1
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Erbing A, Philippe B, Park BW, Cappel UB, Rensmo H, Odelius M. Spatial microheterogeneity in the valence band of mixed halide hybrid perovskite materials. Chem Sci 2022; 13:9285-9294. [PMID: 36093010 PMCID: PMC9384462 DOI: 10.1039/d2sc03440a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 07/18/2022] [Indexed: 11/23/2022] Open
Abstract
The valence band of lead halide hybrid perovskites with a mixed I/Br composition is investigated using electronic structure calculations and complementarily probed with hard X-ray photoelectron spectroscopy. In the latter, we used high photon energies giving element sensitivity to the heavy lead and halide ions and we observe distinct trends in the valence band as a function of the I : Br ratio. Through electronic structure calculations, we show that the spectral trends with overall composition can be understood in terms of variations in the local environment of neighboring halide ions. From the computational model supported by the experimental evidence, a picture of the microheterogeneity in the valence band maximum emerges. The microheterogeneity in the valence band suggests that additional charge transport mechanisms might be active in lead mixed halide hybrid perovskites, which could be described in terms of percolation pathways.
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Affiliation(s)
- Axel Erbing
- Department of Physics, Stockholm University, AlbaNova University Center SE-106 91 Stockholm Sweden +46 8 5537 8601 +46 8 5537 8713
| | - Bertrand Philippe
- Department of Physics and Astronomy, Uppsala University Box 516 SE-751 20 Uppsala Sweden
| | - Byung-Wook Park
- Department of Physics and Astronomy, Uppsala University Box 516 SE-751 20 Uppsala Sweden
- Department of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology 50 UNIST-gil, Eonyang-eup, Ulju-gun Ulsan 44919 Korea
| | - Ute B Cappel
- Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology SE-100 44 Stockholm Sweden
| | - Håkan Rensmo
- Department of Physics and Astronomy, Uppsala University Box 516 SE-751 20 Uppsala Sweden
| | - Michael Odelius
- Department of Physics, Stockholm University, AlbaNova University Center SE-106 91 Stockholm Sweden +46 8 5537 8601 +46 8 5537 8713
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2
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Kim BG, Jang W, Wang DH. Facile NiO x Sol-Gel Synthesis Depending on Chain Length of Various Solvents without Catalyst for Efficient Hole Charge Transfer in Perovskite Solar Cells. Polymers (Basel) 2018; 10:polym10111227. [PMID: 30961152 PMCID: PMC6290588 DOI: 10.3390/polym10111227] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 11/01/2018] [Accepted: 11/01/2018] [Indexed: 11/16/2022] Open
Abstract
Nickel oxide (NiOx)–based perovskite solar cells (PSCs) have recently gained considerable interest, and exhibit above 20% photovoltaic efficiency. However, the reported syntheses of NiOx sol-gel used toxic chemicals for the catalysts during synthesis, which resulted in a high-temperature annealing requirement to remove the organic catalysts (ligands). Herein, we report a facile “NiOx sol-gel depending on the chain length of various solvents” method that eschews toxic catalysts, to confirm the effect of different types of organic solvents on NiOx synthesis. The optimized conditions of the method resulted in better morphology and an increase in the crystallinity of the perovskite layer. Furthermore, the use of the optimized organic solvent improved the absorbance of the photoactive layer in the PSC device. To compare the electrical properties, a PSC was prepared with a p-i-n structure, and the optimized divalent alcohol-based NiOx as the hole transport layer. This improved the charge transport compared with that for the typical 1,2-ethanediol (ethylene glycol) used in earlier studies. Finally, the optimized solvent-based NiOx enhanced device performance by increasing the short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF), compared with those of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)–based devices.
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Affiliation(s)
- Byung Gi Kim
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-Ro, Dongjak-gu, Seoul 06974, Korea.
| | - Woongsik Jang
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-Ro, Dongjak-gu, Seoul 06974, Korea.
| | - Dong Hwan Wang
- School of Integrative Engineering, Chung-Ang University, 84 Heukseok-Ro, Dongjak-gu, Seoul 06974, Korea.
