1
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Bennett RX, Hendrickson JR, Bergfield JP. Quantum Interference Enhancement of the Spin-Dependent Thermoelectric Response. ACS Nano 2024; 18:11876-11885. [PMID: 38651504 PMCID: PMC11080465 DOI: 10.1021/acsnano.4c01297] [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: 01/26/2024] [Revised: 04/01/2024] [Accepted: 04/05/2024] [Indexed: 04/25/2024]
Abstract
We investigate the influence of quantum interference (QI) and broken spin-symmetry on the thermoelectric response of node-possessing junctions, finding a dramatic enhancement of the spin-thermopower (Ss), figure-of-merit (ZsT), and maximum thermodynamic efficiency (ηsmax) caused by destructive QI. Using many-body and single-particle methods, we calculate the response of 1,3-benzenedithiol and cross-conjugated molecule-based junctions subject to an applied magnetic field, finding nearly universal behavior over a range of junction parameters with Ss, ZsT, and reaching peak values of 2 π / 3 ( k / e ) , 1.51, and 28% of Carnot efficiency, respectively. We also find that the quantum-enhanced spin-response is spectrally broad, and the field required to achieve peak efficiency scales with temperature. The influence of off-resonant thermal channels (e.g., phonon heat transport) on this effect is also investigated.
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Affiliation(s)
- Runa X. Bennett
- Department
of Physics, Illinois State University, Normal, Illinois 61790, United States
| | - Joshua R. Hendrickson
- Air
Force Research Laboratory, Sensors Directorate, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Justin P. Bergfield
- Department
of Physics, Illinois State University, Normal, Illinois 61790, United States
- Department
of Chemistry, Illinois State University, Normal, Illinois 61790, United States
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2
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Blankevoort N, Bastante P, Davidson RJ, Salthouse RJ, Daaoub AHS, Cea P, Solans SM, Batsanov AS, Sangtarash S, Bryce MR, Agrait N, Sadeghi H. Exploring the Impact of the HOMO-LUMO Gap on Molecular Thermoelectric Properties: A Comparative Study of Conjugated Aromatic, Quinoidal, and Donor-Acceptor Core Systems. ACS Omega 2024; 9:8471-8477. [PMID: 38405513 PMCID: PMC10882689 DOI: 10.1021/acsomega.3c09760] [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: 12/06/2023] [Revised: 01/22/2024] [Accepted: 01/29/2024] [Indexed: 02/27/2024]
Abstract
Thermoelectric materials have garnered significant interest for their potential to efficiently convert waste heat into electrical energy at room temperature without moving parts or harmful emissions. This study investigated the impact of the HOMO-LUMO (H-L) gap on the thermoelectric properties of three distinct classes of organic compounds: conjugated aromatics (isoindigos (IIGs)), quinoidal molecules (benzodipyrrolidones (BDPs)), and donor-acceptor systems (bis(pyrrol-2-yl)squaraines (BPSs)). These compounds were chosen for their structural simplicity and linear π-conjugated conductance paths, which promote high electrical conductance and minimize complications from quantum interference. Single-molecule thermoelectric measurements revealed that despite their low H-L gaps, the Seebeck coefficients of these compounds remain low. The alignment of the frontier orbitals relative to the Fermi energy was found to play a crucial role in determining the Seebeck coefficients, as exemplified by the BDP compounds. Theoretical calculations support these findings and suggest that anchor group selection could further enhance the thermoelectric behavior of these types of molecules.
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Affiliation(s)
- Nickel Blankevoort
- Device
Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, U.K.
| | - Pablo Bastante
- Departamento
de Física de la Materia Condensada C-III, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Ross J. Davidson
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
| | | | - Abdalghani H. S. Daaoub
- Device
Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, U.K.
| | - Pilar Cea
- Instituto
de Nanociencia y Materiales de Aragón (INMA), CSIC−Universidad de Zaragoza, 50009 Zaragoza, Spain
- Departamento
de Química Física, Universidad
de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio
de Microscopias Avanzadas (LMA), Universidad
de Zaragoza, 50018 Zaragoza, Spain
| | - Santiago Martin Solans
- Instituto
de Nanociencia y Materiales de Aragón (INMA), CSIC−Universidad de Zaragoza, 50009 Zaragoza, Spain
- Departamento
de Química Física, Universidad
de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio
de Microscopias Avanzadas (LMA), Universidad
de Zaragoza, 50018 Zaragoza, Spain
| | | | - Sara Sangtarash
- Device
Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, U.K.
| | - Martin R. Bryce
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
| | - Nicolas Agrait
- Departamento
de Física de la Materia Condensada C-III, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia
de Materiales “Nicolás Cabrera”, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Hatef Sadeghi
- Device
Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, U.K.
