1
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Algharagholy LA, García-Suárez VM, Bardan KH. Robust nanotube-based nanosensor designed for the detection of explosive molecules. NANOSCALE ADVANCES 2024; 6:3553-3565. [PMID: 38989522 PMCID: PMC11232540 DOI: 10.1039/d4na00166d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/29/2024] [Indexed: 07/12/2024]
Abstract
The adequate determination and detection of explosive molecules is key to introducing improvements in areas related to safety, whose progress depends on an adequate and rapid determination of dangerous substances. To detect explosives down to the molecular level and accurately discriminate between different but somehow similar substances, it is necessary to design sensors that can differentiate them uniquely and efficiently. In this study, we present a new generation nanoscale sensor based on carbon nanotubes with an adapted nanopore shape that is capable of effectively discriminating between five types of explosive compounds (TATP, RDX, PENT, HMX and DNT). We show that the interaction of each compound with the walls of the nanotubes induces changes in transmission and current that allows clear differentiation of each type of molecule. Interestingly, the transport properties do not depend on the orientation of the molecules within the nanopore in most cases, making it a robust device with high reproducibility and stability. The results also show that these systems can lead to relatively high thermoelectric performances and, furthermore, the Seebeck coefficient can be used to discriminate between them.
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Affiliation(s)
- Laith A Algharagholy
- Department of Physics, College of Science, University of Sumer Al Rifaee Zip: 64005 Thi-Qar Iraq
| | | | - Kareem Hasan Bardan
- Department of Physics, College of Science, University of Sumer Al Rifaee Zip: 64005 Thi-Qar Iraq
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2
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Al-Owaedi OA. Thermoelectric Properties of Porphyrin Nano Rings: A Theoretical and Modelling Investigation. Chemphyschem 2024; 25:e202300616. [PMID: 38084460 DOI: 10.1002/cphc.202300616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/01/2023] [Indexed: 03/02/2024]
Abstract
Propagation of De Broglie waves through nanomolecular junctions is greatly affected by molecular topology changes, which in turn plays a key role in determining the electronic and thermoelectric properties of source|molecule|drain junctions. The probing and realization of the constructive quantum interference (CQI) and a destructive quantum interference (DQI) are well established in this work. The critical role of quantum interference (QI) in governing and enhancing the transmission coefficient T(E), thermopower (S), power factor (P) and electronic figure of merit (ZelT) of porphyrin nanorings has been investigated using a combination of density functional theory (DFT) methods, a tight binding (Hückel) modelling (TBHM) and quantum transport theory (QTT). Remarkably, DQI not only dominates the asymmetric molecular pathways and lowering T(E), but also improves the thermoelectric properties.
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Affiliation(s)
- Oday A Al-Owaedi
- Department of Laser Physics, University of Babylon, Babylon, Hilla, 51001, Iraq
- Al-Zahrawi University College, Holy Karbala, Karbala, 56001, Iraq
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3
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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] [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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4
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Wang X, Lamantia A, Jay M, Sadeghi H, Lambert CJ, Kolosov OV, Robinson BJ. Determination of electric and thermoelectric properties of molecular junctions by AFM in peak force tapping mode. NANOTECHNOLOGY 2023; 34:385704. [PMID: 37336192 DOI: 10.1088/1361-6528/acdf67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/19/2023] [Indexed: 06/21/2023]
Abstract
Molecular thin films, such as self-assembled monolayers (SAMs), offer the possibility of translating the optimised thermophysical and electrical properties of high-Seebeck-coefficient single molecules to scalable device architectures. However, for many scanning probe-based approaches attempting to characterise such SAMs, there remains a significant challenge in recovering single-molecule equivalent values from large-area films due to the intrinsic uncertainty of the probe-sample contact area coupled with film damage caused by contact forces. Here we report a new reproducible non-destructive method for probing the electrical and thermoelectric (TE) properties of small assemblies (10-103) of thiol-terminated molecules arranged within a SAM on a gold surface, and demonstrate the successful and reproducible measurements of the equivalent single-molecule electrical conductivity and Seebeck values. We have used a modified thermal-electric force microscopy approach, which integrates the conductive-probe atomic force microscope, a sample positioned on a temperature-controlled heater, and a probe-sample peak-force feedback that interactively limits the normal force across the molecular junctions. The experimental results are interpreted by density functional theory calculations allowing quantification the electrical quantum transport properties of both single molecules and small clusters of molecules. Significantly, this approach effectively eliminates lateral forces between probe and sample, minimising disruption to the SAM while enabling simultaneous mapping of the SAMs nanomechanical properties, as well as electrical and/or TE response, thereby allowing correlation of the film properties.
