the telluride is observed, explained by the configuration energy of the chalcogen p orbitals becoming closer to that of the valence Mo 4d orbitals. This pushes the valence band maximum closer to the vacuum level, explaining the decreasing IP down the series. High-resolution SXPS and HAXPES core-level spectra address the shortcomings of the XPS analysis in the literature. Furthermore, the experimentally determined band alignment can be used to inform future device work.
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Affiliation(s)
- Leanne
A. H. Jones
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Zongda Xing
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Jack E. N. Swallow
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Huw Shiel
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Thomas J. Featherstone
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Matthew J. Smiles
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Nicole Fleck
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Pardeep K. Thakur
- Diamond
Light Source Ltd., Diamond House, Harwell
Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
| | - Tien-Lin Lee
- Diamond
Light Source Ltd., Diamond House, Harwell
Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
| | - Laurence J. Hardwick
- Stephenson
Institute for Renewable Energy and Department of Chemistry, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - David O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Anna Regoutz
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Tim D. Veal
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Vinod R. Dhanak
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
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15
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Kavanagh SR, Savory CN, Liga SM, Konstantatos G, Walsh A, Scanlon DO. Frenkel Excitons in Vacancy-Ordered Titanium Halide Perovskites (Cs 2TiX 6). J Phys Chem Lett 2022; 13:10965-10975. [PMID: 36414263 PMCID: PMC9720747 DOI: 10.1021/acs.jpclett.2c02436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/15/2022] [Indexed: 05/28/2023]
Abstract
Low-cost, nontoxic, and earth-abundant photovoltaic materials are long-sought targets in the solar cell research community. Perovskite-inspired materials have emerged as promising candidates for this goal, with researchers employing materials design strategies including structural, dimensional, and compositional transformations to avoid the use of rare and toxic elemental constituents, while attempting to maintain high optoelectronic performance. These strategies have recently been invoked to propose Ti-based vacancy-ordered halide perovskites (A2TiX6; A = CH3NH3, Cs, Rb, or K; X = I, Br, or Cl) for photovoltaic operation, following the initial promise of Cs2SnX6 compounds. Theoretical investigations of these materials, however, consistently overestimate their band gaps, a fundamental property for photovoltaic applications. Here, we reveal strong excitonic effects as the origin of this discrepancy between theory and experiment, a consequence of both low structural dimensionality and band localization. These findings have vital implications for the optoelectronic application of these compounds while also highlighting the importance of frontier-orbital character for chemical substitution in materials design strategies.
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Affiliation(s)
- Seán R. Kavanagh
- Thomas
Young Centre and Department of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
- Thomas
Young Centre and Department of Materials, Imperial College London, Exhibition Road, LondonSW7 2AZ, U.K.
| | - Christopher N. Savory
- Thomas
Young Centre and Department of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Shanti M. Liga
- ICFO,
Institut de Ciencies Fotoniques, The Barcelona
Institute of Science and Technology, Castelldefels, 08860Barcelona, Spain
| | - Gerasimos Konstantatos
- ICFO,
Institut de Ciencies Fotoniques, The Barcelona
Institute of Science and Technology, Castelldefels, 08860Barcelona, Spain
- ICREA, Institució Catalana de Recerca i Estudis Avançats, 08010Barcelona, Spain
| | - Aron Walsh
- Thomas
Young Centre and Department of Materials, Imperial College London, Exhibition Road, LondonSW7 2AZ, U.K.
| | - David O. Scanlon
- Thomas
Young Centre and Department of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
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16
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Jackson AJ, Parrett BJ, Willis J, Ganose AM, Leung WWW, Liu Y, Williamson BAD, Kim TK, Hoesch M, Veiga LSI, Kalra R, Neu J, Schmuttenmaer CA, Lee TL, Regoutz A, Lee TC, Veal TD, Palgrave RG, Perry R, Scanlon DO. Computational Prediction and Experimental Realization of Earth-Abundant Transparent Conducting Oxide Ga-Doped ZnSb 2O 6. ACS Energy Lett 2022; 7:3807-3816. [PMID: 36398093 PMCID: PMC9664443 DOI: 10.1021/acsenergylett.2c01961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
Transparent conducting oxides have become ubiquitous in modern optoelectronics. However, the number of oxides that are transparent to visible light and have the metallic-like conductivity necessary for applications is limited to a handful of systems that have been known for the past 40 years. In this work, we use hybrid density functional theory and defect chemistry analysis to demonstrate that tri-rutile zinc antimonate, ZnSb2O6, is an ideal transparent conducting oxide and to identify gallium as the optimal dopant to yield high conductivity and transparency. To validate our computational predictions, we have synthesized both powder samples and single crystals of Ga-doped ZnSb2O6 which conclusively show behavior consistent with a degenerate transparent conducting oxide. This study demonstrates the possibility of a family of Sb(V)-containing oxides for transparent conducting oxide and power electronics applications.
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Affiliation(s)
- Adam J. Jackson
- Scientific
Computing Department, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and
Innovation Campus, Didcot, OxfordshireOX11 0QX, U.K.
| | - Benjamin J. Parrett
- London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gordon Street, LondonWC1E 6BT, U.K.
- Diamond
Light Source Ltd., Harwell Science
and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
| | - Joe Willis
- Diamond
Light Source Ltd., Harwell Science
and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, LondonWC1E 6BT, U.K.
| | - Alex M. Ganose
- Department
of Materials, Imperial College London, Exhibition Road, LondonSW7 2AZ, U.K.
| | - W. W. Winnie Leung
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Yuhan Liu
- London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gordon Street, LondonWC1E 6BT, U.K.
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Benjamin A. D. Williamson
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), Trondheim7491, Norway
| | - Timur K. Kim
- Diamond
Light Source Ltd., Harwell Science
and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
| | - Moritz Hoesch
- London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gordon Street, LondonWC1E 6BT, U.K.
- Diamond
Light Source Ltd., Harwell Science
and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
| | - Larissa S. I. Veiga
- London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gordon Street, LondonWC1E 6BT, U.K.
- Diamond
Light Source Ltd., Harwell Science
and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
| | - Raman Kalra
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Jens Neu
- Department
of Chemistry, Yale University, New Haven, Connecticut06520-8107, United States
| | | | - Tien-Lin Lee
- Diamond
Light Source Ltd., Harwell Science
and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
| | - Anna Regoutz
- Diamond
Light Source Ltd., Harwell Science
and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Tung-Chun Lee
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
- Institute
of Materials Discovery, University College
London, Malet Place, LondonWC1E 7JE, U.K.
| | - Tim D. Veal
- Department
of Physics and Stephenson Institute for Renewable Energy, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Robert G. Palgrave
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Robin Perry
- London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gordon Street, LondonWC1E 6BT, U.K.
- ISIS Pulsed Neutron and Muon Source, Rutherford
Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0QX, U.K.
| | - David O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, LondonWC1E 6BT, U.K.
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17
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Andreasen JW, Arca E, Bowers JW, Bär M, Breternitz J, Dale PJ, Dimitrievska M, Fermin DJ, Ganose A, Hages CJ, Hobson T, Jaramillo R, Kavanagh SR, Kayastha P, Kondrotas R, Lee J, Major JD, Mandati S, Mitzi DB, Scanlon DO, Schorr S, Scragg JJS, Shin B, Siebentritt S, Smiles M, Sood M, Sopiha KV, Spalatu N, Sutton M, Unold T, Valdes M, Walsh A, Wang M, Wang X, Weiss TP, Woo YW, Woods-Robinson R, Tiwari D. Novel chalcogenides, pnictides and defect-tolerant semiconductors: general discussion. Faraday Discuss 2022; 239:287-316. [PMID: 36250438 DOI: 10.1039/d2fd90057b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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18
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Andreasen JW, Bowers JW, Breternitz J, Dale PJ, Dimitrievska M, Fermin DJ, Ganose A, Gurieva G, Hages CJ, Hawkins C, Hobson TDC, Jaramillo R, Kavanagh SR, Major JD, Mandati S, Mitzi DB, Naylor MC, Platzer Björkman C, Scanlon DO, Schorr S, Scragg JJS, Shin B, Siebentritt S, Sood M, Sopiha KV, Sutton M, Tiwari D, Unold T, Valdes M, Wang M, Weiss TP, Woods-Robinson R. Indium-free CIGS analogues: general discussion. Faraday Discuss 2022; 239:85-111. [PMID: 36222895 DOI: 10.1039/d2fd90055f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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19
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Brlec K, Spooner KB, Skelton JM, Scanlon DO. Y 2Ti 2O 5S 2 - a promising n-type oxysulphide for thermoelectric applications. J Mater Chem A Mater 2022; 10:16813-16824. [PMID: 36092377 PMCID: PMC9382646 DOI: 10.1039/d2ta04160j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Thermoelectric materials offer an unambiguous solution to the ever-increasing global demand for energy by harnessing the Seebeck effect to convert waste heat to electrical energy. Mixed-anion materials are ideal candidate thermoelectric materials due to their thermal stability and potential for "phonon-glass, electron-crystal" behaviour. In this study, we use density-functional theory (DFT) calculations to investigate Y2Ti2O5S2, a cation-deficient Ruddlesden-Popper system, as a potential thermoelectric. We use hybrid DFT to calculate the electronic structure and band alignment, which indicate a preference for n-type doping with highly anisotropic in-plane and the out-of-plane charge-carrier mobilities as a result of the anisotropy in the crystal structure. We compute phonon spectra and calculate the lattice thermal conductivity within the single-mode relaxation-time approximation using lifetimes obtained by considering three-phonon interactions. We also calculate the transport properties using the momentum relaxation-time approximation to solve the electronic Boltzmann transport equations. The predicted transport properties and lattice thermal conductivity suggest a maximum in-plane ZT of 1.18 at 1000 K with a carrier concentration of 2.37 × 1020 cm-3. Finally, we discuss further the origins of the low lattice thermal conductivity, in particular exploring the possibility of nanostructuring to lower the phonon mean free path, reduce the thermal conductivity, and further enhance the ZT. Given the experimentally-evidenced high thermal stability and the favourable band alignment found in this work, Y2Ti2O5S2 has the potential to be a promising high-temperature n-type thermoelectric.