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3
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Senapati P, Parida P. Charge and spin thermoelectric transport in benzene-based molecular nano-junctions: a quantum many-body study. Nanoscale 2024; 16:2574-2590. [PMID: 38224290 DOI: 10.1039/d3nr04714h] [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] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Within the Coulomb blockade regime, our study delves into the charge, spin, and thermoelectric transport characteristics of a benzene-based molecular nano-junction using the Pauli master equation and linear response theory. The charge- and spin-transport studies show strong negative differential conductance features in the current-voltage (I-V) characteristics for the ortho and meta connections of electrodes on either side. Contrarily, the para-connection displays Coulomb staircase behavior. By exploring spin current behavior in the presence of spin-polarized electrodes or an external Zeeman field, we establish a methodology that facilitates precise control over the specific spin flow. Various charge and spin thermoelectric transport coefficients have been studied with varying chemical potentials. We focus on spin-polarized conductance, the Seebeck coefficient, and the figure of merit. By adjusting electrode polarization or employing an external magnetic field, we achieve an impressive peak value for the spin thermoelectric figure of merit, approximately 4.10. This outcome underscores the strategic value of harnessing both spin-polarized electrodes and external magnetic fields within the domain of spin caloritronics.
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Affiliation(s)
- Parbati Senapati
- Department of Physics, Indian Institute of Technology Patna, Bihta, Bihar, 801106, India.
| | - Prakash Parida
- Department of Physics, Indian Institute of Technology Patna, Bihta, Bihar, 801106, India.
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4
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Abed HH, Al-Khaykanee MK, Abduljalil HM, Abdulsattar MA. Investigation of thermoelectric properties of cadmium selenide Cd nSe n (n= 7, 11, 13) molecular junctions: a DFT study. J Mol Model 2023; 30:12. [PMID: 38102331 DOI: 10.1007/s00894-023-05805-z] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023]
Abstract
CONTEXT The thermoelectric properties of cadmium selenide (CdnSen) molecular junctions (n = 7, 11, 13) were investigated before and after adding hydrogen atoms. The effects of hydrogen passivation on the transmission and thermopower curves were analyzed. CdSe-diamantane (Cd7Se7) and CdSe-tetramantane (Cd11Se11) junctions exhibited the best thermoelectric performance due to their low surface reconstruction energy, which is attributed to the number of dangling and unsaturated bonds. This study guides the design of new molecular junctions with desired thermoelectric properties. METHOD The electrical and thermal properties of cadmium selenide (CdnSen) molecular junctions (n = 7, 11, 13) were investigated using a ballistic quantum transport method based on the non-equilibrium Green's function (NEGF) approach. Thermoelectric properties were calculated for the molecular junctions with different structures before and after hydrogen passivation. Density functional theory (DFT) calculations were performed at the B3LYP level with the 3-21G basis set for the Cd atoms and the 6-31G** basis set for the Se atoms. The SIESTA and GOLLUM codes were used to study the effect of changing the shape and size of each structure on its electrical and thermal characteristics.
