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Xu J, Li YK, Janssens E, Hou GL. Multifacets of Fullerene-Metal Clusters: From Fundamental to Application. Acc Chem Res 2024; 57:1670-1683. [PMID: 38654495 DOI: 10.1021/acs.accounts.4c00130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
ConspectusBuckminsterfullerene, C60, was discovered through a prominent mass peak containing 60 atoms produced from laser vaporization of graphite, driven by Kroto's interest in understanding the formation mechanisms of carbon-containing molecules in space. Inspired by the geodesic dome-shaped architecture designed by Richard Buckminster Fuller, after whom the particle was named, C60 was found to have a football-shaped structure comprising 20 hexagons and 12 pentagons. It sparked worldwide interest in understanding this new carbon allotrope, resulting in the awarding of the Noble Prize in Chemistry to Smalley, Kroto, and Curl in 1996.Intrinsically, C60 is an exceptional species because of its high stability and electron-accepting ability and its structural tunability by decorating or substituting either on its exterior surface or interior hollow cavity. For example, metal-decorated fullerene complexes have found important applications ranging from superconductivity, nanoscale electronic devices, and organic photovoltaic cells to catalysis and biomedicine. Compared to the large body of studies on atoms and molecules encapsulated by C60, studies on the exteriorly modified fullerenes, i.e., exohedral fullerenes, are scarcer. Surprisingly, to date, uncertainty exists about a fundamental question: what is the preferable exterior binding site of different kinds of single atoms on the C60 surface?In recent years, we have developed an experimental protocol to synthesize the desired fullerene-metal clusters and to record their infrared spectra via messenger-tagged infrared multiple photon dissociation spectroscopy. With complementary quantum chemical calculations and molecular dynamics simulations, we determined that the most probable binding site of a metal, specifically a vanadium cation, on C60 is above a pentagonal center in an η5 fashion. We explored the bonding nature between C60 and V+ and revealed that the high thermal stability of this cluster originates from large orbital and electrostatic interactions. Through comparing the measured infrared spectra of [C60-Metal]+ with the observational Spitzer data of several fullerene-rich planetary nebulae, we proposed that the complexes formed by fullerene and cosmically abundant metals, for example, iron, are promising carriers of astronomical unidentified spectroscopic features. This opens the door for a real consideration of Kroto's 30-year-old hypothesis that complexes involving cosmically abundant elements and C60 exhibit strong charge-transfer bands, similar to those of certain unidentified astrophysical spectroscopic features. We compiled a VibFullerene database and extracted a set of vibrational frequencies and intensities for fullerene derivatives to facilitate their potential detection by the James Webb Space Telescope. In addition, we showed that upon infrared irradiation C60V+ can efficiently catalyze water splitting to generate H2. This finding is attributed to the novel geometric-electronic effects of C60, acting as "hydrogen shuttle" and "electron sponge", which illustrates the important role of carbon-based supports in single-atom catalysts. Our work not only unveils the basic structures and bonding nature of fullerene-metal clusters but also elucidates their potential importance in astrophysics, astrochemistry, and catalysis, showing the multifaceted character of this class of clusters. More exciting and interesting aspects of the fullerene-metal clusters, such as ultrafast charge-transfer dynamics between fullerene and metal and their relevance to designing hybrid fullerene-metal junctions for electronic devices, are awaiting exploration.
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Affiliation(s)
- Jianzhi Xu
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, 710049 Shaanxi, China
| | - Ya-Ke Li
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, 710049 Shaanxi, China
| | - Ewald Janssens
- Quantum Solid-State Physics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, Leuven 3001, Belgium
| | - Gao-Lei Hou
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, 710049 Shaanxi, China
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2
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He P, Daaoub AHS, Sangtarash S, Sadeghi H, Yoon HJ. Thermopower in Underpotential Deposition-Based Molecular Junctions. NANO LETTERS 2024; 24:1988-1995. [PMID: 38270106 PMCID: PMC10870761 DOI: 10.1021/acs.nanolett.3c04438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/18/2024] [Accepted: 01/18/2024] [Indexed: 01/26/2024]
Abstract
Underpotential deposition (UPD) is an intriguing means for tailoring the interfacial electronic structure of an adsorbate at a substrate. Here we investigate the impact of UPD on thermoelectricity occurring in molecular tunnel junctions based on alkyl self-assembled monolayers (SAMs). We observed noticeable enhancements in the Seebeck coefficient of alkanoic acid and alkanethiol monolayers, by up to 2- and 4-fold, respectively, upon replacement of a conventional Au electrode with an analogous bimetallic electrode, Cu UPD on Au. Quantum transport calculations indicated that the increased Seebeck coefficients are due to the UPD-induced changes in the shape or position of transmission resonances corresponding to gateway orbitals, which depend on the choice of the anchor group. Our work unveils UPD as a potent means for altering the shape of the tunneling energy barrier at the molecule-electrode contact of alkyl SAM-based junctions and hence enhancing thermoelectric performance.
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Affiliation(s)
- Peng He
- Department
of Chemistry, Korea University, Seoul 02841, Korea
| | - Abdalghani H. S. Daaoub
- Device
Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, U.K.
| | - Sara Sangtarash
- Device
Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, U.K.
| | - Hatef Sadeghi
- Device
Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, U.K.
| | - Hyo Jae Yoon
- Department
of Chemistry, Korea University, Seoul 02841, Korea
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3
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Xu J, Bakker JM, Lushchikova OV, Lievens P, Janssens E, Hou GL. Pentagon, Hexagon, or Bridge? Identifying the Location of a Single Vanadium Cation on Buckminsterfullerene Surface. J Am Chem Soc 2023; 145:22243-22251. [PMID: 37757468 DOI: 10.1021/jacs.3c08451] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Buckminsterfullerene C60 has received extensive research interest since its discovery. In addition to its interesting intrinsic properties of exceptional stability and electron-accepting ability, the broad chemical tunability by decoration or substitution on the C60-fullerene surface makes it a fascinating molecule. However, to date, there is uncertainty about the binding location of such decorations on the C60 surface, even for a single adsorbed metal atom. In this work, we report the gas-phase synthesis of the C60V+ complex and its in situ characterization by mass spectrometry and infrared spectroscopy with the help of quantum chemical calculations and molecular dynamics simulations. We identify the most probable binding position of a vanadium cation on C60 above a pentagon center in an η5-fashion, demonstrate a high thermal stability for this complex, and explore the bonding nature between C60 and the vanadium cation, revealing that large orbital and electrostatic interactions lie at the origin of the stability of the η5-C60V+ complex.
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Affiliation(s)
- Jianzhi Xu
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China
| | - Joost M Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, HFML-FELIX, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Olga V Lushchikova
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, HFML-FELIX, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Peter Lievens
- Quantum Solid-State Physics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Ewald Janssens
- Quantum Solid-State Physics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Gao-Lei Hou
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China
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4
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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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5
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Park S, Jang J, Tanaka Y, Yoon HJ. High Seebeck Coefficient Achieved by Multinuclear Organometallic Molecular Junctions. NANO LETTERS 2022; 22:9693-9699. [PMID: 36441166 DOI: 10.1021/acs.nanolett.2c03974] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
This paper describes the thermoelectric properties of molecular junctions incorporating multinuclear ruthenium alkynyl complexes that comprise Ru(dppe)2 [dppe = 1,2-bis(diphenylphosphino)ethane] fragments and diethylnyl aromatic bridging ligands with thioether anchors. Using the liquid metal technique, the Seebeck coefficient was examined as a function of metal nuclearity, oxidation state, and substituent on the organic ligand backbone. High Seebeck coefficients up to 73 μV/K and appreciable thermal stability with thermovoltage up to ∼3.3 mV at a heating temperature of 423 K were observed. An unusually high proximity of the highest occupied molecular orbital (HOMO) energy level to the Fermi level was revealed to give the remarkable thermoelectric performance as suggested by combined experiments and calculations. This work offers important insights into the development of molecular-scale devices for efficient thermoregulation and heat-to-electricity conversion.