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3
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Rajagopal A, Yao K, Jen AKY. Toward Perovskite Solar Cell Commercialization: A Perspective and Research Roadmap Based on Interfacial Engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1800455. [PMID: 29883006 DOI: 10.1002/adma.201800455] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 03/07/2018] [Indexed: 05/17/2023]
Abstract
High-efficiency and low-cost perovskite solar cells (PVKSCs) are an ideal candidate for addressing the scalability challenge of solar-based renewable energy. The dynamically evolving research field of PVKSCs has made immense progress in solving inherent challenges and capitalizing on their unique structure-property-processing-performance traits. This review offers a unique outlook on the paths toward commercialization of PVKSCs from the interfacial engineering perspective, relevant to both specialists and nonspecialists in the field through a brief introduction of the background of the field, current state-of-the-art evolution, and future research prospects. The multifaceted role of interfaces in facilitating PVKSC development is explained. Beneficial impacts of diverse charge-transporting materials and interfacial modifications are summarized. In addition, the role of interfaces in improving efficiency and stability for all emerging areas of PVKSC design are also evaluated. The authors' integral contributions in this area are highlighted on all fronts. Finally, future research opportunities for interfacial material development and applications along with scalability-durability-sustainability considerations pivotal for facilitating laboratory to industry translation are presented.
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Affiliation(s)
- Adharsh Rajagopal
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Kai Yao
- Institute of Photovoltaics, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031, China
| | - Alex K-Y Jen
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong
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4
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Yuan H, Debroye E, Bladt E, Lu G, Keshavarz M, Janssen KPF, Roeffaers MBJ, Bals S, Sargent EH, Hofkens J. Imaging Heterogeneously Distributed Photo-Active Traps in Perovskite Single Crystals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1705494. [PMID: 29457290 DOI: 10.1002/adma.201705494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/04/2018] [Indexed: 05/25/2023]
Abstract
Organic-inorganic halide perovskites (OIHPs) have demonstrated outstanding energy conversion efficiency in solar cells and light-emitting devices. In spite of intensive developments in both materials and devices, electronic traps and defects that significantly affect their device properties remain under-investigated. Particularly, it remains challenging to identify and to resolve traps individually at the nanoscopic scale. Here, photo-active traps (PATs) are mapped over OIHP nanocrystal morphology of different crystallinity by means of correlative optical differential super-resolution localization microscopy (Δ-SRLM) and electron microscopy. Stochastic and monolithic photoluminescence intermittency due to individual PATs is observed on monocrystalline and polycrystalline OIHP nanocrystals. Δ-SRLM reveals a heterogeneous PAT distribution across nanocrystals and determines the PAT density to be 1.3 × 1014 and 8 × 1013 cm-3 for polycrystalline and for monocrystalline nanocrystals, respectively. The higher PAT density in polycrystalline nanocrystals is likely related to an increased defect density. Moreover, monocrystalline nanocrystals that are prepared in an oxygen- and moisture-free environment show a similar PAT density as that prepared at ambient conditions, excluding oxygen or moisture as chief causes of PATs. Hence, it is concluded that the PATs come from inherent structural defects in the material, which suggests that the PAT density can be reduced by improving crystalline quality of the material.
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Affiliation(s)
- Haifeng Yuan
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Elke Debroye
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Eva Bladt
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium
| | - Gang Lu
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, 211816, Nanjing, China
| | - Masoumeh Keshavarz
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Kris P F Janssen
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Maarten B J Roeffaers
- Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Sara Bals
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Johan Hofkens
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
- RIES, Hokkaido University, N20W10, Kita-Ward Sapporo, 001-0020, Japan
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5
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Sosorev AY, Godovsky DY, Paraschuk DY. Hot kinetic model as a guide to improve organic photovoltaic materials. Phys Chem Chem Phys 2018; 20:3658-3671. [DOI: 10.1039/c7cp06158g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The model yields that the most promising ways to increase the OSC performance are decreasing the reorganization energy, increasing the dielectric permittivity and enhancing the charge delocalization.