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Affiliation(s)
- Hussein Hakim Abed
- Department of Physics, College of Science, University of Babylon, Hilla, Iraq.
| | | | - Hayder M Abduljalil
- Department of Physics, College of Science, University of Babylon, Hilla, Iraq
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5
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Alsaqer M, Daaoub AH, Sangtarash S, Sadeghi H. Large Mechanosensitive Thermoelectric Enhancement in Metallo-Organic Magnetic Molecules. Nano Lett 2023; 23:10719-10724. [PMID: 37988562 PMCID: PMC10722535 DOI: 10.1021/acs.nanolett.3c02569] [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: 07/10/2023] [Revised: 11/15/2023] [Accepted: 11/15/2023] [Indexed: 11/23/2023]
Abstract
Organic materials are promising candidates for thermoelectric cooling and energy harvesting at room temperature. However, their electrical conductance (G) and Seebeck coefficient (S) need to be improved to make them technologically competitive. Therefore, radically new strategies need to be developed to tune their thermoelectric properties. Here, we demonstrate that G and S can be tuned mechanically in paramagnetic metallocenes, and their thermoelectric properties can be significantly enhanced by the application of mechanical forces. With a 2% junction compression, the full thermoelectric figure of merit is enhanced by more than 200 times. We demonstrate that this is because spin transport resonances in paramagnetic metallocenes are strongly sensitive to the interaction between organic ligands and the metal center, which is not the case in their diamagnetic analogue. These results open a new avenue for the development of organic thermoelectric materials for cooling future quantum computers and generating electricity from low-grade energy sources.
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Affiliation(s)
- Munirah Alsaqer
- Device Modelling Group, School
of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - Abdalghani H.S. Daaoub
- Device Modelling Group, School
of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - Sara Sangtarash
- Device Modelling Group, School
of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - Hatef Sadeghi
- Device Modelling Group, School
of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
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6
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Abstract
Robust organic triradicals with high-spin quartet ground states provide promising applications in molecular magnets, spintronics, etc. In this context, a triradical based on Blatter's radical has been synthesized recently, having two low-lying non-degenerate doublet states with a quartet ground state. The traditional broken-symmetry (BS)-DFT computed doublet-quartet energy gaps are reported to be somewhat overestimated in comparison to the experimentally observed values. In this work, we have employed different ab initio methods on this prototypical system to obtain more accurate doublet-quartet energy gaps for this triradical. The spin-constraint broken-symmetry (CBS)-DFT method has been used to reduce the overestimation of energy gaps from BS-DFT. To address the issues of spin-contamination and the multireference nature of low-spin states affecting the DFT methods, we have computed the energy gaps using appropriately state-averaged CASSCF and NEVPT2 computations. Using a series of active spaces, our calculations are shown to provide quite accurate values in concordance with the experimentally observed results. Furthermore, we have proposed and modeled another two triradicals based on Blatter's radical, which are of interest for experimental synthesis and characterization. Our computations show that all these triradicals also have a quartet ground state with a similar energy difference between the excited doublet states.
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Affiliation(s)
- Rishu Khurana
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
| | - Ashima Bajaj
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
| | - K R Shamasundar
- Indian Institute of Science Education and Research Mohali, Sector-81, Mohali, Punjab 140306, India
| | - Md Ehesan Ali
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
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7
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Zhang W, Liu X, Jiao K, Wang Q, Yang C, Zhao C. Ion Steric Effect Induces Giant Enhancement of Thermoelectric Conversion in Electrolyte-Filled Nanochannels. Nano Lett 2023; 23:8264-8271. [PMID: 37590911 DOI: 10.1021/acs.nanolett.3c02469] [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] [Indexed: 08/19/2023]
Abstract
Ionic thermoelectricity in nanochannels has received increasing attention because of its advantages, such as high Seebeck coefficient and low cost. However, most studies have focused on dilute simple electrolytes that neglect the effects of finite ion sizes and short-range electrostatic correlation. Here, we reveal a new thermoelectric mechanism arising from the coupling of the ion steric effect due to finite ion sizes and ion thermodiffusion in electric double layers, using both theoretical and numerical methods. We show that this mechanism can significantly enhance the thermoelectric response in nanoconfined electrolytes depending on the properties of electrolytes and nanochannels. Compared to the previously known mechanisms, the new mechanism can increase the Seebeck coefficient by 100% or even 1 order of magnitude enhancement under optimal conditions. Moreover, we demonstrate that the short-range electrostatic correlation can help preserve the Seebeck coefficient enhancement in a weaker confinement or in more concentrated electrolytes.