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Affiliation(s)
- Sohyun Park
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Jiung Jang
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Yuya Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul 02841, Korea
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6
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Advances in Thermoelectric Composites Consisting of Conductive Polymers and Fillers with Different Architectures. Molecules 2022; 27:molecules27206932. [PMID: 36296524 PMCID: PMC9612169 DOI: 10.3390/molecules27206932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 11/24/2022] Open
Abstract
Stretchable wireless power is in increasingly high demand in fields such as smart devices, flexible robots, and electronic skins. Thermoelectric devices are able to convert heat into electricity due to the Seebeck effect, making them promising candidates for wearable electronics. Therefore, high-performance conductive polymer-based composites are urgently required for flexible wearable thermoelectric devices for the utilization of low-grade thermal energy. In this review, mechanisms and optimization strategies for polymer-based thermoelectric composites containing fillers of different architectures will be introduced, and recent advances in the development of such thermoelectric composites containing 0- to 3-dimensional filler components will be presented and outlooked.
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7
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Kaur S, Sharma H, Jindal VK, Bubanja V, Mudahar I. Ab initio study of nitrogen and boron doped dimers. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2100294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Sandeep Kaur
- Department of Physics, Punjabi University, Patiala, India
| | - Hitesh Sharma
- Department of Applied Sciences, IKG Panjab Technical University, Kapurthala, Punjab, India
| | - V. K. Jindal
- Department of Physics, Panjab University, Chandigarh, India
| | - Vladimir Bubanja
- Measurement Standards Laboratory of New Zealand, Callaghan Innovation, Lower Hutt, Wellington, New Zealand
- The Dodd-Walls Centre for Photonic and Quantum Technologies, University of Otago, Dunedin, New Zealand
| | - Isha Mudahar
- Department of Physics, Punjabi University, Patiala, Punjab, India
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8
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Park S, Kang S, Yoon HJ. Thermopower of Molecular Junction in Harsh Thermal Environments. NANO LETTERS 2022; 22:3953-3960. [PMID: 35575639 DOI: 10.1021/acs.nanolett.2c00422] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Molecular junctions can be miniaturized devices for heat-to-electricity conversion application, yet these operate only in mild thermal environments (less than 323 K) because thiol, the most widely used anchor moiety for chemisorption of active molecules onto surface of electrode, easily undergoes thermal degradation. N-Heterocyclic carbene (NHC) can be an alternative to traditional thiol anchor for producing ultrastable thermoelectric molecular junctions. Our experiments showed that the NHC-based molecular junctions withstood remarkably high temperatures up to 573 K, exhibiting consistent Seebeck effect and thermovoltage up to approximately |1900 μV|. Our work advances our understanding of molecule-electrode contact in the Seebeck effect, providing a roadmap for constructing robust and efficient organic thermoelectric devices.
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Affiliation(s)
- Sohyun Park
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Seohyun Kang
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul 02841, Korea
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9
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Nadtochiy A, Kozachenko V, Korotchenkov O, Schlosser V. Nickel-Fullerene Nanocomposites as Thermoelectric Materials. NANOMATERIALS 2022; 12:nano12071163. [PMID: 35407281 PMCID: PMC9000331 DOI: 10.3390/nano12071163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/23/2022] [Accepted: 03/29/2022] [Indexed: 02/04/2023]
Abstract
Nickel films with nanovoids filled with fullerene molecules have been fabricated. The thermoelectric properties of the nanocomposites have been measured from room temperature down to about 30 K. The main idea is that the phonon scattering can be enhanced at the C60/matrix heterointerface. The distribution of atoms within the Ni and Ni-C60 layers has been characterized by Auger depth profiling. The morphology of the grown samples has been checked using cross-sectional scanning electron microscopy (SEM). The Seebeck coefficient and electrical conductivity have been addressed employing an automatic home-built measuring system. It has been found that nanostructuring using Ar+ ion treatment increases the thermopower magnitude over the entire temperature range. Incorporating C60 into the resulting voids further increased the thermopower magnitude below ≈200 K. A maximum increase in the Seebeck coefficient has been measured up to four times in different fabricated samples. This effect is attributed to enhanced scattering of charge carriers and phonons at the Ni/C60 boundary.
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Affiliation(s)
- Andriy Nadtochiy
- Department of Physics, Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine; (A.N.); (V.K.)
| | - Viktor Kozachenko
- Department of Physics, Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine; (A.N.); (V.K.)
| | - Oleg Korotchenkov
- Department of Physics, Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine; (A.N.); (V.K.)
- Correspondence: (O.K.); (V.S.); Tel.: +43-1-4277-72611 (V.S.)
| | - Viktor Schlosser
- Department of Electronic Properties of Materials, Faculty of Physics, University of Vienna, A-1090 Wien, Austria
- Correspondence: (O.K.); (V.S.); Tel.: +43-1-4277-72611 (V.S.)
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10
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Park S, Yoon HJ. Thermal and Thermoelectric Properties of SAM-Based Molecular Junctions. ACS APPLIED MATERIALS & INTERFACES 2021; 14:22818-22825. [PMID: 34961308 DOI: 10.1021/acsami.1c20840] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In molecular thermoelectrics, the thermopower of molecular junctions is closely interlinked with their thermal properties; however, the detailed relationship between them remains uncertain. This study systematically investigates the thermal properties of self-assembled monolayer (SAM)-based molecular junctions and relates them to the thermoelectric performance of the junctions. The electrode temperatures for the bare AuTS, AuTS/EGaIn, and AuTS/TPT SAM//Ga2O3/EGaIn samples placed on a hot chuck were measured under different conditions, such as air vs vacuum and the presence and absence of thermal grease, which generates a heat conduction channel from a hot chuck to gold. It was revealed that the SAM was the most efficient thermal resistor, which was responsible for the creation of a temperature differential (ΔT) across the junction; ΔT in an air atmosphere is overestimated to some extent, and air mainly contributes to large dispersions of thermovoltage (ΔV) data. While junction measurements in air were possible at low ΔT (up to 13 K), the new optimal condition, under a vacuum and with thermal grease, allowed us to examine a wide temperature range up to ΔT = 40 K and obtain a more reliable Seebeck coefficient (S, μV/K). The value of S under the new condition was ∼1.4 times higher than that measured in air without thermal grease. Our study shows the potential of liquid-metal-based junctions to reliably investigate heat conduction across nanometer-thick organic films and elaborates on how the thermal properties of molecular junctions affect their thermoelectric performance.
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Affiliation(s)
- Sohyun Park
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul 02841, Korea
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11
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Park S, Kim HR, Kim J, Hong BH, Yoon HJ. Enhanced Thermopower of Saturated Molecules by Noncovalent Anchor-Induced Electron Doping of Single-Layer Graphene Electrode. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2103177. [PMID: 34453364 DOI: 10.1002/adma.202103177] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Enhancing thermopower is a key goal in organic and molecular thermoelectrics. Herein, it is shown that introducing noncovalent contact with a single-layer graphene (SLG) electrode improves the thermopower of saturated molecules as compared to the traditional gold-thiolate covalent contact. Thermoelectric junction measurements with a liquid-metal technique reveal that the value of Seebeck coefficient in large-area junctions based on n-alkylamine self-assembled monolayers (SAMs) on SLG is increased up to fivefold compared to the analogous junction based on n-alkanethiolate SAMs on gold. Experiments with Raman spectroscopy and field-effect transistor analysis indicate that such enhancements benefit from the creation of new in-gap states and electron doping through noncovalent interaction between the amine anchor and the SLG electrode, which leads to a reduced energy offset between the Fermi level and the transport channel. This work demonstrates that control of interfacial bonding nature in molecular junctions improves the Seebeck effect in saturated molecules.