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Affiliation(s)
- Xintai Wang
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
- School of Information Science and Technology, Dalian Maritime University, Dalian, 116026, People's Republic of China
| | - Angelo Lamantia
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
| | - Michael Jay
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
| | - Hatef Sadeghi
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
| | - Oleg V Kolosov
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
| | - Benjamin J Robinson
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
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5
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Svatek S, Sacchetti V, Rodríguez-Pérez L, Illescas BM, Rincón-García L, Rubio-Bollinger G, González MT, Bailey S, Lambert CJ, Martín N, Agraït N. Enhanced Thermoelectricity in Metal-[60]Fullerene-Graphene Molecular Junctions. NANO LETTERS 2023; 23:2726-2732. [PMID: 36970777 PMCID: PMC10103166 DOI: 10.1021/acs.nanolett.3c00014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 03/14/2023] [Indexed: 06/18/2023]
Abstract
The thermoelectric properties of molecular junctions consisting of a metal Pt electrode contacting [60]fullerene derivatives covalently bound to a graphene electrode have been studied by using a conducting-probe atomic force microscope (c-AFM). The [60]fullerene derivatives are covalently linked to the graphene via two meta-connected phenyl rings, two para-connected phenyl rings, or a single phenyl ring. We find that the magnitude of the Seebeck coefficient is up to nine times larger than that of Au-C60-Pt molecular junctions. Moreover, the sign of the thermopower can be either positive or negative depending on the details of the binding geometry and on the local value of the Fermi energy. Our results demonstrate the potential of using graphene electrodes for controlling and enhancing the thermoelectric properties of molecular junctions and confirm the outstanding performance of [60]fullerene derivatives.
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Affiliation(s)
- Simon
A. Svatek
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
- Departamento
de Física de la Materia Condensada, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente
7, 28049 Madrid, Spain
| | - Valentina Sacchetti
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
- Organic
Chemistry Department, Faculty of Chemistry, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Laura Rodríguez-Pérez
- Organic
Chemistry Department, Faculty of Chemistry, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Beatriz M. Illescas
- Organic
Chemistry Department, Faculty of Chemistry, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Laura Rincón-García
- Departamento
de Física de la Materia Condensada, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente
7, 28049 Madrid, Spain
| | - Gabino Rubio-Bollinger
- Departamento
de Física de la Materia Condensada, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente
7, 28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia
de Materiales “Nicolás Cabrera” (INC), Facultad
de Ciencias, Universidad Autónoma
de Madrid, C/Francisco
Tomás y Valiente 7, 28049 Madrid, Spain
| | - M. Teresa González
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
| | - Steven Bailey
- Department
of Physics, Lancaster University, Lancaster LA1 4YW, United Kingdom
| | - Colin J. Lambert
- Department
of Physics, Lancaster University, Lancaster LA1 4YW, United Kingdom
| | - Nazario Martín
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
- Organic
Chemistry Department, Faculty of Chemistry, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Nicolás Agraït
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
- Departamento
de Física de la Materia Condensada, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente
7, 28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia
de Materiales “Nicolás Cabrera” (INC), Facultad
de Ciencias, Universidad Autónoma
de Madrid, C/Francisco
Tomás y Valiente 7, 28049 Madrid, Spain
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6
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Hurtado-Gallego J, Sangtarash S, Davidson R, Rincón-García L, Daaoub A, Rubio-Bollinger G, Lambert CJ, Oganesyan VS, Bryce MR, Agraït N, Sadeghi H. Thermoelectric Enhancement in Single Organic Radical Molecules. NANO LETTERS 2022; 22:948-953. [PMID: 35073099 DOI: 10.1021/acs.nanolett.1c03698] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Organic thermoelectric materials have potential for wearable heating, cooling, and energy generation devices at room temperature. For this to be technologically viable, high-conductance (G) and high-Seebeck-coefficient (S) materials are needed. For most semiconductors, the increase in S is accompanied by a decrease in G. Here, using a combined experimental and theoretical investigation, we demonstrate that a simultaneous enhancement of S and G can be achieved in single organic radical molecules, thanks to their intrinsic spin state. A counterintuitive quantum interference (QI) effect is also observed in stable Blatter radical molecules, where constructive QI occurs for a meta-connected radical, leading to further enhancement of thermoelectric properties. Compared to an analogous closed-shell molecule, the power factor is enhanced by more than 1 order of magnitude in radicals. These results open a new avenue for the development of organic thermoelectric materials operating at room temperature.