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Affiliation(s)
- Wenyao Zhang
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xinxi Liu
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Kai Jiao
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Qiuwang Wang
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Chun Yang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Cunlu Zhao
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
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8
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Camargo B, Zajcewa I, Pietrzak A, Obijalska E, Szczytko J, Kaszyński P. Thermally induced dimensionality changes in derivatives of a "super stable" Blatter radical. Phys Chem Chem Phys 2023; 25:22813-22818. [PMID: 37584108 DOI: 10.1039/d3cp01298k] [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: 08/17/2023]
Abstract
Two derivatives of a "super stable" Blatter radical (1,3-diphenyl-7-trifluoromethyl-1,4-dihydrobenzo[e][1,2,4]triazin-4-yl) with N(1)-Ar = 2-CF3C6H4 and 2-MeOC6H4 were obtained and investigated using XRD and SQUID magnetometry methods. The investigation revealed strong antiferromagnetic interactions in both radicals, which are described using the Hatfield model. For the latter radical, an abrupt and reversible change in the χ(T) plot was observed at 29 K. It was ascribed to a structural transition, consistent with a two-dimensional to one-dimensional thermally activated crossover, as supported by specific heat measurements (CvHvs. T). It is suggested that the transition is related to an order-disorder transition of the CF3 group, which is corroborated using XRD structural analysis.
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Affiliation(s)
- Bruno Camargo
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland
| | - Irina Zajcewa
- Institute of Physics, Polish Academy of Sciences, 02668 Warsaw, Poland
| | - Anna Pietrzak
- Faculty of Chemistry, Łódź University of Technology, 90-924 Łódź, Poland
| | | | - Jacek Szczytko
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland
| | - Piotr Kaszyński
- Faculty of Chemistry, University of Łódź, 91-403 Łódź, Poland
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Łódź, Poland
- Department of Chemistry, Middle Tennessee State University, Murfreesboro, TN, 37130, USA.
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9
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Abstract
Radicals are unique molecular systems for applications in electronic devices due to their open-shell electronic structures. Radicals can function as good electrical conductors and switches in molecular circuits while also holding great promise in the field of molecular spintronics. However, it is both challenging to create stable, persistent radicals and to understand their properties in molecular junctions. The goal of this Perspective is to address this dual challenge by providing design principles for the synthesis of stable radicals relevant to molecular junctions, as well as offering current insight into the electronic properties of radicals in single-molecule devices. By exploring both the chemical and physical properties of established radical systems, we will facilitate increased exploration and development of radical-based molecular systems.
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Affiliation(s)
- Liang Li
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Claudia R Prindle
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Wanzhuo Shi
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Colin Nuckolls
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Latha Venkataraman
- Department of Chemistry, Columbia University, New York, New York 10027, United States
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
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10
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Li T, Bandari VK, Schmidt OG. Molecular Electronics: Creating and Bridging Molecular Junctions and Promoting Its Commercialization. Adv Mater 2023; 35:e2209088. [PMID: 36512432 DOI: 10.1002/adma.202209088] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/28/2022] [Indexed: 06/02/2023]
Abstract
Molecular electronics is driven by the dream of expanding Moore's law to the molecular level for next-generation electronics through incorporating individual or ensemble molecules into electronic circuits. For nearly 50 years, numerous efforts have been made to explore the intrinsic properties of molecules and develop diverse fascinating molecular electronic devices with the desired functionalities. The flourishing of molecular electronics is inseparable from the development of various elegant methodologies for creating nanogap electrodes and bridging the nanogap with molecules. This review first focuses on the techniques for making lateral and vertical nanogap electrodes by breaking, narrowing, and fixed modes, and highlights their capabilities, applications, merits, and shortcomings. After summarizing the approaches of growing single molecules or molecular layers on the electrodes, the methods of constructing a complete molecular circuit are comprehensively grouped into three categories: 1) directly bridging one-molecule-electrode component with another electrode, 2) physically bridging two-molecule-electrode components, and 3) chemically bridging two-molecule-electrode components. Finally, the current state of molecular circuit integration and commercialization is discussed and perspectives are provided, hoping to encourage the community to accelerate the realization of fully scalable molecular electronics for a new era of integrated microsystems and applications.