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Affiliation(s)
- Sohyun Park
- Department of Chemistry, Korea University, Seoul, 02841, South Korea
| | - Hwa Rang Kim
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Juhee Kim
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Byung-Hee Hong
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul, 02841, South Korea
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12
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Roy TR, J JDR, Sen A. Inelastic Tunnel Transport and Nanoscale Junction Thermoelectricity with Varying Electrode Topology. ADVANCED THEORY AND SIMULATIONS 2021. [DOI: 10.1002/adts.202100054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Talem Rebeda Roy
- SRM Research Institute and Department of Physics & Nanotechnology SRM Institute of Science and Technology Chennai Tamil Nadu 603203 India
| | - John Donald Raj J
- SRM Research Institute and Department of Physics & Nanotechnology SRM Institute of Science and Technology Chennai Tamil Nadu 603203 India
| | - Arijit Sen
- SRM Research Institute and Department of Physics & Nanotechnology SRM Institute of Science and Technology Chennai Tamil Nadu 603203 India
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13
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Ismael A, Al-Jobory A, Wang X, Alshehab A, Almutlg A, Alshammari M, Grace I, Benett TLR, Wilkinson LA, Robinson BJ, Long NJ, Lambert C. Molecular-scale thermoelectricity: as simple as 'ABC'. NANOSCALE ADVANCES 2020; 2:5329-5334. [PMID: 36132050 PMCID: PMC9417915 DOI: 10.1039/d0na00772b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 01/11/2021] [Accepted: 10/06/2020] [Indexed: 05/08/2023]
Abstract
If the Seebeck coefficient of single molecules or self-assembled monolayers (SAMs) could be predicted from measurements of their conductance-voltage (G-V) characteristics alone, then the experimentally more difficult task of creating a set-up to measure their thermoelectric properties could be avoided. This article highlights a novel strategy for predicting an upper bound to the Seebeck coefficient of single molecules or SAMs, from measurements of their G-V characteristics. The theory begins by making a fit to measured G-V curves using three fitting parameters, denoted a, b, c. This 'ABC' theory then predicts a maximum value for the magnitude of the corresponding Seebeck coefficient. This is a useful material parameter, because if the predicted upper bound is large, then the material would warrant further investigation using a full Seebeck-measurement setup. On the other hand, if the upper bound is small, then the material would not be promising and this much more technically demanding set of measurements would be avoided. Histograms of predicted Seebeck coefficients are compared with histograms of measured Seebeck coefficients for six different SAMs, formed from anthracene-based molecules with different anchor groups and are shown to be in excellent agreement.
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Affiliation(s)
- Ali Ismael
- Department of Physics, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Education for Pure Science, Tikrit University Tikrit Iraq
| | - Alaa Al-Jobory
- Department of Physics, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Science, University of Anbar Anbar Iraq
| | - Xintai Wang
- Department of Physics, Lancaster University Lancaster LA1 4YB UK
| | | | - Ahmad Almutlg
- Department of Physics, Lancaster University Lancaster LA1 4YB UK
| | - Majed Alshammari
- Department of Physics, Lancaster University Lancaster LA1 4YB UK
| | - Iain Grace
- Department of Physics, Lancaster University Lancaster LA1 4YB UK
| | - Troy L R Benett
- 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
| | | | - Nicholas J Long
- Department of Chemistry, Imperial College London, MSRH White City London W12 0BZ UK
| | - Colin Lambert
- Department of Physics, Lancaster University Lancaster LA1 4YB UK
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14
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Castillo-Chará J. Density functional calculation of the molecular properties of the [Au20-C60-Au20]− (n = 0, 1, 2, 3) model complexes. COMPUT THEOR CHEM 2020. [DOI: 10.1016/j.comptc.2020.112918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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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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16
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Shirdel-Havar M, Farghadan R. Thermal magnetoresistance and spin thermopower in C 60 dimers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:285302. [PMID: 32308207 DOI: 10.1088/1361-648x/ab8154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We theoretically investigate the spin-related thermoelectric properties in C60 dimer bridged between zigzag graphene nanoribbon electrodes using the tight-binding model, equilibrium Green's function method, and Landauer-Büttiker transport formalism. By applying a thermal gradient, our proposed device could generate a notable spin thermopower. Moreover, by switching the magnetization of the electrodes, different spin currents, and giant thermal magnetoresistance (MR) can be achieved. Interestingly, various types of C60 dimers also produce a thermal MR, which is sensitively modified by the gate voltages.
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17
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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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18
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Hayati A. Heat dissipation in two-terminal Benzene junction. Mol Phys 2020. [DOI: 10.1080/00268976.2019.1653501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Amir Hayati
- Department of Science, Faculty of Imam Mohammad Bagher, Technical and Vocational University (TVU), Mazandaran, Iran
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19
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Droghetti A, Rungger I. Enhanced thermopower in covalent graphite-molecule contacts. Phys Chem Chem Phys 2020; 22:1466-1474. [PMID: 31867588 DOI: 10.1039/c9cp05474j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Seebeck effect is very attractive for technological applications as it leads to the direct conversion of heat into electricity. One of the key quantities determining the efficiency of such conversion is the thermopower S. In this paper we explore theoretically what electronic properties are responsible for the Seebeck effect in molecular junctions with graphite or graphene electrodes. We propose that S can be enhanced because of the combined effect of the dip in the density of states at the Fermi energy of these materials and the molecular resonance. Then to understand the impact of the covalent vs. non-covalent molecule-carbon bonding we calculate from first principles the electronic and transport properties of graphite/molecule/Au junctions, where both types of bonding have been reported experimentally. We ultimately predict that S is about 120 μV K-1 at room temperature for a 3,5-dimethyl-4-aminobenzene (DMAB) molecule covalently attached to the graphite electrode. This value is one order of magnitude larger than the typical values measured to date for molecular junctions and it is a signature of the direct C-C molecule-graphite bond. Finally we also demonstrate how one can control not just the absolute magnitude of S, but also its sign by designing the graphite-molecule contact. Our results lead the way towards the use of junctions with molecules covalently attached to a C-based substrate as possible new improved platforms for molecular thermoelectric devices.
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Affiliation(s)
- Andrea Droghetti
- Nano-Bio Spectroscopy Group and European Theoretical Spectroscopy Facility (ETSF), Materials Physics Center, Universidad del Pais Vasco, Av. Tolosa 72, 20018 San Sebastian, Spain.
| | - Ivan Rungger
- National Physical Laboratory, Hampton Road, TW11 0LW, UK.
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20
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Jones LO, Mosquera MA, Fu B, Schatz GC, Marks TJ, Ratner MA. Quantum Interference and Substantial Property Tuning in Conjugated Z- ortho-Regio-Resistive Organic (ZORRO) Junctions. NANO LETTERS 2019; 19:8956-8963. [PMID: 31682761 DOI: 10.1021/acs.nanolett.9b03849] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Coherence is a significant factor in nanoscale electronic insulator technology and necessitates an understanding of the structure-property relationship between constructive and destructive quantum interference. This is particularly important in organic dielectric circuitry, which is the subject of this work. It is known that molecular wires composed of (i) meta-substituted phenylene rings, (ii) cross-conjugated double bonds (orthogonal to the molecular long axis), and (iii) single bonds can dramatically reduce electrical transmission. Here we add to these tools the use of an unexplored molecular shape to create strong and counterintuitive interference: a fully conjugated molecular wire with a structure that is forced back on itself in a Z shape, thereby exhibiting remarkably low conductance (G = 0.43 × 10-9 S) even though the phenylene arrangements are ortho- rather than meta-disposed. We call these Z-shaped molecules having ultralow conduction Z-ortho-regio-resistive organics (ZORROs). Here we analyze a series of ZORRO molecules and find them to have significant insulating properties in the coherent electron-transport regime due to interfering transmission pathways in the phenylene rings. Importantly, we find that both electron-withdrawing (fluorine) and electron-donating (methoxy) substituents enhance the transmission, which is not desirable. The former is due to the suppression of the destructive quantum interference at the F site, thereby enhancing the overall transmission, much like a Büttiker probe. The latter is due to a methoxy unit resonance additive effect, akin to oxygen doping, and positively contributes to the transmission. We then examine the effects of replacing the phenylene rings with 4,5- and 3,4-disubstituted thiophenes and how this ZORRO modification further reduces the transmission. An ultralow conductance of 0.13 × 10-9 S and a relatively high dielectric constant (εr) of ∼5 are predicted for the 3,4-thiophene ZORRO derivative, which closely resembles two cross-conjugated units, making it an intriguing candidate for a gate dielectric material.