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Affiliation(s)
- Andrey Yu. Sosorev
- Faculty of Physics and International Laser Center
- M.V. Lomonosov Moscow State University
- Moscow 119991
- Russia
| | - Dmitry Yu. Godovsky
- Institute of Elementoorganic Compounds
- Russian Academy of Science
- Moscow
- Russia
| | - Dmitry Yu. Paraschuk
- Faculty of Physics and International Laser Center
- M.V. Lomonosov Moscow State University
- Moscow 119991
- Russia
- Enikolopov Institute of Synthetic Polymeric Materials
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6
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Oliveira MC, Ribeiro RAP, Gracia L, de Lazaro SR, de Assis M, Oliva M, Rosa ILV, Gurgel MFDC, Longo E, Andrés J. Experimental and theoretical study of the energetic, morphological, and photoluminescence properties of CaZrO3:Eu3+. CrystEngComm 2018. [DOI: 10.1039/c8ce00964c] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we present a combined experimental and theoretical study of the geometry, electronic structure, morphology, and photoluminescence properties of CaZrO3:Eu3+ materials.
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Affiliation(s)
- Marisa Carvalho Oliveira
- Department of Analytical and Physical Chemistry
- Universitat Jaume I
- Castelló E-12071
- Spain
- CDMF-UFSCar
| | | | - Lourdes Gracia
- Department of Physical Chemistry
- Universitat de Valencia
- Burjassot E-46100
- Spain
| | - Sergio R. de Lazaro
- Department of Chemistry
- Universidade Estadual de Ponta Grossa
- Ponta Grossa
- Brazil
| | - Marcelo de Assis
- CDMF-UFSCar
- Universidade Federal de São Carlos
- 13565-905 São Carlos
- Brazil
| | - Mónica Oliva
- Department of Analytical and Physical Chemistry
- Universitat Jaume I
- Castelló E-12071
- Spain
| | | | | | - Elson Longo
- CDMF-UFSCar
- Universidade Federal de São Carlos
- 13565-905 São Carlos
- Brazil
| | - Juan Andrés
- Department of Analytical and Physical Chemistry
- Universitat Jaume I
- Castelló E-12071
- Spain
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7
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Merdasa A, Gerhard M, Louis B, Li J, Dobrovolsky A, Tian Y, Hofkens J, Camacho R, Unger E, Scheblykin IG. Non-radiative processes in metal halide perovskite semiconductors probed by photoluminescence microscopy. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201819002011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Organo metal halide perovskites are solution processed semiconductors that recently attracted a great attention. They possess a rather “soft” and (photo) chemically active solid structure allowing for ion migration and other mass diffusion processes. This is a likely reason why non-radiative recombination centres in these materials are activated and deactivated on relatively slow time-scales. This dynamics reveals as photoluminescence (PL) fluctuations (blinking) of individual microcrystals and local areas of films and allows for application of a broad range of single molecule spectroscopy methods including optical super-resolution. Studying PL blinking resolves properties of individual non-radiative centres and helps to unravel their chemical nature.
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8
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Reisch A, Trofymchuk K, Runser A, Fleith G, Rawiso M, Klymchenko AS. Tailoring Fluorescence Brightness and Switching of Nanoparticles through Dye Organization in the Polymer Matrix. ACS APPLIED MATERIALS & INTERFACES 2017; 9:43030-43042. [PMID: 29185702 DOI: 10.1021/acsami.7b12292] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Fluorescent nanoparticles (NPs) help to increase spatial and temporal resolution in bioimaging. Advanced microscopy techniques require very bright NPs that exhibit either stable emission for single-particle tracking or complete on/off switching (blinking) for super-resolution imaging. Here, ultrabright dye-loaded polymer NPs with controlled switching properties are developed. To this aim, the salt of a dye (rhodamine B octadecyl ester) with a hydrophobic counterion (fluorinated tetraphenylborate) is encapsulated at very high concentrations up to 30 wt % in NPs made of poly(lactic-co-glycolic acid) (PLGA), poly(methyl methacrylate) (PMMA), and polycaprolactone (PCL) through nanoprecipitation. The obtained 35 nm NPs are nearly 100 times brighter than quantum dots. The nature of the polymer is found to define the collective behavior of the encapsulated dyes so that NPs containing thousands of dyes exhibit either whole particle blinking, for PLGA, or stable emission, for PMMA and PCL. Fluorescence anisotropy measurements together with small-angle X-ray scattering experiments suggest that in less hydrophobic PLGA, dyes tend to cluster, whereas in more hydrophobic PMMA and PCL, dyes are dispersed within the matrix, thus altering the switching behavior of NPs. Experiments using a perylene diimide derivative show a similar effect of the polymer nature. The resulting fluorescent NPs are suitable for a wide range of imaging applications from tracking to super-resolution imaging. The findings on the organization of the load innside NPs will have impact on the development of materials for applications ranging from photovoltaics to drug delivery.