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Affiliation(s)
- Katarina Brlec
- Department of Chemistry, University College London 20 Gordon Street London UK
- Thomas Young Centre, University College London Gower Street London UK
| | - Kieran B Spooner
- Department of Chemistry, University College London 20 Gordon Street London UK
- Thomas Young Centre, University College London Gower Street London UK
| | - Jonathan M Skelton
- Department of Chemistry, University of Manchester Oxford Road Manchester UK
| | - David O Scanlon
- Department of Chemistry, University College London 20 Gordon Street London UK
- Thomas Young Centre, University College London Gower Street London UK
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20
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Kim YH, An JH, Kim SY, Li X, Song EJ, Park JH, Chung KY, Choi YS, Scanlon DO, Ahn HJ, Lee JC. Enabling 100C Fast-Charging Bulk Bi Anodes for Na-Ion Batteries. Adv Mater 2022; 34:e2201446. [PMID: 35524951 DOI: 10.1002/adma.202201446] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/13/2022] [Indexed: 06/14/2023]
Abstract
It is challenging to develop alloying anodes with ultrafast charging and large energy storage using bulk anode materials because of the difficulty of carrier-ion diffusion and fragmentation of the active electrode material. Herein, a rational strategy is reported to design bulk Bi anodes for Na-ion batteries that feature ultrafast charging, long cyclability, and large energy storage without using expensive nanomaterials and surface modifications. It is found that bulk Bi particles gradually transform into a porous nanostructure during cycling in a glyme-based electrolyte, whereas the resultant structure stores Na ions by forming phases with high Na diffusivity. These features allow the anodes to exhibit unprecedented electrochemical properties; the developed Na-Bi half-cell delivers 379 mA h g-1 (97% of that measured at 1C) at 7.7 A g-1 (20C) during 3500 cycles. It also retained 94% and 93% of the capacity measured at 1C even at extremely fast-charging rates of 80C and 100C, respectively. The structural origins of the measured properties are verified by experiments and first-principles calculations. The findings of this study not only broaden understanding of the underlying mechanisms of fast-charging anodes, but also provide basic guidelines for searching battery anodes that simultaneously exhibit high capacities, fast kinetics, and long cycling stabilities.
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Affiliation(s)
- Young-Hoon Kim
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, South Korea
| | - Jae-Hyun An
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, South Korea
| | - Sung-Yeob Kim
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, South Korea
| | - Xiangmei Li
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, South Korea
| | - Eun-Ji Song
- Department of Materials Engineering and Convergence Technology, Gyeongsang National University, Jinju, 52828, South Korea
| | - Jae-Ho Park
- Energy Storage Research Center, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - Kyung Yoon Chung
- Energy Storage Research Center, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- Division of Energy and Environment Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, South Korea
| | - Yong-Seok Choi
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
- Thomas Young Centre, University College London, Gower Street, London, WC1E 6BT, UK
| | - David O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
- Thomas Young Centre, University College London, Gower Street, London, WC1E 6BT, UK
| | - Hyo-Jun Ahn
- Department of Materials Engineering and Convergence Technology, Gyeongsang National University, Jinju, 52828, South Korea
| | - Jae-Chul Lee
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, South Korea
- Institute of Green Manufacturing Technology, Korea University, Seoul, 02841, South Korea
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21
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Willis J, Bravić I, Schnepf RR, Heinselman KN, Monserrat B, Unold T, Zakutayev A, Scanlon DO, Crovetto A. Prediction and realisation of high mobility and degenerate p-type conductivity in CaCuP thin films. Chem Sci 2022; 13:5872-5883. [PMID: 35685803 PMCID: PMC9132065 DOI: 10.1039/d2sc01538b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/26/2022] [Indexed: 12/20/2022] Open
Abstract
Phosphides are interesting candidates for hole transport materials and p-type transparent conducting applications, capable of achieving greater valence band dispersion than their oxide counterparts due to the higher lying energy and increased size of the P 3p orbital. After computational identification of the indirect-gap semiconductor CaCuP as a promising candidate, we now report reactive sputter deposition of phase-pure p-type CaCuP thin films. Their intrinsic hole concentration and hole mobility exceed 1 × 1020 cm−3 and 35 cm2 V−1 s−1 at room temperature, respectively. Transport calculations indicate potential for even higher mobilities. Copper vacancies are identified as the main source of conductivity, displaying markedly different behaviour compared to typical p-type transparent conductors, leading to improved electronic properties. The optical transparency of CaCuP films is lower than expected from first principles calculations of phonon-mediated indirect transitions. This discrepancy could be partly attributed to crystalline imperfections within the films, increasing the strength of indirect transitions. We determine the transparent conductor figure of merit of CaCuP films as a function of composition, revealing links between stoichiometry, crystalline quality, and opto-electronic properties. These findings provide a promising initial assessment of the viability of CaCuP as a p-type transparent contact. We synthesize air-stable, p-type CaCuP thin films with high hole concentration and high hole mobility as potential p-type transparent conductors. We study their optoelectronic properties in detail by advanced experimental and computational methods.![]()
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Affiliation(s)
- Joe Willis
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK .,Thomas Young Centre, University College London Gower Street London WC1E 6BT UK.,Diamond Light Source Ltd, Harwell Science and Innovation Campus Didcot Oxfordshire OX11 0DE UK
| | - Ivona Bravić
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK
| | - Rekha R Schnepf
- National Renewable Energy Laboratory Golden Colorado 80401 USA .,Department of Physics, Colorado School of Mines Golden Colorado 80401 USA
| | | | - Bartomeu Monserrat
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK.,Department of Materials Science and Metallurgy, University of Cambridge 27 Charles Babbage Road Cambridge CB3 0FS UK
| | - Thomas Unold
- Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, GmbH Berlin Germany
| | | | - David O Scanlon
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK .,Thomas Young Centre, University College London Gower Street London WC1E 6BT UK
| | - Andrea Crovetto
- National Renewable Energy Laboratory Golden Colorado 80401 USA .,Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, GmbH Berlin Germany
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22
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Verma S, Rivera M, Scanlon DO, Walsh A. Machine learned calibrations to high-throughput molecular excited state calculations. J Chem Phys 2022; 156:134116. [PMID: 35395896 DOI: 10.1063/5.0084535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Understanding the excited state properties of molecules provides insight into how they interact with light. These interactions can be exploited to design compounds for photochemical applications, including enhanced spectral conversion of light to increase the efficiency of photovoltaic cells. While chemical discovery is time- and resource-intensive experimentally, computational chemistry can be used to screen large-scale databases for molecules of interest in a procedure known as high-throughput virtual screening. The first step usually involves a high-speed but low-accuracy method to screen large numbers of molecules (potentially millions), so only the best candidates are evaluated with expensive methods. However, use of a coarse first-pass screening method can potentially result in high false positive or false negative rates. Therefore, this study uses machine learning to calibrate a high-throughput technique [eXtended Tight Binding based simplified Tamm-Dancoff approximation (xTB-sTDA)] against a higher accuracy one (time-dependent density functional theory). Testing the calibration model shows an approximately sixfold decrease in the error in-domain and an approximately threefold decrease in the out-of-domain. The resulting mean absolute error of ∼0.14 eV is in line with previous work in machine learning calibrations and out-performs previous work in linear calibration of xTB-sTDA. We then apply the calibration model to screen a 250k molecule database and map inaccuracies of xTB-sTDA in chemical space. We also show generalizability of the workflow by calibrating against a higher-level technique (CC2), yielding a similarly low error. Overall, this work demonstrates that machine learning can be used to develop a cost-effective and accurate method for large-scale excited state screening, enabling accelerated molecular discovery across a variety of disciplines.