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Affiliation(s)
- Leighton O Jones
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Martín A Mosquera
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Bo Fu
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - George C Schatz
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Tobin J Marks
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Mark A Ratner
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
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21
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Jones LO, Mosquera MA, Schatz GC, Ratner MA. Molecular Junctions Inspired by Nature: Electrical Conduction through Noncovalent Nanobelts. J Phys Chem B 2019; 123:8096-8102. [PMID: 31525929 DOI: 10.1021/acs.jpcb.9b06255] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Charge transport occurs in a range of biomolecular systems, whose structures have covalent and noncovalent bonds. Understanding from these systems have yet to translate into molecular junction devices. We design junctions which have hydrogen-bonds between the edges of a series of prototype noncovalent nanobelts (NCNs) and vary the number of donor-acceptors to study their electrical properties. From frontier molecular orbitals (FMOs) and projected density of state (DOS) calculations, we found these NCN dimer junctions to have low HOMO-LUMO gaps and states at the Fermi level, suggesting these are metallic-like systems. Their conductance properties were studied with nonequilibrium Green's functions density functional theory (NEGF-DFT) and was found to decrease with cooperative H-bonding, that is, the conductance decreased as the alternating donor-acceptors around the nanobelts attenuates to a uniform distribution in the H-bonding arrays. The latter gave the highest conductance of 51.3 × 10-6 S and the Seebeck coefficient showed n-type (-36 to -39 μV K-1) behavior, while the lower conductors with alternating H-bonds are p-type (49.7 to 204 μV K-1). In addition, the NCNs have appreciable binding energies (19.8 to 46.1 kcal mol-1), implying they could form self-assembled monolayer (SAM) heterojunctions leading to a polymeric network for long-range charge transport.
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Affiliation(s)
- Leighton O Jones
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Martín A Mosquera
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - George C Schatz
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Mark A Ratner
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
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22
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Perroni CA, Cataudella V. On the Role of Local Many-Body Interactions on the Thermoelectric Properties of Fullerene Junctions. ENTROPY 2019; 21:e21080754. [PMID: 33267468 PMCID: PMC7515282 DOI: 10.3390/e21080754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 07/23/2019] [Accepted: 07/31/2019] [Indexed: 11/16/2022]
Abstract
The role of local electron–vibration and electron–electron interactions on the thermoelectric properties of molecular junctions is theoretically analyzed focusing on devices based on fullerene molecules. A self-consistent adiabatic approach is used in order to obtain a non-perturbative treatment of the electron coupling to low frequency vibrational modes, such as those of the molecule center of mass between metallic leads. The approach also incorporates the effects of strong electron–electron interactions between molecular degrees of freedom within the Coulomb blockade regime. The analysis is based on a one-level model which takes into account the relevant transport level of fullerene and its alignment to the chemical potential of the leads. We demonstrate that only the combined effect of local electron–vibration and electron–electron interactions is able to predict the correct behavior of both the charge conductance and the Seebeck coefficient in very good agreement with available experimental data.
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23
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Abstract
One of the fundamental challenges in molecular-scale sensors is the junction to junction variability leading to variations in their electrical conductance by up to a few orders of magnitude. In contrast, thermal voltage measurements of single and many molecule junctions show that this variation in the Seebeck coefficient is smaller. Particularly, the sign of the Seebeck coefficient is often resilient against conformational changes. In this paper, we demonstrate that this robust molecular feature can be utilised in an entirely new direction of discriminating molecular sensing of gas and bio-molecules. We show that the positive sign of the Seebeck coefficient in the presence of cytosine nucleobases changes to a negative one when cancerous cytosine nucleobases were absorbed on the molecular wire formed by metalloporphyrins. Furthermore, the sign of the Seebeck coefficient changes when chlorine gas interacts with the Mn-porphyrin molecular wire. The change in the sign of Seebeck coefficient is due to the formation of spin driven bound states with energies close to the Fermi energy of electrodes. Seebeck sensing is a generic concept and opens new avenues for molecular sensing with huge potential applications in the years ahead.
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Affiliation(s)
- Hatef Sadeghi
- Physics Department, Lancaster University, Lancaster LA1 4YB, UK.
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24
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Park S, Yoon HJ. New Approach for Large-Area Thermoelectric Junctions with a Liquid Eutectic Gallium-Indium Electrode. NANO LETTERS 2018; 18:7715-7718. [PMID: 30418032 DOI: 10.1021/acs.nanolett.8b03404] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A challenge in organic thermoelectrics is to relate thermoelectric performance of devices to the chemical and electronic structures of organic components inside them on a molecular scale. To this end, a reliable and reproducible platform relevant to molecular-level thermoelectric measurements is essentially needed. This paper shows a new, efficient approach for thermoelectric characterization of a large area of molecular monolayers using liquid eutectic gallium-indium (EGaIn). A cone-shaped EGaIn microelectrode permits access to noninvasive, reversible top-contact formation onto organic surfaces in ambient conditions, high yields of working devices (up to 97%), and thus statistically sufficient thermoelectric data sets (∼6000 data per sample in a few hours). We here estimated thermopowers of EGaIn (3.4 ± 0.1 μV/K) and the Ga2O3 layer (3.4 ± 0.2 μV/K) on the EGaIn conical tip and successfully validated our platform with widely studied molecules, oligophenylenethiolates. Our approach will open the door to thermoelectric large-area molecular junctions.
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Affiliation(s)
- Sohyun Park
- Department of Chemistry , Korea University , Seoul 02841 , Korea
| | - Hyo Jae Yoon
- Department of Chemistry , Korea University , Seoul 02841 , Korea
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25
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Yzambart G, Rincón-García L, Al-Jobory AA, Ismael AK, Rubio-Bollinger G, Lambert CJ, Agraït N, Bryce MR. Thermoelectric Properties of 2,7-Dipyridylfluorene Derivatives in Single-Molecule Junctions. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2018; 122:27198-27204. [PMID: 31080539 PMCID: PMC6503582 DOI: 10.1021/acs.jpcc.8b08488] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/23/2018] [Indexed: 05/03/2023]
Abstract
A series of 2,7-dipyridylfluorene derivatives have been synthesized with different substituents (2H, 2Me, 2OMe, 2CF3, and O) at the C(9) position. Experimental measurements on gold|single-molecule|gold junctions, using a modified scanning tunneling microscope-break-junction technique, show that the C(9) substituent has little effect on the conductance, although there is a more significant influence on the thermopower, with the Seebeck coefficient varying by a factor of 1.65 within the series. The combined experimental and computational study, using density functional theory calculations, provides insights into the interplay of conductance and thermopower in single-molecule junctions and is a guide for new strategies for thermopower modulation in single-molecule junctions.
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Affiliation(s)
- Gilles Yzambart
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
| | - Laura Rincón-García
- Departamento de Física de
la Materia Condensada and Condensed Matter
Physics Center (IFIMAC) and Instituto Universitario 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
| | - Alaa A. Al-Jobory
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
- Department
of Physics, College of Education for Pure Science, University of Anbar, Ramadi P.O. Box
55, Anbar, Iraq
| | - Ali K. Ismael
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
- Department
of Physics, College of Education for Pure Science, Tikrit University, Saladin P.O. Box
42, Tikrit, Iraq
| | - Gabino Rubio-Bollinger
- Departamento de Física de
la Materia Condensada and Condensed Matter
Physics Center (IFIMAC) and Instituto Universitario de Ciencia de
Materiales “Nicolás Cabrera” (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Colin J. Lambert
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
| | - Nicolás Agraït
- Departamento de Física de
la Materia Condensada and Condensed Matter
Physics Center (IFIMAC) and Instituto Universitario 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
| | - Martin R. Bryce
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
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26
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Petsagkourakis I, Tybrandt K, Crispin X, Ohkubo I, Satoh N, Mori T. Thermoelectric materials and applications for energy harvesting power generation. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2018; 19:836-862. [PMID: 31001364 PMCID: PMC6454408 DOI: 10.1080/14686996.2018.1530938] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 09/28/2018] [Accepted: 09/28/2018] [Indexed: 05/19/2023]
Abstract
Thermoelectrics, in particular solid-state conversion of heat to electricity, is expected to be a key energy harvesting technology to power ubiquitous sensors and wearable devices in the future. A comprehensive review is given on the principles and advances in the development of thermoelectric materials suitable for energy harvesting power generation, ranging from organic and hybrid organic-inorganic to inorganic materials. Examples of design and applications are also presented.