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Affiliation(s)
- Tianming Li
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Vineeth Kumar Bandari
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Oliver G Schmidt
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
- Nanophysics, Dresden University of Technology, 01069, Dresden, Germany
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11
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Chelli Y, Sandhu S, Daaoub AHS, Sangtarash S, Sadeghi H. Controlling Spin Interference in Single Radical Molecules. Nano Lett 2023; 23:3748-3753. [PMID: 37071608 PMCID: PMC10176569 DOI: 10.1021/acs.nanolett.2c05068] [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: 12/27/2022] [Revised: 04/13/2023] [Indexed: 05/11/2023]
Abstract
Quantum interference (QI) dominates the electronic properties of single molecules even at room temperature and can lead to a large change in their electrical conductance. To take advantage of this for nanoelectronic applications, a mechanism to electronically control QI in single molecules needs to be developed. In this paper, we demonstrate that controlling the quantum interference of each spin in a stable open-shell organic radical with a large π-system is possible by changing the spin state of the radical. We show that the counterintuitive constructive spin interference in a meta-connected radical changes to destructive interference by changing the spin state of the radical from a doublet to a singlet. This results in a significant change in the room temperature electrical conductance by several orders of magnitude, opening up new possibilities for spin interference based molecular switches for energy storage and conversion applications.
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Affiliation(s)
- Yahia Chelli
- Device Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Serena Sandhu
- Device Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Abdalghani H. S. Daaoub
- Device Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Sara Sangtarash
- Device Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Hatef Sadeghi
- Device Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
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12
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Nicolaides C, Bazzi F, Vouros E, Flesariu DF, Chrysochos N, Koutentis PA, Constantinides CP, Trypiniotis T. Metal-Free Organic Radical Spin Source. Nano Lett 2023; 23:4579-4586. [PMID: 37154760 DOI: 10.1021/acs.nanolett.3c01044] [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] [Indexed: 05/10/2023]
Abstract
Organic radicals have long been suggested as candidates for organic magnets and components in organic spintronic devices. Herein, we demonstrate spin current emission from an organic radical film via spin pumping at room temperature. We present the synthesis and the thin film preparation of a Blatter-type radical with outstanding stability and low roughness. These features enable the fabrication of a radical/ferromagnet bilayer, in which the spin current emission from the organic radical layer can be reversibly reduced when the ferromagnetic film is brought into simultaneous resonance with the radical. The results provide an experimental demonstration of a metal-free organic radical layer operating as a spin source, opening a new avenue for the development of purely organic spintronic devices and bridging the gap between potential and real applications.
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Affiliation(s)
| | - Fadwat Bazzi
- Department of Natural Sciences, University of Michigan - Dearborn, 4901 Evergreen Rd, Dearborn, Michigan 48128-1491, United States
| | - Evangelos Vouros
- Department of Physics, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Dragos F Flesariu
- Department of Chemistry, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Nicolas Chrysochos
- Department of Chemistry, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
| | | | - Christos P Constantinides
- Department of Natural Sciences, University of Michigan - Dearborn, 4901 Evergreen Rd, Dearborn, Michigan 48128-1491, United States
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13
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Yang X, Hou S, Su M, Zhan Q, Zhang H, Quintero SM, Liu X, Liu J, Hong W, Casado J, Wu Q, Lambert CJ, Zheng Y. Quasi-Free Electron States Responsible for Single-Molecule Conductance Enhancement in Stable Radical. J Phys Chem Lett 2023; 14:4004-4010. [PMID: 37083476 DOI: 10.1021/acs.jpclett.3c00536] [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: 05/03/2023]
Abstract
Stable organic radicals, which possess half-filled orbitals in the vicinity of the Fermi energy, are promising candidates for electronic devices. In this Letter, using a combination of scanning-tunneling-microscopy-based break junction (STM-BJ) experiments and quantum transport theory, a stable fluorene-based radical is investigated. We demonstrate that the transport properties of a series of fluorene derivatives can be tuned by controlling the degree of localization of certain orbitals. More specifically, radical 36-FR has a delocalized half-filled orbital resulting in Breit-Wigner resonances, leading to an unprecedented conductance enhancement of 2 orders of magnitude larger than the neutral nonradical counterpart (36-FOH). In other words, conversion from a closed-shell fluorene derivative to the free radical in 36-FR opens an electron transport path which massively enhances the conductance. This new understanding of the role of radicals in single-molecule junctions opens up a novel design strategy for single-molecule-based spintronic devices.