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Affiliation(s)
- Shomik Verma
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Miguel Rivera
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - David O Scanlon
- Department of Chemistry and Thomas Young Centre, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Aron Walsh
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
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23
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Limburn GJ, Davies DW, Langridge N, Malik Z, Williamson BAD, Scanlon DO, Hyett G. Investigation of factors affecting the stability of compounds formed by isovalent substitution in layered oxychalcogenides, leading to identification of Ba 3Sc 2O 5Cu 2Se 2, Ba 3Y 2O 5Cu 2S 2, Ba 3Sc 2O 5Ag 2Se 2 and Ba 3In 2O 5Ag 2Se 2. J Mater Chem C Mater 2022; 10:3784-3795. [PMID: 36325578 PMCID: PMC9558239 DOI: 10.1039/d1tc05051f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/07/2022] [Indexed: 06/16/2023]
Abstract
Four novel compositions containing chalcogenide layers, adopting the Ba3M2O5M'2Ch2 layered structure have been identified: Ba3Sc2O5Cu2Se2, Ba3Y2O5Cu2S2, Ba3Sc2O5Ag2Se2 and Ba3In2O5Ag2Se2. A comprehensive comparison of experimental and computational results providing the crystallographic and electronic structure of the compounds under investigation has been conducted. Materials were synthesised at 800 °C under vacuum using a conventional ceramic synthesis route with combination of binary oxide and chalcogenide precursors. We report their structures determined by Rietveld refinement of X-ray powder diffraction patterns, and band gaps determined from optical measurements, which range from 1.44 eV to 3.04 eV. Through computational modelling we can also present detailed band structures and propose that, based on their predicted transport properties, Ba3Sc2O5Ag2Se2 has potential as a visible light photocatalyst and Ba3Sc2O5Cu2Se2 is of interest as a p-type transparent conductor. These four novel compounds are part of a larger series of sixteen compounds adopting the Ba3M2O5M'2Ch2 structure that we have considered, of which approximately half are stable and can be synthesized. Analysis of the compounds that cannot be synthesized from this group allows us to identify why compounds containing either M = La, or silver sulfide chalcogenide layers, cannot be formed in this structure type.
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Affiliation(s)
- Gregory J Limburn
- School of Chemistry, University of Southampton Southampton SO17 1BJ UK
| | - Daniel W Davies
- Department of Chemistry, University College London, 20 Gordon Street London WC1H 0AJ UK
- Research Computing Service, Information and Communication Technology, Imperial College London London SW7 2AZ UK
| | - Neil Langridge
- School of Chemistry, University of Southampton Southampton SO17 1BJ UK
| | - Zahida Malik
- School of Chemistry, University of Southampton Southampton SO17 1BJ UK
| | - Benjamin A D Williamson
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway
| | - David O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street London WC1H 0AJ UK
| | - Geoffrey Hyett
- School of Chemistry, University of Southampton Southampton SO17 1BJ UK
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24
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Brlec K, Kavanagh SR, Savory CN, Scanlon DO. Understanding the Photocatalytic Activity of La 5Ti 2AgS 5O 7 and La 5Ti 2CuS 5O 7 for Green Hydrogen Production: Computational Insights. ACS Appl Energy Mater 2022; 5:1992-2001. [PMID: 35252776 PMCID: PMC8889536 DOI: 10.1021/acsaem.1c03534] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
Green production of hydrogen is possible with photocatalytic water splitting, where hydrogen is produced while water is reduced by using energy derived from light. In this study, density functional theory (DFT) is employed to gain insights into the photocatalytic performance of La5Ti2AgS5O7 and La5Ti2CuS5O7-two emerging candidate materials for water splitting. The electronic structure of both bulk materials was calculated by using hybrid DFT, which indicated the band gaps and charge carrier effective masses are suitable for photocatalytic water splitting. Notably, the unique one-dimensional octahedral TiO x S6-x and tetragonal MS4 channels formed provide a structural separation for photoexcited charge carriers which should inhibit charge recombination. Band alignments of surfaces that appear on the Wulff constructions of 12 nonpolar symmetric surface slabs were calculated by using hybrid DFT for each of the materials. All surfaces of La5Ti2AgS5O7 have band edge positions suitable for hydrogen evolution; however, the small overpotentials on the largest facets likely decrease the photocatalytic activity. In La5Ti2CuS5O7, 72% of the surface area can support oxygen evolution thermodynamically and kinetically. Based on their similar electronic structures, La5Ti2AgS5O7 and La5Ti2CuS5O7 could be effectively employed in Z-scheme photocatalytic water splitting.
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Affiliation(s)
- Katarina Brlec
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
| | - Seán R. Kavanagh
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
- Department
of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
| | - Christopher N. Savory
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
| | - David O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
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25
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Shi J, Rubinstein EA, Li W, Zhang J, Yang Y, Lee T, Qin C, Yan P, MacManus‐Driscoll JL, Scanlon DO, Zhang KH. Modulation of the Bi 3+ 6s 2 Lone Pair State in Perovskites for High-Mobility p-Type Oxide Semiconductors. Adv Sci (Weinh) 2022; 9:e2104141. [PMID: 34997681 PMCID: PMC8867164 DOI: 10.1002/advs.202104141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/12/2021] [Indexed: 06/14/2023]
Abstract
Oxide semiconductors are key materials in many technologies from flat-panel displays,solar cells to transparent electronics. However, many potential applications are hindered by the lack of high mobility p-type oxide semiconductors due to the localized O-2p derived valence band (VB) structure. In this work, the VB structure modulation is reported for perovskite Ba2 BiMO6 (M = Bi, Nb, Ta) via the Bi 6s2 lone pair state to achieve p-type oxide semiconductors with high hole mobility up to 21 cm2 V-1 s-1 , and optical bandgaps widely varying from 1.5 to 3.2 eV. Pulsed laser deposition is used to grow high quality epitaxial thin films. Synergistic combination of hard x-ray photoemission, x-ray absorption spectroscopies, and density functional theory calculations are used to gain insight into the electronic structure of Ba2 BiMO6 . The high mobility is attributed to the highly dispersive VB edges contributed from the strong coupling of Bi 6s with O 2p at the top of VB that lead to low hole effective masses (0.4-0.7 me ). Large variation in bandgaps results from the change in the energy positions of unoccupied Bi 6s orbital or Nb/Ta d orbitals that form the bottom of conduction band. P-N junction diode constructed with p-type Ba2 BiTaO6 and n-type Nb doped SrTiO3 exhibits high rectifying ratio of 1.3 × 104 at ±3 V, showing great potential in fabricating high-quality devices. This work provides deep insight into the electronic structure of Bi3+ based perovskites and guides the development of new p-type oxide semiconductors.
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Affiliation(s)
- Jueli Shi
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy MaterialsCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China
| | - Ethan A. Rubinstein
- Department of Chemistry and Thomas Young CentreUniversity College LondonLondonWC1H 0AJUK
| | - Weiwei Li
- MIIT Key Laboratory of Aerospace Information Materials and PhysicsCollege of ScienceNanjing University of Aeronautics and AstronauticsNanjing211106China
- Department of Materials Science and MetallurgyUniversity of Cambridge27 Charles Babbage RoadCambridgeCB3 0FSUK
| | - Jiaye Zhang
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy MaterialsCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China
| | - Ye Yang
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy MaterialsCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China
| | - Tien‐Lin Lee
- Diamond Light Source Ltd.Harwell Science and Innovation CampusDidcotOX11 0DEUK
| | - Changdong Qin
- Beijing Key Laboratory of Microstructure and Property of SolidsFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing100124China
| | - Pengfei Yan
- Beijing Key Laboratory of Microstructure and Property of SolidsFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing100124China
| | - Judith L. MacManus‐Driscoll
- Department of Materials Science and MetallurgyUniversity of Cambridge27 Charles Babbage RoadCambridgeCB3 0FSUK
| | - David O. Scanlon
- Department of Chemistry and Thomas Young CentreUniversity College LondonLondonWC1H 0AJUK
| | - Kelvin H.L. Zhang
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy MaterialsCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China
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26
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Agbenyeke R, Andreasen J, Benhaddou N, Bowers JW, Breternitz J, Bär M, Dimitrievska M, Fermin DJ, Ganose A, Hawkins C, Jaramillo R, Kavanagh SR, Kondrotas R, Major JD, Mandati S, Nicolson A, Platzer Björkman C, Savory C, Scanlon DO, Schorr S, Scragg JJS, Sheppard A, Shin B, Siebentritt S, Sood M, Sopiha KV, Spalatu N, Tang J, Walsh A, Weiss TP, Woods-Robinson R, Yetkin HA. Materials design and bonding: general discussion. Faraday Discuss 2022; 239:375-404. [DOI: 10.1039/d2fd90058k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Abstract
The efficiency of a solar cell is often limited by electron–hole recombination mediated by defect states within the band gap of the photovoltaic (PV) semiconductor. The Shockley–Read–Hall (SRH) model considers a static trap that can successively capture electrons and holes. In reality however, true trap levels vary with both the defect charge state and local structure. Here we consider the role of metastable structural configurations in capturing electrons and holes, taking the tellurium interstitial in CdTe as an illustrative example. Consideration of the defect dynamics, and symmetry-breaking, changes the qualitative behaviour and activates new pathways for carrier capture. Our results reveal the potential importance of metastable defect structures in non-radiative recombination, in particular for semiconductors with anharmonic/ionic–covalent bonding, multinary compositions, low crystal symmetries or highly-mobile defects. Metastable defect structures can activate novel pathways for electron–hole recombination in semiconductors – particularly for inorganic compounds with anharmonic/mixed bonding, multinary composition, low symmetry and/or highly-mobile defects.![]()
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Affiliation(s)
- Seán R Kavanagh
- Department of Chemistry & Thomas Young Centre, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
- Department of Materials & Thomas Young Centre, Imperial College London, Exhibition Road, London SW7 2AZ, UK
| | - David O Scanlon
- Department of Chemistry & Thomas Young Centre, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
| | - Aron Walsh
- Department of Chemistry & Thomas Young Centre, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Christoph Freysoldt
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany
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28
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Krajewska CJ, Kavanagh SR, Zhang L, Kubicki DJ, Dey K, Gałkowski K, Grey CP, Stranks SD, Walsh A, Scanlon DO, Palgrave RG. Enhanced visible light absorption in layered Cs 3Bi 2Br 9 through mixed-valence Sn(ii)/Sn(iv) doping. Chem Sci 2021; 12:14686-14699. [PMID: 34820084 PMCID: PMC8597838 DOI: 10.1039/d1sc03775g] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/04/2021] [Indexed: 11/21/2022] Open
Abstract
Lead-free halides with perovskite-related structures, such as the vacancy-ordered perovskite Cs3Bi2Br9, are of interest for photovoltaic and optoelectronic applications. We find that addition of SnBr2 to the solution-phase synthesis of Cs3Bi2Br9 leads to substitution of up to 7% of the Bi(iii) ions by equal quantities of Sn(ii) and Sn(iv). The nature of the substitutional defects was studied by X-ray diffraction, 133Cs and 119Sn solid state NMR, X-ray photoelectron spectroscopy and density functional theory calculations. The resulting mixed-valence compounds show intense visible and near infrared absorption due to intervalence charge transfer, as well as electronic transitions to and from localised Sn-based states within the band gap. Sn(ii) and Sn(iv) defects preferentially occupy neighbouring B-cation sites, forming a double-substitution complex. Unusually for a Sn(ii) compound, the material shows minimal changes in optical and structural properties after 12 months storage in air. Our calculations suggest the stabilisation of Sn(ii) within the double substitution complex contributes to this unusual stability. These results expand upon research on inorganic mixed-valent halides to a new, layered structure, and offer insights into the tuning, doping mechanisms, and structure-property relationships of lead-free vacancy-ordered perovskite structures.