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Affiliation(s)
| | - Klas Tybrandt
- Laboratory of Organic Electronics, Linköping University, Norrköping, Sweden
| | - Xavier Crispin
- Laboratory of Organic Electronics, Linköping University, Norrköping, Sweden
| | - Isao Ohkubo
- Center for Functional Sensor & Actuator (CFSN) and International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Japan
| | - Norifusa Satoh
- Center for Functional Sensor & Actuator (CFSN) and International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Japan
| | - Takao Mori
- Center for Functional Sensor & Actuator (CFSN) and International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Japan
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan
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27
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Zhou X, Pan C, Liang A, Wang L, Wan T, Yang G, Gao C, Wong WY. Enhanced figure of merit of poly(9,9-di- n
-octylfluorene-alt-benzothiadiazole) and SWCNT thermoelectric composites by doping with FeCl 3. J Appl Polym Sci 2018. [DOI: 10.1002/app.47011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- X. Zhou
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering; Shenzhen University; Shenzhen 518060 China
| | - C. Pan
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering; Shenzhen University; Shenzhen 518060 China
| | - A. Liang
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering; Shenzhen University; Shenzhen 518060 China
| | - L. Wang
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering; Shenzhen University; Shenzhen 518060 China
| | - T. Wan
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering; Shenzhen University; Shenzhen 518060 China
| | - G. Yang
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering; Shenzhen University; Shenzhen 518060 China
| | - C. Gao
- College of Chemistry and Chemical Engineering; Shenzhen University; Shenzhen 518060 China
| | - W.-Y. Wong
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering; Shenzhen University; Shenzhen 518060 China
- Department of Applied Biology and Chemical Technology; The Hong Kong Polytechnic University; Hung Hom Hong Kong
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28
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Hnida KE, Pilarczyk K, Knutelski M, Marzec M, Gajewska M, Kosonowski A, Chlebda D, Lis B, Przybylski M. Tuning of the Seebeck Coefficient and the Electrical and Thermal Conductivity of Hybrid Materials Based on Polypyrrole and Bismuth Nanowires. Chemphyschem 2018; 19:1617-1626. [PMID: 29633465 DOI: 10.1002/cphc.201800127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Indexed: 11/06/2022]
Abstract
The growing demand for clean energy catalyzes the development of new devices capable of generating electricity from renewable energy resources. One of the possible approaches focuses on the use of thermoelectric materials (TE), which may utilize waste heat, water, and solar thermal energy to generate electrical power. An improvement of the performance of such devices may be achieved through the development of composites made of an organic matrix filled with nanostructured thermoelectric materials working in a synergetic way. The first step towards such designs requires a better understanding of the fundamental interactions between available materials. In this paper, this matter is investigated and the questions regarding the change of electrical and thermal properties of nanocomposites based on low-conductive polypyrrole enriched with bismuth nanowires of well-defined geometry and morphology is answered. It is clearly demonstrated that the electrical conductivity and the Seebeck coefficient may be tuned either simultaneously or separately within particular Bi NWs content ranges, and that both parameters may be increased at the same time.
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Affiliation(s)
- Katarzyna E Hnida
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland
| | - Kacper Pilarczyk
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland.,Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland
| | - Marcin Knutelski
- Faculty of Materials Science and Ceramics, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland
| | - Mateusz Marzec
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland
| | - Marta Gajewska
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland
| | - Artur Kosonowski
- Faculty of Materials Science and Ceramics, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland
| | - Damian Chlebda
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-060, Krakow, Poland
| | - Bartłomiej Lis
- Faculty of Energy and Fuels, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland
| | - Marek Przybylski
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland.,Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, A. Mickiewicza 30, 30-059, Krakow, Poland
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29
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Goulart M, Kuhn M, Martini P, Chen L, Hagelberg F, Kaiser A, Scheier P, Ellis AM. Highly Stable [C 60AuC 60] +/- Dumbbells. J Phys Chem Lett 2018; 9:2703-2706. [PMID: 29722981 PMCID: PMC5964450 DOI: 10.1021/acs.jpclett.8b01047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Ionic complexes between gold and C60 have been observed for the first time. Cations and anions of the type [Au(C60)2]+/- are shown to have particular stability. Calculations suggest that these ions adopt a C60-Au-C60 sandwich-like (dumbbell) structure, which is reminiscent of [XAuX]+/- ions previously observed for much smaller ligands. The [Au(C60)2]+/- ions can be regarded as Au(I) complexes, regardless of whether the net charge is positive or negative, but in both cases, the charge transfer between the Au and C60 is incomplete, most likely because of a covalent contribution to the Au-C60 binding. The C60-Au-C60 dumbbell structure represents a new architecture in fullerene chemistry that might be replicable in synthetic nanostructures.
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Affiliation(s)
- Marcelo Goulart
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Martin Kuhn
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Paul Martini
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Lei Chen
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Frank Hagelberg
- Department
of Physics and Astronomy, East Tennessee
State University, Johnson City, Tennessee 37614, United States
| | - Alexander Kaiser
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Paul Scheier
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
- E-mail: (P.S.)
| | - Andrew M. Ellis
- Department
of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
- E-mail: (A.M.E.)
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30
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Algharagholy LAA, Pope T, Lambert CJ. Strain-induced bi-thermoelectricity in tapered carbon nanotubes. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:105304. [PMID: 29339581 DOI: 10.1088/1361-648x/aaa872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We show that carbon-based nanostructured materials are a novel testbed for controlling thermoelectricity and have the potential to underpin the development of new cost-effective environmentally-friendly thermoelectric materials. In single-molecule junctions, it is known that transport resonances associated with the discrete molecular levels play a key role in the thermoelectric performance, but such resonances have not been exploited in carbon nanotubes (CNTs). Here we study junctions formed from tapered CNTs and demonstrate that such structures possess transport resonances near the Fermi level, whose energetic location can be varied by applying strain, resulting in an ability to tune the sign of their Seebeck coefficient. These results reveal that tapered CNTs form a new class of bi-thermoelectric materials, exhibiting both positive and negative thermopower. This ability to change the sign of the Seebeck coefficient allows the thermovoltage in carbon-based thermoelectric devices to be boosted by placing CNTs with alternating-sign Seebeck coefficients in tandem.
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Affiliation(s)
- L A A Algharagholy
- Department of Physics, Lancaster University, Lancaster, United Kingdom. Department of Physics, College of Science, University of Sumer, Al Rifaee, Thi Qar, Iraq
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31
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Noori M, Sadeghi H, Al-Galiby Q, Bailey SWD, Lambert CJ. High cross-plane thermoelectric performance of metallo-porphyrin molecular junctions. Phys Chem Chem Phys 2018. [PMID: 28650012 DOI: 10.1039/c7cp02229h] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We investigated the thermoelectric properties of flat-stacked 5,15-diphenylporphyrins containing divalent metal ions Ni, Co, Cu or Zn, which are strongly coordinated with the nitrogens of pyridyl coated gold electrodes. Changing metal atom has little effect on the thermal conductance due to the phonons. The room-temperature Seebeck coefficients of these junctions are rather high, ranging from 90 μV K-1 for Cu, Ni and Zn-porphyrins to -16 μV K-1 for Co-porphyrin. These values could be further increased by lowering molecular energy levels relative to the DFT-predicted Fermi energy. In contrast, the phonon contribution to the thermal conductance of these junctions is rather insensitive to the choice of metal atom. The thermopower, thermal conductance and electrical conductance combined to yield the room-temperature values for the thermoelectric figure of merit ZT ranging from 1.6 for Cu porphyrin to ∼0.02 for Ni-porphyrin.
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Affiliation(s)
- Mohammed Noori
- Quantum Technology Centre, Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK.
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32
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Sangtarash S, Sadeghi H, Lambert CJ. Connectivity-driven bi-thermoelectricity in heteroatom-substituted molecular junctions. Phys Chem Chem Phys 2018; 20:9630-9637. [PMID: 29578231 DOI: 10.1039/c8cp00381e] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
To improve the thermoelectric performance of molecular junctions formed by polyaromatic hydrocarbon (PAH) cores, we present a new strategy for enhancing their Seebeck coefficient by utilizing connectivities with destructive quantum interference combined with heteroatom substitution.