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Affiliation(s)
- Juan Hurtado-Gallego
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Sara Sangtarash
- Device Modelling Group, School of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - Ross Davidson
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Laura Rincón-García
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Abdalghani Daaoub
- Device Modelling Group, School of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitatio de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Colin J Lambert
- Physics Department, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Vasily S Oganesyan
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Martin R Bryce
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitatio de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
| | - Hatef Sadeghi
- Device Modelling Group, School of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
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7
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Wang X, Ismael A, Almutlg A, Alshammari M, Al-Jobory A, Alshehab A, Bennett TLR, Wilkinson LA, Cohen LF, Long NJ, Robinson BJ, Lambert C. Optimised power harvesting by controlling the pressure applied to molecular junctions. Chem Sci 2021; 12:5230-5235. [PMID: 34163759 PMCID: PMC8179551 DOI: 10.1039/d1sc00672j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 02/22/2021] [Indexed: 11/21/2022] Open
Abstract
A major potential advantage of creating thermoelectric devices using self-assembled molecular layers is their mechanical flexibility. Previous reports have discussed the advantage of this flexibility from the perspective of facile skin attachment and the ability to avoid mechanical deformation. In this work, we demonstrate that the thermoelectric properties of such molecular devices can be controlled by taking advantage of their mechanical flexibility. The thermoelectric properties of self-assembled monolayers (SAMs) fabricated from thiol terminated molecules were measured with a modified AFM system, and the conformation of the SAMs was controlled by regulating the loading force between the organic thin film and the probe, which changes the tilt angle at the metal-molecule interface. We tracked the thermopower shift vs. the tilt angle of the SAM and showed that changes in both the electrical conductivity and Seebeck coefficient combine to optimize the power factor at a specific angle. This optimization of thermoelectric performance via applied pressure is confirmed through the use of theoretical calculations and is expected to be a general method for optimising the power factor of SAMs.
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Affiliation(s)
- Xintai Wang
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- The Blackett Laboratory, Imperial College London, South Kensington Campus London SW7 2AZ UK
| | - Ali Ismael
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Education for Pure Science, Tikrit University Tikrit Iraq
| | - Ahmad Almutlg
- Physics Department, Lancaster University Lancaster LA1 4YB UK
| | | | - Alaa Al-Jobory
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Science, University of Anbar Anbar Iraq
| | | | - Troy L R Bennett
- Department of Chemistry, Imperial College London, MSRH White City London W12 0BZ UK
| | - Luke A Wilkinson
- Department of Chemistry, Imperial College London, MSRH White City London W12 0BZ UK
- Department of Chemistry, University of York Heslington York YO10 5DD UK
| | - Lesley F Cohen
- The Blackett Laboratory, Imperial College London, South Kensington Campus London SW7 2AZ UK
| | - Nicholas J Long
- Department of Chemistry, Imperial College London, MSRH White City London W12 0BZ UK
| | | | - Colin Lambert
- Physics Department, Lancaster University Lancaster LA1 4YB UK
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8
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The Effect of Anchor Group on the Phonon Thermal Conductance of Single Molecule Junctions. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11031066] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
There is a worldwide race to convert waste heat to useful energy using thermoelectric materials. Molecules are attractive candidates for thermoelectricity because they can be synthesised with the atomic precision, and intriguing properties due to quantum effects such as quantum interference can be induced at room temperature. Molecules are also expected to show a low thermal conductance that is needed to enhance the performance of thermoelectric materials. Recently, the technological challenge of measuring the thermal conductance of single molecules was overcome. Therefore, it is timely to develop strategies to reduce their thermal conductance for high performance thermoelectricity. In this paper and for the first time, we exploit systematically the effect of anchor groups on the phonon thermal conductance of oligo (phenylene ethynylene) (OPE3) molecules connected to gold electrodes via pyridyl, thiol, methyl sulphide and carbodithioate anchor groups. We show that thermal conductance is affected significantly by the choice of anchor group. The lowest and highest thermal conductances were obtained in the OPE3 with methyl sulphide and carbodithioate anchor groups, respectively. The thermal conductance of OPE3 with thiol anchor was higher than that with methyl sulphide but lower than the OPE3 with pyridyl anchor group.