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Affiliation(s)
- Chantalle J Krajewska
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Seán R Kavanagh
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK .,Thomas Young Centre, University College London Gower Street London WC1E 6BT UK.,Department of Materials, Imperial College London Exhibition Road London SW72AZ UK
| | - Lina Zhang
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Dominik J Kubicki
- Cavendish Laboratory, University of Cambridge JJ Thomson Avenue Cambridge CB3 0HE UK.,Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Krishanu Dey
- Cavendish Laboratory, University of Cambridge JJ Thomson Avenue Cambridge CB3 0HE UK
| | - Krzysztof Gałkowski
- Cavendish Laboratory, University of Cambridge JJ Thomson Avenue Cambridge CB3 0HE UK.,Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University 87-100 Toruń Poland.,Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology 50-370 Wroclaw Poland
| | - Clare P Grey
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Samuel D Stranks
- Cavendish Laboratory, University of Cambridge JJ Thomson Avenue Cambridge CB3 0HE UK.,Department of Chemical Engineering & Biotechnology, University of Cambridge Philippa Fawcett Drive Cambridge CB3 0AS UK
| | - Aron Walsh
- Department of Materials, Imperial College London Exhibition Road London SW72AZ UK.,Department of Materials Science and Engineering, Yonsei University Seoul 03722 Korea
| | - David O Scanlon
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK .,Thomas Young Centre, University College London Gower Street London WC1E 6BT UK.,Diamond Light Source Ltd. Diamond House, Harwell Science and Innovation Campus, Didcot Oxfordshire OX11 0DE UK
| | - Robert G Palgrave
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
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29
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Kavanagh SR, Savory CN, Scanlon DO, Walsh A. Hidden spontaneous polarisation in the chalcohalide photovoltaic absorber Sn 2SbS 2I 3. Mater Horiz 2021; 8:2709-2716. [PMID: 34617541 PMCID: PMC8489399 DOI: 10.1039/d1mh00764e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/01/2021] [Indexed: 05/10/2023]
Abstract
Perovskite-inspired materials aim to replicate the optoelectronic performance of lead-halide perovskites, while eliminating issues with stability and toxicity. Chalcohalides of group IV/V elements have attracted attention due to enhanced stability provided by stronger metal-chalcogen bonds, alongside compositional flexibility and ns2 lone pair cations - a performance-defining feature of halide perovskites. Following the experimental report of solution-grown tin-antimony sulfoiodide (Sn2SbS2I3) solar cells, with power conversion efficiencies above 4%, we assess the structural and electronic properties of this emerging photovoltaic material. We find that the reported centrosymmetric Cmcm crystal structure represents an average over multiple polar Cmc21 configurations. The instability is confirmed through a combination of lattice dynamics and molecular dynamics simulations. We predict a large spontaneous polarisation of 37 μC cm-2 that could be active for electron-hole separation in operating solar cells. We further assess the radiative efficiency limit of this material, calculating ηmax > 30% for film thicknesses t > 0.5 μm.
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Affiliation(s)
- Seán R Kavanagh
- Department of Chemistry & Thomas Young Centre, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
- Department of Materials & Thomas Young Centre, Imperial College London, Exhibition Road, London SW7 2AZ, UK
| | - Christopher N Savory
- Department of Chemistry & Thomas Young Centre, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
| | - David O Scanlon
- Department of Chemistry & Thomas Young Centre, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Aron Walsh
- Department of Chemistry & Thomas Young Centre, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
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30
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Rahim W, Skelton JM, Scanlon DO. Ca 4Sb 2O and Ca 4Bi 2O: two promising mixed-anion thermoelectrics. J Mater Chem A Mater 2021; 9:20417-20435. [PMID: 34671477 PMCID: PMC8454491 DOI: 10.1039/d1ta03649a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
The environmental burden of fossil fuels and the rising impact of global warming have created an urgent need for sustainable clean energy sources. This has led to widespread interest in thermoelectric (TE) materials to recover part of the ∼60% of global energy currently wasted as heat as usable electricity. Oxides are particularly attractive as they are thermally stable, chemically inert, and formed of earth-abundant elements, but despite intensive efforts there have been no reports of oxide TEs matching the performance of flagship chalcogenide materials such as PbTe, Bi2Te3 and SnSe. A number of ternary X4Y2Z mixed-anion systems, including oxides, have predicted band gaps in the useful range for several renewable-energy applications, including as TEs, and some also show the complex crystal structures indicative of low lattice thermal conductivity. In this study, we use ab initio calculations to investigate the TE performance of two structurally-similar mixed-anion oxypnictides, Ca4Sb2O and Ca4Bi2O. Electronic-structure and band-alignment calculations using hybrid density-functional theory (DFT), including spin-orbit coupling, suggest that both materials are likely to be p-type dopable with large charge-carrier mobilities. Lattice-dynamics calculations using third-order perturbation theory predict ultra-low lattice thermal conductivities of ∼0.8 and ∼0.5 W m-1 K-1 above 750 K. Nanostructuring to a crystal grain size of 20 nm is predicted to further reduce the room temperature thermal conductivity by around 40%. Finally, we use the electronic- and thermal-transport calculations to estimate the thermoelectric figure of merit ZT, and show that with p-type doping both oxides could potentially serve as promising earth-abundant oxide TEs for high-temperature applications.
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Affiliation(s)
- Warda Rahim
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
- Thomas Young Centre, University College London Gower Street London WC1E 6BT UK
| | - Jonathan M Skelton
- Department of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK
| | - David O Scanlon
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
- Thomas Young Centre, University College London Gower Street London WC1E 6BT UK
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus Didcot Oxfordshire OX11 0DE UK
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31
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Tappan BA, Zhu B, Cottingham P, Mecklenburg M, Scanlon DO, Brutchey RL. Crystal Structure of Colloidally Prepared Metastable Ag 2Se Nanocrystals. Nano Lett 2021; 21:5881-5887. [PMID: 34196567 DOI: 10.1021/acs.nanolett.1c02045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Structural polymorphism is known for many bulk materials; however, on the nanoscale metastable polymorphs tend to form more readily than in the bulk, and with more structural variety. One such metastable polymorph observed for colloidal Ag2Se nanocrystals has traditionally been referred to as the "tetragonal" phase. While there are reports on the chemistry and properties of this metastable polymorph, its crystal structure, and therefore electronic structure, has yet to be determined. We report that an anti-PbCl2-like structure type (space group P21/n) more accurately describes the powder X-ray diffraction and X-ray total scattering patterns of colloidal Ag2Se nanocrystals prepared by several different methods. Density functional theory (DFT) calculations indicate that this anti-PbCl2-like Ag2Se polymorph is a dynamically stable, narrow-band-gap semiconductor. The anti-PbCl2-like structure of Ag2Se is a low-lying metastable polymorph at 5-25 meV/atom above the ground state, depending on the exchange-correlation functional used.