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Affiliation(s)
- Sara Sangtarash
- Quantum Technology Centre, Department of Physics, Lancaster University
- LA14YB Lancaster
- UK
| | - Hatef Sadeghi
- Quantum Technology Centre, Department of Physics, Lancaster University
- LA14YB Lancaster
- UK
| | - Colin J. Lambert
- Quantum Technology Centre, Department of Physics, Lancaster University
- LA14YB Lancaster
- UK
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33
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Gehring P, Harzheim A, Spièce J, Sheng Y, Rogers G, Evangeli C, Mishra A, Robinson BJ, Porfyrakis K, Warner JH, Kolosov OV, Briggs GAD, Mol JA. Field-Effect Control of Graphene-Fullerene Thermoelectric Nanodevices. NANO LETTERS 2017; 17:7055-7061. [PMID: 28982009 DOI: 10.1021/acs.nanolett.7b03736] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Although it was demonstrated that discrete molecular levels determine the sign and magnitude of the thermoelectric effect in single-molecule junctions, full electrostatic control of these levels has not been achieved to date. Here, we show that graphene nanogaps combined with gold microheaters serve as a testbed for studying single-molecule thermoelectricity. Reduced screening of the gate electric field compared to conventional metal electrodes allows control of the position of the dominant transport orbital by hundreds of meV. We find that the power factor of graphene-fullerene junctions can be tuned over several orders of magnitude to a value close to the theoretical limit of an isolated Breit-Wigner resonance. Furthermore, our data suggest that the power factor of an isolated level is only given by the tunnel coupling to the leads and temperature. These results open up new avenues for exploring thermoelectricity and charge transport in individual molecules and highlight the importance of level alignment and coupling to the electrodes for optimum energy conversion in organic thermoelectric materials.
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Affiliation(s)
- Pascal Gehring
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Achim Harzheim
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Jean Spièce
- Physics Department, Lancaster University , Lancaster LA1 4YB, United Kingdom
| | - Yuewen Sheng
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Gregory Rogers
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | | | - Aadarsh Mishra
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Benjamin J Robinson
- Physics Department, Lancaster University , Lancaster LA1 4YB, United Kingdom
- Materials Science Institute, Lancaster University , Lancaster, LA1 4YW, United Kingdom
| | - Kyriakos Porfyrakis
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Jamie H Warner
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Oleg V Kolosov
- Physics Department, Lancaster University , Lancaster LA1 4YB, United Kingdom
| | - G Andrew D Briggs
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Jan A Mol
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
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34
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Noori M, Sadeghi H, Lambert CJ. High-performance thermoelectricity in edge-over-edge zinc-porphyrin molecular wires. NANOSCALE 2017; 9:5299-5304. [PMID: 28398431 DOI: 10.1039/c6nr09598d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
If high efficiency organic thermoelectric materials could be identified, then these would open the way to a range of energy harvesting technologies and Peltier coolers using flexible and transparent thin-film materials. We have compared the thermoelectric properties of three zinc porphyrin (ZnP) dimers and a ZnP monomer and found that the "edge-over-edge" dimer formed from stacked ZnP rings possesses a high electrical conductance, negligible phonon thermal conductance and a high Seebeck coefficient of the order of 300 μV K-1. These combine to yield a predicted room-temperature figure of merit of ZT ≈ 4, which is the highest room-temperature ZT ever reported for a single organic molecule. This high value of ZT is a consequence of the low phonon thermal conductance arising from the stacked nature of the porphyrin rings, which hinders phonon transport through the edge-over-edge molecule and enhances the Seebeck coefficient.
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Affiliation(s)
- Mohammed Noori
- Quantum Technology Centre, Department of Physics, Lancaster University, Lancaster LA1 4YB, UK. and Department of Physics, College of Science, Thi-Qar University, Thi-Qar, Iraq
| | - Hatef Sadeghi
- Quantum Technology Centre, Department of Physics, Lancaster University, Lancaster LA1 4YB, UK.
| | - Colin J Lambert
- Quantum Technology Centre, Department of Physics, Lancaster University, Lancaster LA1 4YB, UK.
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35
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Lavrentiev V, Stupakov A, Lavrentieva I, Motylenko M, Barchuk M, Rafaja D. Evidence of interface exchange magnetism in self-assembled cobalt-fullerene nanocomposites exposed to air. NANOTECHNOLOGY 2017; 28:125704. [PMID: 28145895 DOI: 10.1088/1361-6528/aa5d73] [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
We report on the establishing of an exclusive magnetic effect in air-exposed CoxC60 nanocomposites (x > 2) created through self-assembling in the depositing mixture. In order to verify the influence of ambient air on the CoxC60 mixture film, we have studied in detail the film magnetization at rather low temperatures, which provides their ferromagnetic behavior. Tracing the possible exchange bias effect, we distinguished a clear vertical shift of the hysteresis loops recorded for the air-exposed CoxC60 films in the field cooling (FC) regime. The detected vertical shift of the FC loops is caused by an uncompensated magnetic moment M u induced by exchange coupling of the Co spins at the Co/CoO interface. This interface arises due to the oxidation of small Co clusters distributed in a C60-based matrix of self-assembled composite films, which occurs during air exposure. The core-shell structure of the Co/CoO magnetic clusters (about 2-3 nm in size) consisting of a ε-Co core and fcc-CoO shell was confirmed by means of transmission electron microscopy. Established interface magnetism testifies to a composite nanostructure in the CoxC60 mixture film with x > 2 and explains the influence of air exposure on the film structure. The discovered magnetic effect implies a new application potential for cobalt-fullerene composites in sensors and catalysis.
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Affiliation(s)
- V Lavrentiev
- Nuclear Physics Institute CAS, Rez-130, Husinec 25068, Czechia
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36
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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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37
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Tsutsui M, Yokota K, Morikawa T, Taniguchi M. Roles of vacuum tunnelling and contact mechanics in single-molecule thermopower. Sci Rep 2017; 7:44276. [PMID: 28281684 PMCID: PMC5345045 DOI: 10.1038/srep44276] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 02/06/2017] [Indexed: 11/26/2022] Open
Abstract
Molecular junction is a chemically-defined nanostructure whose discrete electronic states are expected to render enhanced thermoelectric figure of merit suitable for energy-harvesting applications. Here, we report on geometrical dependence of thermoelectricity in metal-molecule-metal structures. We performed simultaneous measurements of the electrical conductance and thermovoltage of aromatic molecules having different anchoring groups at room temperature in vacuum. We elucidated the mutual contributions of vacuum tunnelling on thermoelectricity in the short molecular bridges. We also found stretching-induced thermoelectric voltage enhancement in thiol-linked single-molecule bridges along with absence of the pulling effects in diamine counterparts, thereby suggested that the electromechanical effect would be a rather universal phenomenon in Au-S anchored molecular junctions that undergo substantial metal-molecule contact elongation upon stretching. The present results provide a novel concept for molecular design to achieve high thermopower with single-molecule junctions.
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Affiliation(s)
- Makusu Tsutsui
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Kazumichi Yokota
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Takanori Morikawa
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Masateru Taniguchi
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
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38
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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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39
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Szwejkowski CJ, Giri A, Warzoha R, Donovan BF, Kaehr B, Hopkins PE. Molecular Tuning of the Vibrational Thermal Transport Mechanisms in Fullerene Derivative Solutions. ACS NANO 2017; 11:1389-1396. [PMID: 28112951 DOI: 10.1021/acsnano.6b06499] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Control over the thermal conductance from excited molecules into an external environment is essential for the development of customized photothermal therapies and chemical processes. This control could be achieved through molecule tuning of the chemical moieties in fullerene derivatives. For example, the thermal transport properties in the fullerene derivatives indene-C60 monoadduct (ICMA), indene-C60 bisadduct (ICBA), [6,6]-phenyl C61 butyric acid methyl ester (PCBM), [6,6]-phenyl C61 butyric acid butyl ester (PCBB), and [6,6]-phenyl C61 butyric acid octyl ester (PCBO) could be tuned by choosing a functional group such that its intrinsic vibrational density of states bridge that of the parent molecule and a liquid. However, this effect has never been experimentally realized for molecular interfaces in liquid suspensions. Using the pump-probe technique time domain thermotransmittance, we measure the vibrational relaxation times of photoexcited fullerene derivatives in solutions and calculate an effective thermal boundary conductance from the opto-thermally excited molecule into the liquid. We relate the thermal boundary conductance to the vibrational modes of the functional groups using density of states calculations from molecular dynamics. Our findings indicate that the attachment of an ester group to a C60 molecule, such as in PCBM, PCBB, and PCBO, provides low-frequency modes which facilitate thermal coupling with the liquid. This offers a channel for heat flow in addition to direct coupling between the buckyball and the liquid. In contrast, the attachment of indene rings to C60 does not supply the same low-frequency modes and, thus, does not generate the same enhancement in thermal boundary conductance. Understanding how chemical functionalization of C60 affects the vibrational thermal transport in molecule/liquid systems allows the thermal boundary conductance to be manipulated and adapted for medical and chemical applications.