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Affiliation(s)
- Andreas Reisch
- Laboratoire de Biophotonique et Pharmacologie, UMR CNRS 7213, Université de Strasbourg , 74 route du Rhin, 67401 Illkirch Cedex, France
| | - Kateryna Trofymchuk
- Laboratoire de Biophotonique et Pharmacologie, UMR CNRS 7213, Université de Strasbourg , 74 route du Rhin, 67401 Illkirch Cedex, France
| | - Anne Runser
- Laboratoire de Biophotonique et Pharmacologie, UMR CNRS 7213, Université de Strasbourg , 74 route du Rhin, 67401 Illkirch Cedex, France
| | - Guillaume Fleith
- Institut Charles Sadron (CNRS-UdS) , 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - Michel Rawiso
- Institut Charles Sadron (CNRS-UdS) , 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - Andrey S Klymchenko
- Laboratoire de Biophotonique et Pharmacologie, UMR CNRS 7213, Université de Strasbourg , 74 route du Rhin, 67401 Illkirch Cedex, France
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9
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Aphrham S, Pan Q, Zaccarine SF, Felter KM, Thieme J, van den Nieuwenhuijzen KJH, Ten Elshof JE, Huijser A. Effect of Water Addition during Preparation on the Early-Time Photodynamics of CH 3 NH 3 PbI 3 Perovskite Layers. Chemphyschem 2017; 18:3320-3324. [PMID: 29024345 DOI: 10.1002/cphc.201700896] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Indexed: 11/06/2022]
Abstract
The effect of water addition during preparation of a CH3 NH3 PbI3 layer on the photodynamics is studied by femtosecond transient absorption. Both the regular perovskite and the aqueous analogue show charge thermalisation on a timescale of about 500 fs. This process is, however, less pronounced in the latter layer. The spectral feature associated with hot charges does not fully decay on this timescale, but also shows a long-lived (sub-ns) component. As water molecules may interfere with the hydrogen bonding between the CH3 NH3+ cations and the inorganic cage, this effect is possibly caused by immobilisation of cation motion, suggesting a key role of CH3 NH3+ dipole reorientation in charge thermalisation. This effect shows the possibility of controlling hot charge carrier cooling to overcome the Shockley-Queisser limit.
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Affiliation(s)
- S Aphrham
- MESA+ Institute for Nanotechnology, University of Twente, 7500, AE, Enschede, The Netherlands
| | - Q Pan
- MESA+ Institute for Nanotechnology, University of Twente, 7500, AE, Enschede, The Netherlands.,Institute of Molecules and Materials, Radboud University Nijmegen, 6525, AJ, Nijmegen, The Netherlands
| | - S F Zaccarine
- MESA+ Institute for Nanotechnology, University of Twente, 7500, AE, Enschede, The Netherlands
| | - K M Felter
- Chemical Engineering department, Faculty of Applied Sciences, Delft University of Technology, 2600, GA, Delft, The Netherlands
| | - J Thieme
- Chemical Engineering department, Faculty of Applied Sciences, Delft University of Technology, 2600, GA, Delft, The Netherlands
| | | | - J E Ten Elshof
- MESA+ Institute for Nanotechnology, University of Twente, 7500, AE, Enschede, The Netherlands
| | - A Huijser
- MESA+ Institute for Nanotechnology, University of Twente, 7500, AE, Enschede, The Netherlands
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10
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Petrov A, Makrides C, Kotochigova S. Laser controlled charge-transfer reaction at low temperatures. J Chem Phys 2017; 146:084304. [DOI: 10.1063/1.4976972] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Alexander Petrov
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
- NRC Kurchatov Institute PNPI, Gatchina, Leningrad District 188300, Russia and Division of Quantum Mechanics, St. Petersburg State University, University Embankment 7-9, St. Petersburg 199034, Russia
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11
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Zarick HF, Boulesbaa A, Puretzky AA, Talbert EM, DeBra ZR, Soetan N, Geohegan DB, Bardhan R. Ultrafast carrier dynamics in bimetallic nanostructure-enhanced methylammonium lead bromide perovskites. NANOSCALE 2017; 9:1475-1483. [PMID: 28067394 DOI: 10.1039/c6nr08347a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this work, we examine the impact of hybrid bimetallic Au/Ag core/shell nanostructures on the carrier dynamics of methylammonium lead tribromide (MAPbBr3) mesoporous perovskite solar cells (PSCs). Plasmon-enhanced PSCs incorporated with Au/Ag nanostructures demonstrated improved light harvesting and increased power conversion efficiency by 26% relative to reference devices. Two complementary spectral techniques, transient absorption spectroscopy (TAS) and time-resolved photoluminescence (trPL), were employed to gain a mechanistic understanding of plasmonic enhancement processes. TAS revealed a decrease in the photobleach formation time, which suggests that the nanostructures improve hot carrier thermalization to an equilibrium distribution, relieving hot phonon bottleneck in MAPbBr3 perovskites. TAS also showed a decrease in carrier decay lifetimes, indicating that nanostructures enhance photoinduced carrier generation and promote efficient electron injection into TiO2 prior to bulk recombination. Furthermore, nanostructure-incorporated perovskite films demonstrated quenching in steady-state PL and decreases in trPL carrier lifetimes, providing further evidence of improved carrier injection in plasmon-enhanced mesoporous PSCs.