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Affiliation(s)
- Bryce A Tappan
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Bonan Zhu
- Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
| | - Patrick Cottingham
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Matthew Mecklenburg
- Core Center of Excellence in Nano Imaging, University of Southern California, Los Angeles, California 90089, United States
| | - David O Scanlon
- Department of Chemistry, University College London, London WC1H 0AJ, United Kingdom
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K
| | - Richard L Brutchey
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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32
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Huang YT, Kavanagh SR, Scanlon DO, Walsh A, Hoye RLZ. Corrigendum: Perovskite-inspired materials for photovoltaics and beyond-from design to devices (2021 Nanotechnology32132004). Nanotechnology 2021; 32:379501. [PMID: 34077912 DOI: 10.1088/1361-6528/ac074b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 06/02/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Yi-Teng Huang
- Department of Physics, University of Cambridge, JJ Thomson Ave, Cambridge CB3 0HE, United Kingdom
| | - Seán R Kavanagh
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - David O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Aron Walsh
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
- Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Republic of Korea
| | - Robert L Z Hoye
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
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33
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Abstract
Cathodes are critical components of rechargeable batteries. Conventionally, the search for cathode materials relies on experimental trial-and-error and a traversing of existing computational/experimental databases. While these methods have led to the discovery of several commercially viable cathode materials, the chemical space explored so far is limited and many phases will have been overlooked, in particular, those that are metastable. We describe a computational framework for battery cathode exploration based on ab initio random structure searching (AIRSS), an approach that samples local minima on the potential energy surface to identify new crystal structures. We show that by delimiting the search space using a number of constraints, including chemically aware minimum interatomic separations, cell volumes, and space group symmetries, AIRSS can efficiently predict both thermodynamically stable and metastable cathode materials. Specifically, we investigate LiCoO2, LiFePO4, and LixCuyFz to demonstrate the efficiency of the method by rediscovering the known crystal structures of these cathode materials. The effect of parameters, such as minimum separations and symmetries, on the efficiency of the sampling is discussed in detail. The adaptation of the minimum interatomic distances on a species-pair basis, from low-energy optimized structures to efficiently capture the local coordination environment of atoms, is explored. A family of novel cathode materials based on the transition-metal oxalates is proposed. They demonstrate superb energy density, oxygen-redox stability, and lithium diffusion properties. This article serves both as an introduction to the computational framework and as a guide to battery cathode material discovery using AIRSS.
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Affiliation(s)
- Ziheng Lu
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Bonan Zhu
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Benjamin W B Shires
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - David O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Chris J Pickard
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
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34
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Kavanagh S, Walsh A, Scanlon DO. Rapid Recombination by Cadmium Vacancies in CdTe. ACS Energy Lett 2021; 6:1392-1398. [PMID: 33869771 PMCID: PMC8043136 DOI: 10.1021/acsenergylett.1c00380] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 03/12/2021] [Indexed: 05/11/2023]
Abstract
CdTe is currently the largest thin-film photovoltaic technology. Non-radiative electron-hole recombination reduces the solar conversion efficiency from an ideal value of 32% to a current champion performance of 22%. The cadmium vacancy (VCd) is a prominent acceptor species in p-type CdTe; however, debate continues regarding its structural and electronic behavior. Using ab initio defect techniques, we calculate a negative-U double-acceptor level for VCd, while reproducing the VCd 1- hole-polaron, reconciling theoretical predictions with experimental observations. We find the cadmium vacancy facilitates rapid charge-carrier recombination, reducing maximum power-conversion efficiency by over 5% for untreated CdTe-a consequence of tellurium dimerization, metastable structural arrangements, and anharmonic potential energy surfaces for carrier capture.
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Affiliation(s)
- Seán
R. Kavanagh
- Thomas
Young Centre and Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre and Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
| | - Aron Walsh
- Thomas
Young Centre and Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
- Department
of Materials Science and Engineering, Yonsei
University, Seoul 03722, Republic of Korea
| | - David O. Scanlon
- Thomas
Young Centre and Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Diamond
Light Source Ltd., Diamond
House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11
0DE, U.K.
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35
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Huang YT, Kavanagh SR, Scanlon DO, Walsh A, Hoye RLZ. Perovskite-inspired materials for photovoltaics and beyond-from design to devices. Nanotechnology 2021; 32:132004. [PMID: 33260167 DOI: 10.1088/1361-6528/abcf6d] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Lead-halide perovskites have demonstrated astonishing increases in power conversion efficiency in photovoltaics over the last decade. The most efficient perovskite devices now outperform industry-standard multi-crystalline silicon solar cells, despite the fact that perovskites are typically grown at low temperature using simple solution-based methods. However, the toxicity of lead and its ready solubility in water are concerns for widespread implementation. These challenges, alongside the many successes of the perovskites, have motivated significant efforts across multiple disciplines to find lead-free and stable alternatives which could mimic the ability of the perovskites to achieve high performance with low temperature, facile fabrication methods. This Review discusses the computational and experimental approaches that have been taken to discover lead-free perovskite-inspired materials, and the recent successes and challenges in synthesizing these compounds. The atomistic origins of the extraordinary performance exhibited by lead-halide perovskites in photovoltaic devices is discussed, alongside the key challenges in engineering such high-performance in alternative, next-generation materials. Beyond photovoltaics, this Review discusses the impact perovskite-inspired materials have had in spurring efforts to apply new materials in other optoelectronic applications, namely light-emitting diodes, photocatalysts, radiation detectors, thin film transistors and memristors. Finally, the prospects and key challenges faced by the field in advancing the development of perovskite-inspired materials towards realization in commercial devices is discussed.
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Affiliation(s)
- Yi-Teng Huang
- Department of Physics, University of Cambridge, JJ Thomson Ave, Cambridge CB3 0HE, United Kingdom
| | - Seán R Kavanagh
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - David O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Aron Walsh
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
- Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Republic of Korea
| | - Robert L Z Hoye
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
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36
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Costa SIR, Choi Y, Fielding AJ, Naylor AJ, Griffin JM, Sofer Z, Scanlon DO, Tapia‐Ruiz N. Surface Engineering Strategy Using Urea To Improve the Rate Performance of Na 2 Ti 3 O 7 in Na-Ion Batteries. Chemistry 2021; 27:3875-3886. [PMID: 32852862 PMCID: PMC7986851 DOI: 10.1002/chem.202003129] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/14/2020] [Indexed: 11/23/2022]
Abstract
Na2 Ti3 O7 (NTO) is considered a promising anode material for Na-ion batteries due to its layered structure with an open framework and low and safe average operating voltage of 0.3 V vs. Na+ /Na. However, its poor electronic conductivity needs to be addressed to make this material attractive for practical applications among other anode choices. Here, we report a safe, controllable and affordable method using urea that significantly improves the rate performance of NTO by producing surface defects such as oxygen vacancies and hydroxyl groups, and the secondary phase Na2 Ti6 O13 . The enhanced electrochemical performance agrees with the higher Na+ ion diffusion coefficient, higher charge carrier density and reduced bandgap observed in these samples, without the need of nanosizing and/or complex synthetic strategies. A comprehensive study using a combination of diffraction, microscopic, spectroscopic and electrochemical techniques supported by computational studies based on DFT calculations, was carried out to understand the effects of this treatment on the surface, chemistry and electronic and charge storage properties of NTO. This study underscores the benefits of using urea as a strategy for enhancing the charge storage properties of NTO and thus, unfolding the potential of this material in practical energy storage applications.
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Affiliation(s)
- Sara I. R. Costa
- Department of ChemistryLancaster UniversityLancasterLA1 4YBUK
- The Faraday InstitutionHarwell CampusDidcotOX11 0RAUK
| | - Yong‐Seok Choi
- The Faraday InstitutionHarwell CampusDidcotOX11 0RAUK
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUK
- Thomas Young CentreUniversity College LondonGower StreetLondonWC1E 6BTUK
| | - Alistair J. Fielding
- School of Pharmacy and Biomolecular SciencesLiverpool John Moores UniversityLiverpoolL3 3AFUK
| | - Andrew J. Naylor
- Department of Chemistry—Ångström LaboratoryUppsala UniversityBox 53875121UppsalaSweden
| | - John M. Griffin
- Department of ChemistryLancaster UniversityLancasterLA1 4YBUK
| | - Zdeněk Sofer
- Department of Inorganic ChemistryUniversity of Chemistry and Technology PragueTechnická 516628Prague 6Czech Republic
| | - David O. Scanlon
- The Faraday InstitutionHarwell CampusDidcotOX11 0RAUK
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUK
- Thomas Young CentreUniversity College LondonGower StreetLondonWC1E 6BTUK
- Diamond Light Source Ltd.Diamond HouseHarwell Science and Innovation CampusDidcotOxfordshireOX11 0DEUK
| | - Nuria Tapia‐Ruiz
- Department of ChemistryLancaster UniversityLancasterLA1 4YBUK
- The Faraday InstitutionHarwell CampusDidcotOX11 0RAUK
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37
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Yamamoto T, Oswald IWH, Savory CN, Ohmi T, Koegel AA, Scanlon DO, Kageyama H, Neilson JR. Structure and Optical Properties of Layered Perovskite (MA) 2PbI 2-xBr x(SCN) 2 (0 ≤ x < 1.6). Inorg Chem 2020; 59:17379-17384. [PMID: 33232604 DOI: 10.1021/acs.inorgchem.0c02686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The layered perovskite (MA)2PbI2(SCN)2 (MA = CH3NH3+) is a member of an emerging series of compounds derived from hybrid organic-inorganic perovskites. Here, we successfully synthesized (MA)2PbI2-xBrx(SCN)2 (0 ≤ x < 1.6) by using a solid-state reaction. Despite smaller bromide substitution for iodine, 1% linear expansion along the a axis was observed at x ∼ 0.4 due to a change of the orientation of the SCN- anions. Diffuse reflectance spectra reveal that the optical band gap increases by the bromide substitution, which is supported by the DFT calculations. Curiously, bromine-rich compounds where x ≥ 0.8 are light sensitive, leading to partial decomposition after ∼24 h. This study demonstrates that the layered perovskite (MA)2PbI2(SCN)2 tolerates a wide range of bromide substitution toward tuning the band gap energy.