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9
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Dekkiche H, Gemma A, Tabatabaei F, Batsanov AS, Niehaus T, Gotsmann B, Bryce MR. Electronic conductance and thermopower of single-molecule junctions of oligo(phenyleneethynylene) derivatives. NANOSCALE 2020; 12:18908-18917. [PMID: 32902546 DOI: 10.1039/d0nr04413j] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report the synthesis and the single-molecule transport properties of three new oligo(phenyleneethynylene) (OPE3) derivatives possessing terminal dihydrobenzo[b]thiophene (DHBT) anchoring groups and various core substituents (phenylene, 2,5-dimethoxyphenylene and 9,10-anthracenyl). Their electronic conductance and their Seebeck coefficient have been determined using scanning tunneling microscopy-based break junction (STM-BJ) experiments between gold electrodes. The transport properties of the molecular junctions have been modelled using DFT-based computational methods which reveal a specific binding of the sulfur atom of the DHBT anchor to the electrodes. The experimentally determined Seebeck coefficient varies between -7.9 and -11.4 μV K-1 in the series and the negative sign is consistent with charge transport through the LUMO levels of the molecules.
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Affiliation(s)
- Hervé Dekkiche
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK.
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10
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Chen H, Sangtarash S, Li G, Gantenbein M, Cao W, Alqorashi A, Liu J, Zhang C, Zhang Y, Chen L, Chen Y, Olsen G, Sadeghi H, Bryce MR, Lambert CJ, Hong W. Exploring the thermoelectric properties of oligo(phenylene-ethynylene) derivatives. NANOSCALE 2020; 12:15150-15156. [PMID: 32658229 DOI: 10.1039/d0nr03303k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Seebeck coefficient measurements provide unique insights into the electronic structure of single-molecule junctions, which underpins their charge and heat transport properties. Since the Seebeck coefficient depends on the slope of the transmission function at the Fermi energy (EF), the sign of the thermoelectric voltage will be determined by the location of the molecular orbital levels relative to EF. Here we investigate thermoelectricity in molecular junctions formed from a series of oligophenylene-ethynylene (OPE) derivatives with biphenylene, naphthalene and anthracene cores and pyridyl or methylthio end-groups. Single-molecule conductance and thermoelectric voltage data were obtained using a home-built scanning tunneling microscope break junction technique. The results show that all the OPE derivatives studied here are dominated by the lowest unoccupied molecular orbital level. The Seebeck coefficients for these molecules follow the same trend as the energy derivatives of their corresponding transmission spectra around the Fermi level. The molecule terminated with pyridyl units has the largest Seebeck coefficient corresponding to the highest slope of the transmission function at EF. Density-functional-theory-based quantum transport calculations support the experimental results.
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Affiliation(s)
- Hang Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University, 361005, Xiamen, China.
| | - Sara Sangtarash
- Department of Physics, Lancaster University, LA1 4YB, Lancaster, UK. and School of Engineering, University of Warwick, Coventry CV4 7AL, UK
| | - Guopeng Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University, 361005, Xiamen, China.
| | | | - Wenqiang Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University, 361005, Xiamen, China.
| | - Afaf Alqorashi
- Department of Physics, Lancaster University, LA1 4YB, Lancaster, UK.
| | - Junyang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University, 361005, Xiamen, China.
| | - Chunquan Zhang
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Yulong Zhang
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen, 361005, China
| | - Lijue Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University, 361005, Xiamen, China.
| | - Yaorong Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University, 361005, Xiamen, China.
| | - Gunnar Olsen
- Department of Chemistry, Durham University, DH1 3LE, Durham, UK.
| | - Hatef Sadeghi
- School of Engineering, University of Warwick, Coventry CV4 7AL, UK
| | - Martin R Bryce
- Department of Chemistry, Durham University, DH1 3LE, Durham, UK.
| | - Colin J Lambert
- Department of Physics, Lancaster University, LA1 4YB, Lancaster, UK.
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University, 361005, Xiamen, China.