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Affiliation(s)
| | | | - Ronald Warzoha
- Mechanical Engineering Department, United States Naval Academy , Annapolis, Maryland 21402, United States
| | | | - Bryan Kaehr
- Advanced Materials Laboratory, Sandia National Laboratories , Albuquerque, New Mexico 87185, United States
- Department of Chemical and Biological Engineering, University of New Mexico , Albuquerque, New Mexico 87131, United States
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40
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Komoto Y, Isshiki Y, Fujii S, Nishino T, Kiguchi M. Evaluation of the Electronic Structure of Single-Molecule Junctions Based on Current-Voltage and Thermopower Measurements: Application to C 60 Single-Molecule Junction. Chem Asian J 2017; 12:440-445. [PMID: 28035743 DOI: 10.1002/asia.201601392] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/28/2016] [Indexed: 11/06/2022]
Abstract
The electronic structure of molecular junctions has a significant impact on their transport properties. Despite the decisive role of the electronic structure, a complete characterization of the electronic structure remains a challenge. This is because there is no straightforward way of measuring electron spectroscopy for an individual molecule trapped in a nanoscale gap between two metal electrodes. Herein, a comprehensive approach to obtain a detailed description of the electronic structure in single-molecule junctions based on the analysis of current-voltage (I-V) and thermoelectric characteristics is described. It is shown that the electronic structure of the prototypical C60 single-molecule junction can be resolved by analyzing complementary results of the I-V and thermoelectric measurement. This combined approach confirmed that the C60 single-molecule junction was highly conductive with molecular electronic conductances of 0.033 and 0.003 G0 and a molecular Seebeck coefficient of -12 μV K-1 . In addition, we revealed that charge transport was mediated by a LUMO whose energy level was located 0.5≈0.6 eV above the Fermi level of the Au electrode.
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Affiliation(s)
- Yuki Komoto
- Department of Chemistry, Graduate School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Yuji Isshiki
- Department of Chemistry, Graduate School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Shintaro Fujii
- Department of Chemistry, Graduate School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Tomoaki Nishino
- Department of Chemistry, Graduate School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Manabu Kiguchi
- Department of Chemistry, Graduate School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
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41
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Majumdar S, Malen JA, McGaughey AJH. Cooperative Molecular Behavior Enhances the Thermal Conductance of Binary Self-Assembled Monolayer Junctions. NANO LETTERS 2017; 17:220-227. [PMID: 28073270 DOI: 10.1021/acs.nanolett.6b03894] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The effect of the local molecular environment on thermal transport through organic-inorganic heterojunctions is investigated using binary self-assembled monolayer (SAM) junctions built from a mixture of alkanethiol and alkanedithiol species sandwiched between gold leads. Thermoreflectance measurements and molecular dynamics simulations demonstrate that the thermal conductances of the binary SAM junctions vary with molecular composition and are greater than predictions of a parallel resistance model. The enhancement results from increased thermal transport through the alkanethiols, whose terminal methyl groups are confined by the anchored alkanedithiols. This confinement effect extends over length scales that are more than twice the range of the van der Waals interactions between molecules and are commensurate to the sizes of experimentally observed molecular domains. Conversely, for a partially packed (i.e., submonolayer) alkanedithiol unary SAM, increasing the molecular packing density decreases the per molecule thermal conductance. This finding indicates that thermal transport measurements of SAMs cannot be used to predict the thermal transport properties of single molecules.
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Affiliation(s)
- Shubhaditya Majumdar
- Department of Mechanical Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Jonathan A Malen
- Department of Mechanical Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Materials Science and Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Alan J H McGaughey
- Department of Mechanical Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Materials Science and Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
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42
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Liu Y, Xu L, Zhao C, Shao M, Hu B. Tuning the Seebeck effect in C60-based hybrid thermoelectric devices through temperature-dependent surface polarization and thermally-modulated interface dipoles. Phys Chem Chem Phys 2017; 19:14793-14800. [DOI: 10.1039/c7cp01736g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tuning the Seebeck effect through polarization and interface dipoles.
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Affiliation(s)
- Yuchun Liu
- Wu Han National Laboratory for Optoelectronics
- Huazhong University of Science and Technology
- Wu Han 430074
- China
| | - Ling Xu
- Wu Han National Laboratory for Optoelectronics
- Huazhong University of Science and Technology
- Wu Han 430074
- China
| | - Chen Zhao
- Wu Han National Laboratory for Optoelectronics
- Huazhong University of Science and Technology
- Wu Han 430074
- China
| | - Ming Shao
- College of Science
- Beijing Jiaotong University
- Beijing 1000444
- China
| | - Bin Hu
- Wu Han National Laboratory for Optoelectronics
- Huazhong University of Science and Technology
- Wu Han 430074
- China
- College of Science
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43
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Perroni CA, Ninno D, Cataudella V. Thermoelectric efficiency of molecular junctions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:373001. [PMID: 27420149 DOI: 10.1088/0953-8984/28/37/373001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Focus of the review is on experimental set-ups and theoretical proposals aimed to enhance thermoelectric performances of molecular junctions. In addition to charge conductance, the thermoelectric parameter commonly measured in these systems is the thermopower, which is typically rather low. We review recent experimental outcomes relative to several junction configurations used to optimize the thermopower. On the other hand, theoretical calculations provide estimations of all the thermoelectric parameters in the linear and non-linear regime, in particular of the thermoelectric figure of merit and efficiency, completing our knowledge of molecular thermoelectricity. For this reason, the review will mainly focus on theoretical studies analyzing the role of not only electronic, but also of the vibrational degrees of freedom. Theoretical results about thermoelectric phenomena in the coherent regime are reviewed focusing on interference effects which play a significant role in enhancing the figure of merit. Moreover, we review theoretical studies including the effects of molecular many-body interactions, such as electron-vibration couplings, which typically tend to reduce the efficiency. Since a fine tuning of many parameters and coupling strengths is required to optimize the thermoelectric conversion in molecular junctions, new theoretically proposed set-ups are discussed in the conclusions.