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Affiliation(s)
- Takafumi Yamamoto
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Yokohama 226-8503, Japan.,Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Iain W H Oswald
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Christopher N Savory
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom.,Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Takuya Ohmi
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Alexandra A Koegel
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - David O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom.,Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, United Kingdom.,Diamond Light Source Ltd., Diamond House, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Hiroshi Kageyama
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan.,CREST, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - James R Neilson
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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38
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Abfalterer A, Shamsi J, Kubicki DJ, Savory CN, Xiao J, Divitini G, Li W, Macpherson S, Gałkowski K, MacManus-Driscoll JL, Scanlon DO, Stranks SD. Colloidal Synthesis and Optical Properties of Perovskite-Inspired Cesium Zirconium Halide Nanocrystals. ACS Mater Lett 2020; 2:1644-1652. [PMID: 33313512 PMCID: PMC7724740 DOI: 10.1021/acsmaterialslett.0c00393] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 10/27/2020] [Indexed: 06/01/2023]
Abstract
Optoelectronic devices based on lead halide perovskites are processed in facile ways, yet are remarkably efficient. There are extensive research efforts investigating lead-free perovskite and perovskite-related compounds, yet there are challenges to synthesize these materials in forms that can be directly integrated into thin film devices rather than as bulk powders. Here, we report on the colloidal synthesis and characterization of lead-free, antifluorite Cs2ZrX6 (X = Cl, Br) nanocrystals that are readily processed into thin films. We use transmission electron microscopy and powder X-ray diffraction measurements to determine their size and structural properties, and solid-state nuclear magnetic resonance measurements reveal the presence of oleate ligand, together with a disordered distribution of Cs surface sites. Density functional theory calculations reveal the band structure and fundamental band gaps of 5.06 and 3.91 eV for Cs2ZrCl6 and Cs2ZrBr6, respectively, consistent with experimental values. Finally, we demonstrate that the Cs2ZrCl6 and Cs2ZrBr6 nanocrystal thin films exhibit tunable, broad white photoluminescence with quantum yields of 45% for the latter, with respective peaks in the blue and green spectral regions and mixed systems exhibiting properties between them. Our work represents a critical step toward the application of lead-free Cs2ZrX6 nanocrystal thin films into next-generation light-emitting applications.
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Affiliation(s)
- Anna Abfalterer
- Cavendish Laboratory,
Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Javad Shamsi
- Cavendish Laboratory,
Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Dominik J. Kubicki
- Cavendish Laboratory,
Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Christopher N. Savory
- Department
of Chemistry and Thomas Young Centre, University
College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - James Xiao
- Cavendish Laboratory,
Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Giorgio Divitini
- Department
of Materials Science & Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Weiwei Li
- Department
of Materials Science & Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Stuart Macpherson
- Cavendish Laboratory,
Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Krzysztof Gałkowski
- Cavendish Laboratory,
Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
- Institute of Physics, Faculty of Physics,
Astronomy and Informatics, Nicolaus Copernicus
University, 5th Grudziądzka
St., 87-100 Toruń, Poland
| | - Judith L. MacManus-Driscoll
- Department
of Materials Science & Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - David O. Scanlon
- Department
of Chemistry and Thomas Young Centre, University
College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Diamond
Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Samuel D. Stranks
- Cavendish Laboratory,
Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
- Department of Chemical Engineering and
Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, United Kingdom
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39
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Crovetto A, Xing Z, Fischer M, Nielsen R, Savory CN, Rindzevicius T, Stenger N, Scanlon DO, Chorkendorff I, Vesborg PCK. Experimental and First-Principles Spectroscopy of Cu 2SrSnS 4 and Cu 2BaSnS 4 Photoabsorbers. ACS Appl Mater Interfaces 2020; 12:50446-50454. [PMID: 33108169 DOI: 10.1021/acsami.0c14578] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cu2BaSnS4 (CBTS) and Cu2SrSnS4 (CSTS) semiconductors have been recently proposed as potential wide band gap photovoltaic absorbers. Although several measurements indicate that they are less affected by band tailing than their parent compound Cu2ZnSnS4, their photovoltaic efficiencies are still low. To identify possible issues, we characterize CBTS and CSTS in parallel by a variety of spectroscopic methods complemented by first-principles calculations. Two main problems are identified in both materials. The first is the existence of deep defect transitions in low-temperature photoluminescence, pointing to a high density of bulk recombination centers. The second is their low electron affinity, which emphasizes the need for an alternative heterojunction partner and electron contact. We also find a tendency for downward band bending at the surface of both materials. In CBTS, this effect is sufficiently large to cause carrier-type inversion, which may enhance carrier separation and mitigate interface recombination. Optical absorption at room temperature is exciton-enhanced in both CBTS and CSTS. Deconvolution of excitonic effects yields band gaps that are about 100 meV higher than previous estimates based on Tauc plots. Although the two investigated materials are remarkably similar in an idealized, defect-free picture, the present work points to CBTS as a more promising absorber than CSTS for tandem photovoltaics.
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Affiliation(s)
- Andrea Crovetto
- SurfCat, DTU Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
- Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 14109 Berlin, Germany
| | - Zongda Xing
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, U.K
| | - Moritz Fischer
- DTU Fotonik, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
- Center for Nanostructured Graphene (CNG), Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Rasmus Nielsen
- SurfCat, DTU Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Christopher N Savory
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, U.K
| | - Tomas Rindzevicius
- DTU Health Technology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Nicolas Stenger
- DTU Fotonik, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
- Center for Nanostructured Graphene (CNG), Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - David O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, U.K
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K
| | - Ib Chorkendorff
- SurfCat, DTU Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Peter C K Vesborg
- SurfCat, DTU Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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40
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Williamson BA, Limburn GJ, Watson GW, Hyett G, Scanlon DO. Computationally Driven Discovery of Layered Quinary Oxychalcogenides: Potential p-Type Transparent Conductors? Matter 2020; 3:759-781. [PMID: 34708195 PMCID: PMC8523359 DOI: 10.1016/j.matt.2020.05.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/12/2020] [Accepted: 05/20/2020] [Indexed: 05/12/2023]
Abstract
n-type transparent conductors (TCs) are key materials in the modern optoelectronics industry. Despite years of research, the development of a high-performance p-type TC has lagged far behind that of its n-type counterparts, delaying the advent of "transparent electronics"-based p-n junctions. Here, we propose the layered oxysulfide [Cu2S2][Sr3Sc2O5] as a structural motif for discovering p-type TCs. We have used density functional theory to screen 24 compositions based on this motif in terms of their thermodynamic and dynamic stability and their electronic structure, thus predicting two p-type TCs and eight other stable systems with semiconductor properties. Following our predictions, we have successfully synthesized our best candidate p-type TC, [Cu2S2][Ba3Sc2O5], which displays structural and optical properties that validate our computational models. It is expected that the design principles emanating from this analysis will move the field closer to the realization of a high figure-of-merit p-type TC.
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Affiliation(s)
- Benjamin A.D. Williamson
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, UK
- Corresponding author
| | - Gregory J. Limburn
- Department of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Graeme W. Watson
- School of Chemistry and CRANN, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Geoffrey Hyett
- Department of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
- Corresponding author
| | - David O. Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
- Thomas Young Centre, University College London, Gower Street, London WC1E 6BT, UK
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
- Corresponding author
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41
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Rahim W, Skelton JM, Savory CN, Evans IR, Evans JSO, Walsh A, Scanlon DO. Polymorph exploration of bismuth stannate using first-principles phonon mode mapping. Chem Sci 2020; 11:7904-7909. [PMID: 34909139 PMCID: PMC8617592 DOI: 10.1039/d0sc02995e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/02/2020] [Indexed: 11/21/2022] Open
Abstract
Accurately modelling polymorphism in crystalline solids remains a key challenge in computational chemistry. In this work, we apply a theoretically-rigorous phonon mode-mapping approach to understand the polymorphism in the ternary metal oxide Bi2Sn2O7. Starting from the high-temperature cubic pyrochlore aristotype, we systematically explore the structural potential-energy surface and recover the two known low-temperature phases alongside three new metastable phases, together with the transition pathways connecting them. This first-principles lattice-dynamics method is completely general and provides a practical means to identify and characterise the stable polymorphs and phase transitions in materials with complex crystal structures.
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Affiliation(s)
- Warda Rahim
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
- Thomas Young Centre, University College London Gower Street London WC1E 6BT UK
| | - Jonathan M Skelton
- Department of Chemistry, University of Manchester Oxford Road Manchester M13 9PL UK
| | - Christopher N Savory
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
- Thomas Young Centre, University College London Gower Street London WC1E 6BT UK
| | - Ivana R Evans
- Department of Chemistry, University Science Site, Durham University South Road Durham DH1 3LE UK
| | - John S O Evans
- Department of Chemistry, University Science Site, Durham University South Road Durham DH1 3LE UK
| | - Aron Walsh
- Department of Materials, Imperial College London Exhibition Road London SW7 2AZ UK
- Department of Materials Science and Engineering, Yonsei University Seoul 03722 Korea
| | - David O Scanlon
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
- Thomas Young Centre, University College London Gower Street London WC1E 6BT UK
- Diamond Light Source Ltd. Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE UK
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42
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Davies DW, Morgan BJ, Scanlon DO, Walsh A. Low-cost descriptors of electrostatic and electronic contributions to anion redox activity in batteries. IOPSciNotes 2020. [DOI: 10.1088/2633-1357/ab9750] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract
Conventional battery cathodes are limited by the redox capacity of the transition metal components. For example, the delithiation of LiCoO2 involves the formal oxidation from Co(III) to Co(IV). Enhanced capacities can be achieved if the anion also contributes to reversible oxidation. The origins of redox activity in crystals are difficult to quantify from experimental measurements or first-principles materials modelling. We present practical procedures to describe the electrostatic (Madelung potential) and electronic (integrated density of states) contributions, which are applied to the LiMO2 and Li2
MO3 (M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au) model systems. We discuss how such descriptors could be integrated in a materials design workflow.