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Affiliation(s)
- Holly F Zarick
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA. and Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Abdelaziz Boulesbaa
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Eric M Talbert
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA. and Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Zachary R DeBra
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA. and Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Naiya Soetan
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA. and Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - David B Geohegan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Rizia Bardhan
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA. and Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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12
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Täuber D, Dobrovolsky A, Camacho R, Scheblykin IG. Exploring the Electronic Band Structure of Organometal Halide Perovskite via Photoluminescence Anisotropy of Individual Nanocrystals. NANO LETTERS 2016; 16:5087-94. [PMID: 27462927 DOI: 10.1021/acs.nanolett.6b02012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Understanding electronic processes in organometal halide perovskites, flourishing photovoltaic, and emitting materials requires unraveling the origin of their electronic transitions. Light polarization studies can provide important information regarding transition dipole moment orientations. Investigating individual methylammonium lead triiodide perovskite nanocrystals enabled us to detect the polarization of photoluminescence intensity and photoluminescence excitation, hidden in bulk samples by ensemble averaging. Polarization properties of the crystals were correlated with their photoluminescence spectra and electron microscopy images. We propose that distortion of PbI6 octahedra leads to peculiarities of the electronic band structure close to the band-edge. Namely, the lowest band transition possesses a transition dipole moment along the apical Pb-I-Pb bond resulting in polarized photoluminescence. Excitation of photoluminescence above the bandgap is unpolarized because it involves molecular orbitals delocalized both in the apical and equatorial directions of the perovskite octahedron. Trap-assisted emission at 77 K, rather surprisingly, was polarized similar to the bandgap emission.
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Affiliation(s)
- Daniela Täuber
- Chemical Physics and NanoLund, Lund University , Box 124, SE-22100, Lund, Sweden
| | | | - Rafael Camacho
- Chemical Physics and NanoLund, Lund University , Box 124, SE-22100, Lund, Sweden
| | - Ivan G Scheblykin
- Chemical Physics and NanoLund, Lund University , Box 124, SE-22100, Lund, Sweden
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13
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Yuan H, Debroye E, Caliandro G, Janssen KP, van Loon J, Kirschhock CEA, Martens JA, Hofkens J, Roeffaers MBJ. Photoluminescence Blinking of Single-Crystal Methylammonium Lead Iodide Perovskite Nanorods Induced by Surface Traps. ACS OMEGA 2016; 1:148-159. [PMID: 27617323 PMCID: PMC5013672 DOI: 10.1021/acsomega.6b00107] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 07/14/2016] [Indexed: 05/25/2023]
Abstract
Photoluminescence (PL) of organometal halide perovskite materials reflects the charge dynamics inside of the material and thus contains important information for understanding the electro-optical properties of the material. Interpretation of PL blinking of methylammonium lead iodide (MAPbI3) nanostructures observed on polycrystalline samples remains puzzling owing to their intrinsic disordered nature. Here, we report a novel method for the synthesis of high-quality single-crystal MAPbI3 nanorods and demonstrate a single-crystal study on MAPbI3 PL blinking. At low excitation power densities, two-state blinking was found on individual nanorods with dimensions of several hundred nanometers. A super-resolution localization study on the blinking of individual nanorods showed that single crystals of several hundred nanometers emit and blink as a whole, without showing changes in the localization center over the crystal. Moreover, both the blinking ON and OFF times showed power-law distributions, indicating trapping-detrapping processes. This is further supported by the PL decay times of the individual nanorods, which were found to correlate with the ON/OFF states. Furthermore, a strong environmental dependence of the nanorod PL blinking was revealed by comparing the measurements in vacuum, nitrogen, and air, implying that traps locate close to crystal surfaces. We explain our observations by proposing surface charge traps that are likely related to under-coordinated lead ions and methylammonium vacancies to result in the PL blinking observed here.