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Affiliation(s)
- Xingzhou Yang
- Department of Pharmacy, Sichuan Provincial People's Hospital, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610072, People's Republic of China
| | - Songjun Hou
- Department of Physics, Lancaster University, Lancaster LA1 4YB, U.K
| | - Meiling Su
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xia-men University, Xiamen 361005, People's Republic of China
| | - Qian Zhan
- Department of Pharmacy, Sichuan Provincial People's Hospital, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610072, People's Republic of China
| | - Hanjun Zhang
- Department of Pharmacy, Sichuan Provincial People's Hospital, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610072, People's Republic of China
| | - Sergio M Quintero
- Department of Physical Chemistry, University of Málaga, Andalucia-Tech Campus de Teatinos s/n, Málaga 29071, Spain
| | - Xiaodong Liu
- Department of Pharmacy, Sichuan Provincial People's Hospital, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610072, People's Republic of China
| | - Junyang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xia-men University, Xiamen 361005, People's Republic of China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xia-men University, Xiamen 361005, People's Republic of China
| | - Juan Casado
- Department of Physical Chemistry, University of Málaga, Andalucia-Tech Campus de Teatinos s/n, Málaga 29071, Spain
| | - Qingqing Wu
- Department of Physics, Lancaster University, Lancaster LA1 4YB, U.K
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster LA1 4YB, U.K
| | - Yonghao Zheng
- Department of Pharmacy, Sichuan Provincial People's Hospital, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610072, People's Republic of China
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Obijalska E, Pietrzak A, Constantinides CP, Sommer RD, Kaszyński P. "Super stable" Blatter radicals through ArLi addition: surprising chemistry of 7-(trifluoromethyl)benzo[ e][1,2,4]triazine. Chem Commun (Camb) 2023; 59:4008-4011. [PMID: 36916722 DOI: 10.1039/d3cc00832k] [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: 03/09/2023]
Abstract
Addition of PhLi to 7-(CF3)benzo[e][1,2,4]triazine at -78 °C gives the "super stable" Blatter radical in high yields, while above -5 °C two additional products are formed. XRD analysis revealed the formation of a "trimer" and a benzo[f][1,2,4]triazepine via a novel mechanism. The latter is formed from the anion generated from the isolated radical, which suggests its instability in organic batteries.
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Affiliation(s)
- Emilia Obijalska
- Faculty of Chemistry, University of Łódź, Tamka 12, 91-403 Łódź, Poland.
| | - Anna Pietrzak
- Faculty of Chemistry, Łódź University of Technology, Żeromskiego 116, 90-924 Łódź, Poland
| | | | - Roger D Sommer
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Piotr Kaszyński
- Faculty of Chemistry, University of Łódź, Tamka 12, 91-403 Łódź, Poland. .,Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Łódź, Poland.,Department of Chemistry, Middle Tennessee State University, Murfreesboro, TN 37130, USA
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15
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Naghibi S, Sangtarash S, Kumar VJ, Wu J, Judd MM, Qiao X, Gorenskaia E, Higgins SJ, Cox N, Nichols RJ, Sadeghi H, Low PJ, Vezzoli A. Redox-Addressable Single-Molecule Junctions Incorporating a Persistent Organic Radical. Angew Chem Int Ed Engl 2022; 61:e202116985. [PMID: 35289977 PMCID: PMC9322687 DOI: 10.1002/anie.202116985] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [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: 12/13/2021] [Indexed: 12/14/2022]
Abstract
Integrating radical (open-shell) species into non-cryogenic nanodevices is key to unlocking the potential of molecular electronics. While many efforts have been devoted to this issue, in the absence of a chemical/electrochemical potential the open-shell character is generally lost in contact with the metallic electrodes. Herein, single-molecule devices incorporating a 6-oxo-verdazyl persistent radical have been fabricated using break-junction techniques. The open-shell character is retained at room temperature, and electrochemical gating permits in situ reduction to a closed-shell anionic state in a single-molecule transistor configuration. Furthermore, electronically driven rectification arises from bias-dependent alignment of the open-shell resonances. The integration of radical character, transistor-like switching, and rectification in a single molecular component paves the way to further studies of the electronic, magnetic, and thermoelectric properties of open-shell species.