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43
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Abstract
The corrosion and oxidation of actinide metals, leading to the formation of metal-oxide surface layers with the catalytic evolution of hydrogen, impacts the management of nuclear materials. Here, the interaction of hydrogen with actinide dioxide (AnO2, An = U, Np, or Pu) (011) surfaces by Hubbard corrected density functional theory (PBEsol+U) has been studied, including spin-orbit interactions and non-collinear 3k anti-ferromagnetic behavior. The actinide dioxides crystalize in the fluorite-type structure, and although the (111) surface dominates the crystal morphology, the (011) surface energetics may lead to more significant interaction with hydrogen. The dissociative adsorption of hydrogen on the UO2 (0.44 eV), NpO2 (-0.47 eV), and PuO2 (-1.71 eV) (011) surfaces has been calculated. It is found that hydrogen dissociates on the PuO2 (011) surface; however, UO2 (011) and NpO2 (011) surfaces are relatively inert. Recombination of hydrogen ions is likely to occur on the UO2 (011) and NpO2 (011) surfaces, whereas hydroxide formation is shown to occur on the PuO2 (011) surface, which distorts the surface structure.
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Affiliation(s)
- James T Pegg
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Ashley E Shields
- Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, Tennessee 37831, USA
| | - Mark T Storr
- Atomic Weapons Establishment (AWE) Plc, Aldermaston, Reading, Berkshire RG7 4PR, United Kingdom
| | - David O Scanlon
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Nora H de Leeuw
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
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44
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Murgatroyd PE, Smiles MJ, Savory CN, Shalvey TP, Swallow JEN, Fleck N, Robertson CM, Jäckel F, Alaria J, Major JD, Scanlon DO, Veal TD. GeSe: Optical Spectroscopy and Theoretical Study of a van der Waals Solar Absorber. Chem Mater 2020; 32:3245-3253. [PMID: 32308255 PMCID: PMC7161679 DOI: 10.1021/acs.chemmater.0c00453] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/13/2020] [Indexed: 06/11/2023]
Abstract
The van der Waals material GeSe is a potential solar absorber, but its optoelectronic properties are not yet fully understood. Here, through a combined theoretical and experimental approach, the optoelectronic and structural properties of GeSe are determined. A fundamental absorption onset of 1.30 eV is found at room temperature, close to the optimum value according to the Shockley-Queisser detailed balance limit, in contrast to previous reports of an indirect fundamental transition of 1.10 eV. The measured absorption spectra and first-principles joint density of states are mutually consistent, both exhibiting an additional distinct onset ∼0.3 eV above the fundamental absorption edge. The band gap values obtained from first-principles calculations converge, as the level of theory and corresponding computational cost increases, to 1.33 eV from the quasiparticle self-consistent GW method, including the solution to the Bethe-Salpeter equation. This agrees with the 0 K value determined from temperature-dependent optical absorption measurements. Relaxed structures based on hybrid functionals reveal a direct fundamental transition in contrast to previous reports. The optoelectronic properties of GeSe are resolved with the system described as a direct semiconductor with a 1.30 eV room temperature band gap. The high level of agreement between experiment and theory encourages the application of this computational methodology to other van der Waals materials.
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Affiliation(s)
- Philip
A. E. Murgatroyd
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
| | - Matthew J. Smiles
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
| | - Christopher N. Savory
- Department
of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
| | - Thomas P. Shalvey
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
| | - Jack E. N. Swallow
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
| | - Nicole Fleck
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
| | - Craig M. Robertson
- Department
of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.
| | - Frank Jäckel
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
| | - Jonathan Alaria
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
| | - Jonathan D. Major
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
| | - David O. Scanlon
- Department
of Chemistry, University College London, Christopher Ingold Building, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
- Diamond
Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K.
| | - Tim D. Veal
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
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45
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Alotaibi A, Williamson BAD, Sathasivam S, Kafizas A, Alqahtani M, Sotelo-Vazquez C, Buckeridge J, Wu J, Nair SP, Scanlon DO, Parkin IP. Enhanced Photocatalytic and Antibacterial Ability of Cu-Doped Anatase TiO 2 Thin Films: Theory and Experiment. ACS Appl Mater Interfaces 2020; 12:15348-15361. [PMID: 32109038 PMCID: PMC7146757 DOI: 10.1021/acsami.9b22056] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 02/28/2020] [Indexed: 05/12/2023]
Abstract
Multifunctional thin films which can display both photocatalytic and antibacterial activity are of great interest industrially. Here, for the first time, we have used aerosol-assisted chemical vapor deposition to deposit highly photoactive thin films of Cu-doped anatase TiO2 on glass substrates. The films displayed much enhanced photocatalytic activity relative to pure anatase and showed excellent antibacterial (vs Staphylococcus aureus and Escherichia coli) ability. Using a combination of transient absorption spectroscopy, photoluminescence measurements, and hybrid density functional theory calculations, we have gained nanoscopic insights into the improved properties of the Cu-doped TiO2 films. Our analysis has highlighted that the interactions between substitutional and interstitial Cu in the anatase lattice can explain the extended exciton lifetimes observed in the doped samples and the enhanced UV photoactivities observed.
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Affiliation(s)
- Abdullah
M. Alotaibi
- Materials
Chemistry Centre, Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- The
National Centre for Building and Construction Technology, King Abdulaziz City for Science and Technology (KACST), Riyadh 11442-6086, Saudi Arabia
| | - Benjamin A. D. Williamson
- Department
of Chemistry, Christopher Ingold Building, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
| | - Sanjayan Sathasivam
- Materials
Chemistry Centre, Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | - Andreas Kafizas
- Grantham Institute,
Imperial College
London, Exhibition Road, London SW7 2AZ, U.K.
| | - Mahdi Alqahtani
- Electronic
& Electrical Engineering, University
College London, Torrington
Place, London WC1E 7JE, U.K.
- Materials
Science Research Institute, King Abdulaziz
City for Science and Technology (KACST), Riyadh 11442-6086, Saudi Arabia
| | - Carlos Sotelo-Vazquez
- Materials
Chemistry Centre, Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | - John Buckeridge
- School
of Engineering, London South Bank University, 103 Borough Road, London SE1 0AA, U.K.
| | - Jiang Wu
- Electronic
& Electrical Engineering, University
College London, Torrington
Place, London WC1E 7JE, U.K.
- University
of Electronic Science and Technology of China, North Jianshe Road, Chengdu 610054, China
| | - Sean P. Nair
- Department
of Microbial Diseases, UCL Eastman Dental
Institute, 256 Gray’s
Inn Road, London WC1X 8LD, U.K.
| | - David O. Scanlon
- Department
of Chemistry, Christopher Ingold Building, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, U.K.
- Diamond Light Source Ltd., Diamond House, Harwell Science and
Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K.
| | - Ivan P. Parkin
- Materials
Chemistry Centre, Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
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46
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Williamson BD, Featherstone TJ, Sathasivam SS, Swallow JEN, Shiel H, Jones LAH, Smiles MJ, Regoutz A, Lee TL, Xia X, Blackman C, Thakur PK, Carmalt CJ, Parkin IP, Veal TD, Scanlon DO. Resonant Ta Doping for Enhanced Mobility in Transparent Conducting SnO 2. Chem Mater 2020; 32:1964-1973. [PMID: 32296264 PMCID: PMC7147269 DOI: 10.1021/acs.chemmater.9b04845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/17/2020] [Indexed: 05/16/2023]
Abstract
Transparent conducting oxides (TCOs) are ubiquitous in modern consumer electronics. SnO2 is an earth abundant, cheaper alternative to In2O3 as a TCO. However, its performance in terms of mobilities and conductivities lags behind that of In2O3. On the basis of the recent discovery of mobility and conductivity enhancements in In2O3 from resonant dopants, we use a combination of state-of-the-art hybrid density functional theory calculations, high resolution photoelectron spectroscopy, and semiconductor statistics modeling to understand what is the optimal dopant to maximize performance of SnO2-based TCOs. We demonstrate that Ta is the optimal dopant for high performance SnO2, as it is a resonant dopant which is readily incorporated into SnO2 with the Ta 5d states sitting ∼1.4 eV above the conduction band minimum. Experimentally, the band edge electron effective mass of Ta doped SnO2 was shown to be 0.23m 0, compared to 0.29m 0 seen with conventional Sb doping, explaining its ability to yield higher mobilities and conductivities.