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11
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Ismael AK, Lambert CJ. Molecular-scale thermoelectricity: a worst-case scenario. NANOSCALE HORIZONS 2020; 5:1073-1080. [PMID: 32432630 DOI: 10.1039/d0nh00164c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This article highlights a novel strategy for designing molecules with high thermoelectric performance, which are resilient to fluctuations. In laboratory measurements of thermoelectric properties of single-molecule junctions and self-assembled monolayers, fluctuations in frontier orbital energies relative to the Fermi energy EF of electrodes are an important factor, which determine average values of transport coefficients, such as the average Seebeck coefficient 〈S〉. In a worst-case scenario, where the relative value of EF fluctuates uniformly over the HOMO-LUMO gap, a "worst-case scenario theorem" tells us that the average Seebeck coefficient will vanish unless the transmission coefficient at the LUMO and HOMO resonances take different values. This implies that junction asymmetry is a necessary condition for obtaining non-zero values of 〈S〉 in the presence of large fluctuations. This conclusion that asymmetry can drive high thermoelectric performance is supported by detailed simulations on 17 molecules using density functional theory. Importantly, junction asymmetry does not imply that the molecules themselves should be asymmetric. We demonstrate that symmetric molecules possessing a localised frontier orbital can achieve even higher thermoelectric performance than asymmetric molecules, because under laboratory conditions of slight symmetry breaking, such orbitals are 'silent' and do not contribute to transport. Consequently, transport is biased towards the nearest "non-silent" frontier orbital and leads to a high ensemble averaged Seebeck coefficient. This effect is demonstrated for a spatially-symmetric 1,2,3-triazole-based molecule, a rotaxane-hexayne macrocycle and a phthalocyanine.
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Affiliation(s)
- Ali K Ismael
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK.
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12
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Sun Z, Li J, Wong W. Emerging Organic Thermoelectric Applications from Conducting Metallopolymers. MACROMOL CHEM PHYS 2020. [DOI: 10.1002/macp.202000115] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zelin Sun
- The Hong Kong Polytechnic UniversityShenzhen Research Institute Shenzhen 518057 P. R. China
| | - Jiahua Li
- Department of Applied Biology and Chemical TechnologyThe Hong Kong Polytechnic University Hung Hom Hong Kong P. R. China
| | - Wai‐Yeung Wong
- The Hong Kong Polytechnic UniversityShenzhen Research Institute Shenzhen 518057 P. R. China
- Department of Applied Biology and Chemical TechnologyThe Hong Kong Polytechnic University Hung Hom Hong Kong P. R. China
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13
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Wu Q, Sadeghi H, Lambert CJ. MoS 2 nano flakes with self-adaptive contacts for efficient thermoelectric energy harvesting. NANOSCALE 2018; 10:7575-7580. [PMID: 29637971 DOI: 10.1039/c8nr01635f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We examine the potential of the low-dimensional material MoS2 for the efficient conversion of waste heat to electricity via the Seebeck effect. Recently monolayer MoS2 nano flakes with self-adaptive Mo6S6 contacts were formed, which take advantage of mechanical stability and chemical covalent bonding to the MoS2. Here, we study the thermoelectric properties of these junctions by calculating their conductance, thermopower and thermal conductance due to both electrons and phonons. We show that thermoelectric figures of merit ZT as high as ∼2.8 are accessible in these junctions, independent of the flake size and shape, provided the Fermi energy is close to a band edge. We show that Nb dopants as substituents for Mo atoms can be used to tune the Fermi energy, and despite the associated inhomogeneous broadening, room temperature values as high as ZT ∼ 0.6 are accessible, increasing to 0.8 at 500 K.
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Affiliation(s)
- Qingqing Wu
- Quantum Technology Centre, Physics Department, Lancaster University, LA1 4YB Lancaster, UK.
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Al-Galiby QH, Sadeghi H, Manrique DZ, Lambert CJ. Tuning the Seebeck coefficient of naphthalenediimide by electrochemical gating and doping. NANOSCALE 2017; 9:4819-4825. [PMID: 28352900 DOI: 10.1039/c7nr00571g] [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
We investigate the sign and magnitude of the single-molecule Seebeck coefficient of naphthalenediimide (NDI) under the influence of electrochemical gating and doping. The molecule consists of a NDI core with two alkyl chains in the bay-area position, connected to gold electrodes via benzothiophene (DBT) anchor groups. By switching between the neutral, radical and di-anion charge states, we are able to tune the molecular energy levels relative to the Fermi energy of the electrodes. The resulting single-molecule room-temperature Seebeck coefficents of the three charge states are -294.5 μV K-1, 122 μV K-1 and 144 μV K-1 respectively and the room-temperature power factors are 4.4 × 10-5 W m-1 K-2, 3 × 10-5 W m-1 K-2 and 8.2 × 10-4 W m-1 K-2. As a further strategy for optimising thermoelectric properties, we also investigate the effect on both phonon and electron transport of doping the NDI with either an electron donor (TTF) or an electron acceptor (TCNE). We find that doping by TTF increases the room-temperature Seebeck coefficient and power factor from -73.7 μV K-1 and 2.6 × 10-7 W m-1 K-2 for bare NDI to -105 μV K-1 and 3.6 × 10-4 W m-1 K-2 in presence of TTF. The low thermal conductance of NDI-TTF, combined with the higher Seebeck coefficient and higher electrical conductance lead to a maximum thermoelectric figure of merit of ZT = 1.2, which is higher than that of bare NDI in several orders of magnitude. This demonstrates that both the sign and magnitude of NDI Seebeck coefficient can be tuned reversibly by electrochemical gating and doping, suggesting that such redox active molecules are attractive materials for ultra-thin-film thermoelectric devices.