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Affiliation(s)
- Haifeng Yuan
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Elke Debroye
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Giorgio Caliandro
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Kris P.
F. Janssen
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Jordi van Loon
- Centre
for Surface Chemistry and Catalysis, KU
Leuven, Kasteelpark Arenberg
23, 3001 Heverlee, Belgium
| | | | - Johan A. Martens
- Centre
for Surface Chemistry and Catalysis, KU
Leuven, Kasteelpark Arenberg
23, 3001 Heverlee, Belgium
| | - Johan Hofkens
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
- RIES, Hokkaido
University,
N20W10, Kita-Ward, Sapporo 001-0020, Japan
| | - Maarten B. J. Roeffaers
- Centre
for Surface Chemistry and Catalysis, KU
Leuven, Kasteelpark Arenberg
23, 3001 Heverlee, Belgium
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Panigrahi S, Calmeiro T, Martins R, Nunes D, Fortunato E. Observation of Space Charge Dynamics Inside an All Oxide Based Solar Cell. ACS NANO 2016; 10:6139-6146. [PMID: 27244449 DOI: 10.1021/acsnano.6b02090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The charge transfer dynamics at interfaces are fundamental to know the mechanism of photovoltaic processes. The internal potential in solar cell devices depends on the basic processes of photovoltaic effect such as charge carrier generation, separation, transport, recombination, etc. Here we report the direct observation of the surface potential depth profile over the cross-section of the ZnO nanorods/Cu2O based solar cell for two different layer thicknesses at different wavelengths of light using Kelvin probe force microscopy. The topography and phase images across the cross-section of the solar cell are also observed, where the interfaces are well-defined on the nanoscale. The potential profiling results demonstrate that under white light illumination, the photoinduced electrons in Cu2O inject into ZnO due to the interfacial electric field, which results in the large difference in surface potential between two active layers. However, under a single wavelength illumination, the charge carrier generation, separation, and transport processes between two active layers are limited, which affect the surface potential images and corresponding potential depth profile. Because of changes in the active layer thicknesses, small variations have been observed in the charge carrier transport mechanism inside the device. These results provide the clear idea about the charge carrier distribution inside the solar cell in different conditions and show the perfect illumination condition for large carrier transport in a high performance solar cell.
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Affiliation(s)
- Shrabani Panigrahi
- Departamento de Ciência dos Materiais, CENIMAT/i3N, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa and CEMOP/Uninova , 2829-516 Caparica, Portugal
| | - Tomás Calmeiro
- Departamento de Ciência dos Materiais, CENIMAT/i3N, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa and CEMOP/Uninova , 2829-516 Caparica, Portugal
| | - Rodrigo Martins
- Departamento de Ciência dos Materiais, CENIMAT/i3N, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa and CEMOP/Uninova , 2829-516 Caparica, Portugal
| | - Daniela Nunes
- Departamento de Ciência dos Materiais, CENIMAT/i3N, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa and CEMOP/Uninova , 2829-516 Caparica, Portugal
| | - Elvira Fortunato
- Departamento de Ciência dos Materiais, CENIMAT/i3N, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa and CEMOP/Uninova , 2829-516 Caparica, Portugal
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