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Affiliation(s)
- Benjamin
A. D. Williamson
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, United
Kingdom
| | - Thomas J. Featherstone
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, United Kingdom
| | - Sanjayan S. Sathasivam
- Materials
Research Centre, Chemistry Department, University
College London,, London WC1H 0AJ, United Kingdom
| | - Jack E. N. Swallow
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, United Kingdom
| | - Huw Shiel
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, United Kingdom
| | - Leanne A. H. Jones
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, United Kingdom
| | - Matthew J. Smiles
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, United Kingdom
| | - Anna Regoutz
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Tien-Lin Lee
- Diamond
Light Source Ltd., Diamond House,
Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11
0DE, United Kingdom
| | - Xueming Xia
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Christopher Blackman
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Pardeep K. Thakur
- Diamond
Light Source Ltd., Diamond House,
Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11
0DE, United Kingdom
| | - Claire J. Carmalt
- Materials
Research Centre, Chemistry Department, University
College London,, London WC1H 0AJ, United Kingdom
| | - Ivan P. Parkin
- Materials
Research Centre, Chemistry Department, University
College London,, London WC1H 0AJ, United Kingdom
| | - Tim D. Veal
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, United Kingdom
- E-mail:
| | - David O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, United
Kingdom
- E-mail:
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47
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Abstract
Metal oxides can act as insulators, semiconductors, or metals depending on their chemical composition and crystal structure. Metal oxide semiconductors, which support equilibrium populations of electron and hole charge carriers, have widespread applications including batteries, solar cells, and display technologies. It is often difficult to predict in advance whether these materials will exhibit localized or delocalized charge carriers upon oxidation or reduction. We combine data from first-principles calculations of the electronic structure and dielectric response of 214 metal oxides to predict the energetic driving force for carrier localization and transport. We assess descriptors based on the carrier effective mass, static polaron binding energy, and Fröhlich electron-phonon coupling. Numerical analysis allows us to assign p- and n-type transport of a metal oxide to three classes: (i) band transport with high mobility; (ii) small polaron transport with low mobility; and (iii) intermediate behavior. The results of this classification agree with observations regarding carrier dynamics and lifetimes and are used to predict 10 candidate p-type oxides.
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Affiliation(s)
- Daniel W Davies
- Department of Materials , Imperial College London , London SW7 2AZ , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
| | - Christopher N Savory
- Department of Chemistry and Thomas Young Centre , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
| | - Jarvist M Frost
- Department of Physics , Imperial College London , London SW7 2AZ , United Kingdom
| | - David O Scanlon
- Department of Chemistry and Thomas Young Centre , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
- Diamond Light Source Ltd. , Diamond House, Harwell Science and Innovation Campus, Didcot , Oxfordshire OX11 0DE , United Kingdom
| | - Benjamin J Morgan
- Department of Chemistry , University of Bath , Claverton Down, Bath BA2 7AY , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
| | - Aron Walsh
- Department of Materials , Imperial College London , London SW7 2AZ , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
- Department of Materials Science and Engineering , Yonsei University , Seoul 03722 , Korea
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48
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Abstract
Metal oxides can act as insulators, semiconductors, or metals depending on their chemical composition and crystal structure. Metal oxide semiconductors, which support equilibrium populations of electron and hole charge carriers, have widespread applications including batteries, solar cells, and display technologies. It is often difficult to predict in advance whether these materials will exhibit localized or delocalized charge carriers upon oxidation or reduction. We combine data from first-principles calculations of the electronic structure and dielectric response of 214 metal oxides to predict the energetic driving force for carrier localization and transport. We assess descriptors based on the carrier effective mass, static polaron binding energy, and Fröhlich electron-phonon coupling. Numerical analysis allows us to assign p- and n-type transport of a metal oxide to three classes: (i) band transport with high mobility; (ii) small polaron transport with low mobility; and (iii) intermediate behavior. The results of this classification agree with observations regarding carrier dynamics and lifetimes and are used to predict 10 candidate p-type oxides.
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Affiliation(s)
- Daniel W Davies
- Department of Materials , Imperial College London , London SW7 2AZ , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
| | - Christopher N Savory
- Department of Chemistry and Thomas Young Centre , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
| | - Jarvist M Frost
- Department of Physics , Imperial College London , London SW7 2AZ , United Kingdom
| | - David O Scanlon
- Department of Chemistry and Thomas Young Centre , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
- Diamond Light Source Ltd. , Diamond House, Harwell Science and Innovation Campus, Didcot , Oxfordshire OX11 0DE , United Kingdom
| | - Benjamin J Morgan
- Department of Chemistry , University of Bath , Claverton Down, Bath BA2 7AY , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
| | - Aron Walsh
- Department of Materials , Imperial College London , London SW7 2AZ , United Kingdom
- The Faraday Institution , Quad One, Harwell Campus, Didcot OX11 0RA , United Kingdom
- Department of Materials Science and Engineering , Yonsei University , Seoul 03722 , Korea
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49
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Karim MS, Ganose AM, Pieters L, Winnie Leung WW, Wade J, Zhang L, Scanlon DO, Palgrave RG. Anion Distribution, Structural Distortion, and Symmetry-Driven Optical Band Gap Bowing in Mixed Halide Cs 2SnX 6 Vacancy Ordered Double Perovskites. Chem Mater 2019; 31:9430-9444. [PMID: 32116409 PMCID: PMC7046317 DOI: 10.1021/acs.chemmater.9b03267] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 11/04/2019] [Indexed: 06/01/2023]
Abstract
Mixed anion compounds in the Fm3̅m vacancy ordered perovskite structure were synthesized and characterized experimentally and computationally with a focus on compounds where A = Cs+. Pure anion Cs2SnX6 compounds were formed with X = Cl, Br, and I using a room temperature solution phase method. Mixed anion compounds were formed as solid solutions of Cs2SnCl6 and Cs2SnBr6 and a second series from Cs2SnBr6 and Cs2SnI6. Single phase structures formed across the entirety of both composition series with no evidence of long-range anion ordering observed by diffraction. A distortion of the cubic A2BX6 structure was identified in which the spacing of the BX6 octahedra changes to accommodate the A site cation without reduction of overall symmetry. Optical band gap values varied with anion composition between 4.89 eV in Cs2SnCl6 to 1.35 eV in Cs2SnI6 but proved highly nonlinear with changes in composition. In mixed halide compounds, it was found that lower energy optical transitions appeared that were not present in the pure halide compounds, and this was attributed to lowering of the local symmetry within the tin halide octahedra. The electronic structure was characterized by photoemission spectroscopy, and Raman spectroscopy revealed vibrational modes in the mixed halide compounds that could be assigned to particular mixed halide octahedra. This analysis was used to determine the distribution of octahedra types in mixed anion compounds, which was found to be consistent with a near-random distribution of halide anions throughout the structure, although some deviations from random halide distribution were noted in mixed iodide-bromide compounds, where the larger iodide anions preferentially adopted trans configurations.
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Affiliation(s)
- Maham
M. S. Karim
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Alex M. Ganose
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Diamond
House, Harwell Science and Innovation Campus, Diamond Light Source Ltd., Didcot, Oxfordshire OX11 0DE, United Kingdom
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, United
Kingdom
| | - Laura Pieters
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - W. W. Winnie Leung
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Jessica Wade
- Department
of Physics and Centre for Plastic Electronics, Imperial College, London SW7 2AZ, United Kingdom
| | - Lina Zhang
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - David O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
- Diamond
House, Harwell Science and Innovation Campus, Diamond Light Source Ltd., Didcot, Oxfordshire OX11 0DE, United Kingdom
- Thomas
Young Centre, University College London, Gower Street, London WC1E 6BT, United
Kingdom
| | - Robert G. Palgrave
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
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50
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Yang H, Yang JY, Savory CN, Skelton JM, Morgan BJ, Scanlon DO, Walsh A. Highly Anisotropic Thermal Transport in LiCoO 2. J Phys Chem Lett 2019; 10:5552-5556. [PMID: 31475830 DOI: 10.1021/acs.jpclett.9b02073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
LiCoO2 is the prototypical cathode in lithium-ion batteries. Its crystal structure consists of Li+ and CoO2- layers that alternate along the hexagonal ⟨0001⟩ axis. It is well established that the ionic and electronic conduction are anisotropic, but little is known regarding the heat transport. We analyze the phonon dispersion and lifetimes using anharmonic lattice dynamics based on quantum-chemical force constants. Around room temperature, the thermal conductivity in the hexagonal ab plane of the layered cathode is ∼6 times higher than that along the c axis. An upper limit to the average thermal conductivity at T = 300 K of 38.5 W m-1 K-1 is set by short phonon lifetimes associated with anharmonic interactions within the octahedral face-sharing CoO2- network. Observations of conductivity <10 W m-1 K-1 can be understood by additional scattering channels including grain boundaries in polycrystalline samples. The impact on thermal processes in lithium-ion batteries is discussed.
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Affiliation(s)
- Hui Yang
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , U.K
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus , Didcot OX11 0RA , U.K
| | - Jia-Yue Yang
- School of Energy and Power Engineering , Shandong University , Qingdao 266237 , China
| | - Christopher N Savory
- University College London , Department of Chemistry and Thomas Young Centre , 20 Gordon Street , London WC1H 0AJ , U.K
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus , Didcot OX11 0RA , U.K
| | - Jonathan M Skelton
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , U.K
| | - Benjamin J Morgan
- Department of Chemistry , University of Bath , Claverton Down , Bath BA2 7AY , U.K
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus , Didcot OX11 0RA , U.K
| | - David O Scanlon
- University College London , Department of Chemistry and Thomas Young Centre , 20 Gordon Street , London WC1H 0AJ , U.K
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus , Didcot , Oxfordshire OX11 0DE , U.K
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus , Didcot OX11 0RA , U.K
| | - Aron Walsh
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , U.K
- Department of Materials Science and Engineering , Yonsei University , Seoul 03722 , Korea
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus , Didcot OX11 0RA , U.K
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