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Affiliation(s)
- Qusiy H Al-Galiby
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK. and Department of Physics, College of Education, University of Al-Qadisiyah, 58002 Iraq
| | - Hatef Sadeghi
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK.
| | - David Zsolt Manrique
- Department of Electronic & Electrical Engineering - Photonics Group, University College London, UK
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK.
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Famili M, Grace I, Sadeghi H, Lambert CJ. Suppression of Phonon Transport in Molecular Christmas Trees. Chemphyschem 2017; 18:1234-1241. [DOI: 10.1002/cphc.201700147] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Marjan Famili
- Physics Department; Lancaster University; Lancaster LA1 4YB UK
| | - Iain Grace
- Physics Department; Lancaster University; Lancaster LA1 4YB UK
| | - Hatef Sadeghi
- Physics Department; Lancaster University; Lancaster LA1 4YB UK
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Cui L, Miao R, Jiang C, Meyhofer E, Reddy P. Perspective: Thermal and thermoelectric transport in molecular junctions. J Chem Phys 2017. [DOI: 10.1063/1.4976982] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Longji Cui
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Ruijiao Miao
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chang Jiang
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Edgar Meyhofer
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Pramod Reddy
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Materials Science and Engineering,
University of Michigan, Ann Arbor, Michigan 48109,
USA
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Ismael AK, Grace I, Lambert CJ. Connectivity dependence of Fano resonances in single molecules. Phys Chem Chem Phys 2017; 19:6416-6421. [DOI: 10.1039/c7cp00126f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Using a first principles approach combined with analysis of heuristic tight-binding models, we examine the connectivity dependence of two forms of quantum interference in single molecules.
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Affiliation(s)
- Ali K. Ismael
- Department of Physics
- Lancaster University
- Lancaster
- UK
- Department of Physics
| | - Iain Grace
- Department of Physics
- Lancaster University
- Lancaster
- UK
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Almutlaq N, Al-Galiby Q, Bailey S, Lambert CJ. Identification of a positive-Seebeck-coefficient exohedral fullerene. NANOSCALE 2016; 8:13597-13602. [PMID: 27357101 DOI: 10.1039/c6nr02291j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
If fullerene-based thermoelectricity is to become a viable technology, then fullerenes exhibiting both positive and negative Seebeck coefficients are needed. C60 is known to have a negative Seebeck coefficient and therefore in this paper we address the challenge of identifying a positive-Seebeck-coefficient fullerene. We investigated the thermoelectric properties of single-molecule junctions of the exohedral fullerene C50Cl10 connected to gold electrodes and found that it indeed possesses a positive Seebeck coefficient. Furthermore, in common with C60, the Seebeck coefficient can be increased by placing more than one C50Cl10 in series. For a single C50Cl10, we find S = +8 μV K(-1) and for two C50Cl10's in series we find S = +30 μV K(-1). We also find that the C50Cl10 monomer and dimer have power factors of 0.5 × 10(-5) W m(-1) K(-2) and 6.0 × 10(-5) W m(-1) K(-2) respectively. These results demonstrate that exohedral fullerenes provide a new class of thermoelectric materials with desirable properties, which complement those of all-carbon fullerenes, thereby enabling the boosting of the thermovoltage in all-fullerene tandem structures.
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Affiliation(s)
- Nasser Almutlaq
- Department of physics, Lancaster University, Lancaster LA1 4YB, UK. and Department of Physics, Northern Border University, Saudi Arabia
| | - Qusiy Al-Galiby
- Department of physics, Lancaster University, Lancaster LA1 4YB, UK. and Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK and Department of physics, College of Education, Al-Qadisiyah University, Diwaniyah, 58002, IRAQ
| | - Steven Bailey
- Department of physics, Lancaster University, Lancaster LA1 4YB, UK. and Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK
| | - Colin J Lambert
- Department of physics, Lancaster University, Lancaster LA1 4YB, UK. and Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK
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