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Affiliation(s)
- Saman Naghibi
- Department of ChemistryUniversity of LiverpoolCrown StreetLiverpoolL69 7ZDUK
| | | | - Varshini J. Kumar
- School of Molecular SciencesUniversity of Western AustraliaCrawleyWestern Australia6009Australia
| | - Jian‐Zhong Wu
- School of ChemistrySouth China Normal UniversityGuangzhou510006P.R. China
| | - Martyna M. Judd
- Research School of ChemistryAustralian National UniversityCanberraATC 2601Australia
| | - Xiaohang Qiao
- Department of ChemistryUniversity of LiverpoolCrown StreetLiverpoolL69 7ZDUK
| | - Elena Gorenskaia
- School of Molecular SciencesUniversity of Western AustraliaCrawleyWestern Australia6009Australia
| | - Simon J. Higgins
- Department of ChemistryUniversity of LiverpoolCrown StreetLiverpoolL69 7ZDUK
| | - Nicholas Cox
- Research School of ChemistryAustralian National UniversityCanberraATC 2601Australia
| | - Richard J. Nichols
- Department of ChemistryUniversity of LiverpoolCrown StreetLiverpoolL69 7ZDUK
| | - Hatef Sadeghi
- School of EngineeringUniversity of WarwickCoventryCV4 7ALUK
| | - Paul J. Low
- School of Molecular SciencesUniversity of Western AustraliaCrawleyWestern Australia6009Australia
| | - Andrea Vezzoli
- Department of ChemistryUniversity of LiverpoolCrown StreetLiverpoolL69 7ZDUK
- Stephenson Institute for Renewable EnergyUniversity of LiverpoolPeach StreetLiverpoolL69 7ZFUK
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16
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Naghibi S, Sangtarash S, Kumar VJ, Wu J, Judd MM, Qiao X, Gorenskaia E, Higgins SJ, Cox N, Nichols RJ, Sadeghi H, Low PJ, Vezzoli A. Redox‐Addressable Single‐Molecule Junctions Incorporating a Persistent Organic Radical**. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202116985] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Saman Naghibi
- Department of Chemistry University of Liverpool Crown Street Liverpool L69 7ZD UK
| | - Sara Sangtarash
- School of Engineering University of Warwick Coventry CV4 7AL UK
| | - Varshini J. Kumar
- School of Molecular Sciences University of Western Australia Crawley Western Australia 6009 Australia
| | - Jian‐Zhong Wu
- School of Chemistry South China Normal University Guangzhou 510006 P.R. China
| | - Martyna M. Judd
- Research School of Chemistry Australian National University Canberra ATC 2601 Australia
| | - Xiaohang Qiao
- Department of Chemistry University of Liverpool Crown Street Liverpool L69 7ZD UK
| | - Elena Gorenskaia
- School of Molecular Sciences University of Western Australia Crawley Western Australia 6009 Australia
| | - Simon J. Higgins
- Department of Chemistry University of Liverpool Crown Street Liverpool L69 7ZD UK
| | - Nicholas Cox
- Research School of Chemistry Australian National University Canberra ATC 2601 Australia
| | - Richard J. Nichols
- Department of Chemistry University of Liverpool Crown Street Liverpool L69 7ZD UK
| | - Hatef Sadeghi
- School of Engineering University of Warwick Coventry CV4 7AL UK
| | - Paul J. Low
- School of Molecular Sciences University of Western Australia Crawley Western Australia 6009 Australia
| | - Andrea Vezzoli
- Department of Chemistry University of Liverpool Crown Street Liverpool L69 7ZD UK
- Stephenson Institute for Renewable Energy University of Liverpool Peach Street Liverpool L69 7ZF UK
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