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Affiliation(s)
- C A Perroni
- CNR-SPIN and Physics Department 'Ettore Pancini', Universita' degli Studi di Napoli 'Federico II', Complesso Universitario Monte S. Angelo, Via Cintia, I-80126 Napoli, Italy
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44
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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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Nocera A, Perroni CA, Ramaglia VM, Cataudella V. Charge and heat transport in soft nanosystems in the presence of time-dependent perturbations. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:439-64. [PMID: 27335736 PMCID: PMC4901550 DOI: 10.3762/bjnano.7.39] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 02/08/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Soft nanosystems are electronic nanodevices, such as suspended carbon nanotubes or molecular junctions, whose transport properties are modulated by soft internal degrees of freedom, for example slow vibrational modes. Effects of the electron-vibration coupling on the charge and heat transport of soft nanoscopic systems are theoretically investigated in the presence of time-dependent perturbations, such as a forcing antenna or pumping terms between the leads and the nanosystem. A well-established approach valid for non-equilibrium adiabatic regimes is generalized to the case where external time-dependent perturbations are present. Then, a number of relevant applications of the method are reviewed for systems composed by a quantum dot (or molecule) described by a single electronic level coupled to a vibrational mode. RESULTS Before introducing time-dependent perturbations, the range of validity of the adiabatic approach is discussed showing that a very good agreement with the results of an exact quantum calculation is obtained in the limit of low level occupation. Then, we show that the interplay between the low frequency vibrational modes and the electronic degrees of freedom affects the thermoelectric properties within the linear response regime finding out that the phonon thermal conductance provides an important contribution to the figure of merit at room temperature. Our work has been stimulated by recent experimental results on carbon nanotube electromechanical devices working in the semiclassical regime (resonator frequencies in the megahertz range compared to an electronic hopping frequency of the order of tens of gigahertz) with extremely high quality factors. The nonlinear vibrational regime induced by the external antenna in such systems has been discussed within the non-perturbative adiabatic approach reproducing quantitatively the characteristic asymmetric shape of the current-frequency curves. Within the same set-up, we have proved that the antenna is able to pump sufficient charge close to the mechanical resonance making single-parameter adiabatic charge pumping feasible in carbon nanotube resonators. The pumping mechanism that we observe is different from that acting in the two parameter pumping and, instead, it is based on an important dynamic adjustment of the mechanical motion of the nanotube to the external drive in the weakly nonlinear regime. Finally, stochastic forces induced by quantum and thermal fluctuations due to the electron charging of the quantum dot are shown to affect in a significant way a Thouless charge pump realized with an elastically deformable quantum dot. In this case, the pumping mechanism is also shown to be magnified when the frequency of the external drive is resonant with the proper frequency of the deformable quantum dot. In this regime, the pumping current is not strongly reduced by the temperature, giving a measurable effect. CONCLUSION Aim of this review has been to discuss common features of different soft nanosystems under external drive. The most interesting effects induced by time-dependent perturbations are obtained when the external forcing is nearly resonant with the slow vibrational modes. Indeed, not only the external forcing can enhance the electronic response, but it also induces nonlinear regimes where the interplay between electronic and vibrational degrees of freedom plays a major role.
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Affiliation(s)
- Alberto Nocera
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Carmine Antonio Perroni
- CNR-SPIN and Department of Physics “Ettore Pancini”, Universita’ degli Studi di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, Via Cintia, I-80126 Napoli, Italy
| | - Vincenzo Marigliano Ramaglia
- CNR-SPIN and Department of Physics “Ettore Pancini”, Universita’ degli Studi di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, Via Cintia, I-80126 Napoli, Italy
| | - Vittorio Cataudella
- CNR-SPIN and Department of Physics “Ettore Pancini”, Universita’ degli Studi di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, Via Cintia, I-80126 Napoli, Italy
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Affiliation(s)
- Gemma C Solomon
- Nano-Science Center and in the Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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Rincón-García L, Ismael AK, Evangeli C, Grace I, Rubio-Bollinger G, Porfyrakis K, Agraït N, Lambert CJ. Molecular design and control of fullerene-based bi-thermoelectric materials. NATURE MATERIALS 2016; 15:289-93. [PMID: 26641017 DOI: 10.1038/nmat4487] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/26/2015] [Indexed: 05/03/2023]
Abstract
Molecular junctions are a versatile test bed for investigating nanoscale thermoelectricity and contribute to the design of new cost-effective environmentally friendly organic thermoelectric materials. It was suggested that transport resonances associated with discrete molecular levels could play a key role in thermoelectric performance, but no direct experimental evidence has been reported. Here we study single-molecule junctions of the endohedral fullerene Sc3N@C80 connected to gold electrodes using a scanning tunnelling microscope. We find that the magnitude and sign of the thermopower depend strongly on the orientation of the molecule and on applied pressure. Our calculations show that Sc3N inside the fullerene cage creates a sharp resonance near the Fermi level, whose energetic location, and hence the thermopower, can be tuned by applying pressure. These results reveal that Sc3N@C80 is a bi-thermoelectric material, exhibiting both positive and negative thermopower, and provide an unambiguous demonstration of the importance of transport resonances in molecular junctions.
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Affiliation(s)
- Laura Rincón-García
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
| | - Ali K Ismael
- Department of Physics, Lancaster University, Lancaster LA1 4YW, UK
- Department of Physics, College of Education for Pure Science, Tikrit University, Tikreet 34001, Iraq
| | - Charalambos Evangeli
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Iain Grace
- Department of Physics, Lancaster University, Lancaster LA1 4YW, UK
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | | | - Nicolás Agraït
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
- Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster LA1 4YW, UK
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Al-Galiby QH, Sadeghi H, Algharagholy LA, Grace I, Lambert C. Tuning the thermoelectric properties of metallo-porphyrins. NANOSCALE 2016; 8:2428-2433. [PMID: 26754271 DOI: 10.1039/c5nr06966a] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We investigated the thermoelectric properties of metalloporphyrins connected by thiol anchor groups to gold electrodes. By varying the transition metal-centre over the family Mn, Co, Ni, Cu, Fe, and Zn we are able to tune the molecular energy levels relative to the Fermi energy of the electrodes. The resulting single-molecule room-temperature thermopowers range from almost zero for Co and Cu centres, to +80 μV K(-1) and +230 μV K(-1) for Ni and Zn respectively. In contrast, the thermopowers with Mn(II) or Fe(II) metal centres are negative and lie in the range -280 to -260 μV K(-1). Complexing these with a counter anion to form Fe(III) and Mn(III) changes both the sign and magnitude of their thermopowers to +218 and +95 respectively. The room-temperature power factors of Mn(II), Mn(III), Fe(III), Zn and Fe(II) porphyrins are predicted to be 5.9 × 10(-5) W m(-1) K(-2), 5.4 × 10(-4) W m(-1) K(-2), 9.5 × 10(-4) W m(-1) K(-2), 1.6 × 10(-4) W m(-1) K(-2) and 2.3 × 10(-4) W m(-1) K(-2) respectively, which makes these attractive materials for molecular-scale thermoelectric devices.
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Affiliation(s)
- Qusiy H Al-Galiby
- Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK. and Physics Department, Al-Qadisiyah University, Diwaniyah, 58002, Iraq
| | - Hatef Sadeghi
- Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK.
| | - Laith A Algharagholy
- Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK. and College of Basic Education, Sumer University, Al-Refayee, Thi-Qar 64001, Iraq
| | - Iain Grace
- Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK.
| | - Colin Lambert
- Quantum Technology Centre, Lancaster University, Lancaster LA1 4YB, UK.
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Lau CS, Sadeghi H, Rogers G, Sangtarash S, Dallas P, Porfyrakis K, Warner J, Lambert CJ, Briggs GAD, Mol JA. Redox-Dependent Franck-Condon Blockade and Avalanche Transport in a Graphene-Fullerene Single-Molecule Transistor. NANO LETTERS 2016; 16:170-176. [PMID: 26633125 DOI: 10.1021/acs.nanolett.5b03434] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report transport measurements on a graphene-fullerene single-molecule transistor. The device architecture where a functionalized C60 binds to graphene nanoelectrodes results in strong electron-vibron coupling and weak vibron relaxation. Using a combined approach of transport spectroscopy, Raman spectroscopy, and DFT calculations, we demonstrate center-of-mass oscillations, redox-dependent Franck-Condon blockade, and a transport regime characterized by avalanche tunnelling in a single-molecule transistor.
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Affiliation(s)
- Chit Siong Lau
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Hatef Sadeghi
- Quantum Technology Center, Physics Department, Lancaster University , Lancaster LA1 4YB, United Kingdom
| | - Gregory Rogers
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Sara Sangtarash
- Quantum Technology Center, Physics Department, Lancaster University , Lancaster LA1 4YB, United Kingdom
| | - Panagiotis Dallas
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Kyriakos Porfyrakis
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Jamie Warner
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Colin J Lambert
- Quantum Technology Center, Physics Department, Lancaster University , Lancaster LA1 4YB, United Kingdom
| | - G Andrew D Briggs
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Jan A Mol
- Department of Materials, University of Oxford , 16 Parks Road, Oxford OX1 3PH, United Kingdom
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Rincón-García L, Evangeli C, Rubio-Bollinger G, Agraït N. Thermopower measurements in molecular junctions. Chem Soc Rev 2016; 45:4285-306. [DOI: 10.1039/c6cs00141f] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The measurement of thermopower in molecular junctions offers complementary information to conductance measurements and is becoming essential for the understanding of transport processes at the nanoscale.
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Affiliation(s)
- Laura Rincón-García
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia
| | - Charalambos Evangeli
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Universitario de Ciencia de Materiales “Nicolás Cabrera”
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia
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