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Liao S, Zhu Y, Ye Q, Sanders S, Yang J, Alabastri A, Natelson D. Quantifying Efficiency of Remote Excitation for Surface-Enhanced Raman Spectroscopy in Molecular Junctions. J Phys Chem Lett 2023; 14:7574-7580. [PMID: 37589653 DOI: 10.1021/acs.jpclett.3c01948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) is enabled by local surface plasmon resonances (LSPRs) in metallic nanogaps. When SERS is excited by direct illumination of the nanogap, the background heating of the lattice and electrons can prevent further manipulation of the molecules. To overcome this issue, we report SERS in electromigrated gold molecular junctions excited remotely: surface plasmon polaritons (SPPs) are excited at nearby gratings, propagate to the junction, and couple to the local nanogap plasmon modes. Like direct excitation, remote excitation of the nanogap can generate both SERS emission and an open-circuit photovoltage (OCPV). We compare the SERS intensity and the OCPV in both direct and remote illumination configurations. SERS spectra obtained by remote excitation are much more stable than those obtained through direct excitation when the photon count rates are comparable. By statistical analysis of 33 devices, the coupling efficiency of remote excitation is calculated to be around 10%, consistent with the simulated energy flow.
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Affiliation(s)
- Shusen Liao
- Applied Physics Graduate Program, Smalley-Curl Institute, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Yunxuan Zhu
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Qian Ye
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Stephen Sanders
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
| | - Jiawei Yang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Alessandro Alabastri
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
| | - Douglas Natelson
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
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2
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Liu H, Chen L, Zhang H, Yang Z, Ye J, Zhou P, Fang C, Xu W, Shi J, Liu J, Yang Y, Hong W. Single-molecule photoelectron tunnelling spectroscopy. NATURE MATERIALS 2023; 22:1007-1012. [PMID: 37349394 DOI: 10.1038/s41563-023-01591-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 05/25/2023] [Indexed: 06/24/2023]
Abstract
Experimental mapping of transmission is essential for understanding and controlling charge transport through molecular devices and materials. Here we developed a single-molecule photoelectron tunnelling spectroscopy approach for mapping transmission beyond the HOMO-LUMO gap of the single diketopyrrolopyrrole molecule junction using an ultrafast-laser combined scanning tunnelling microscope-based break junction set-up at room temperature. Two resonant transport channels of ultrafast photocurrent are found by our photoelectron tunnelling spectroscopy, ranging from 1.31 eV to 1.77 eV, consistent with the LUMO + 1 and LUMO + 2 in the transmission spectrum obtained by density functional theory calculations. Moreover, we observed the modulation of resonant peaks by varying bias voltages, which demonstrates the ability to quantitatively characterize the effect of the electric field on frontier molecular orbitals. Our single-molecule photoelectron tunnelling spectroscopy offers an avenue that allows us to explore the nature of energy-dependent charge transport through single-molecule junctions.
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Affiliation(s)
- Haojie Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Lijue Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Hao Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Zhangqiang Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Jingyao Ye
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Ping Zhou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Chao Fang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Wei Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Jia Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Junyang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Ye Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China.
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3
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Tang Y, Harutyunyan H. Optical properties of plasmonic tunneling junctions. J Chem Phys 2023; 158:060901. [PMID: 36792491 DOI: 10.1063/5.0128822] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Over the last century, quantum theories have revolutionized our understanding of material properties. One of the most striking quantum phenomena occurring in heterogeneous media is the quantum tunneling effect, where carriers can tunnel through potential barriers even if the barrier height exceeds the carrier energy. Interestingly, the tunneling process can be accompanied by the absorption or emission of light. In most tunneling junctions made of noble metal electrodes, these optical phenomena are governed by plasmonic modes, i.e., light-driven collective oscillations of surface electrons. In the emission process, plasmon excitation via inelastic tunneling electrons can improve the efficiency of photon generation, resulting in bright nanoscale optical sources. On the other hand, the incident light can affect the tunneling behavior of plasmonic junctions as well, leading to phenomena such as optical rectification and induced photocurrent. Thus, plasmonic tunneling junctions provide a rich platform for investigating light-matter interactions, paving the way for various applications, including nanoscale light sources, sensors, and chemical reactors. In this paper, we will introduce recent research progress and promising applications based on plasmonic tunneling junctions.
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Affiliation(s)
- Yuankai Tang
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Hayk Harutyunyan
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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Plasmonic phenomena in molecular junctions: principles and applications. Nat Rev Chem 2022; 6:681-704. [PMID: 37117494 DOI: 10.1038/s41570-022-00423-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2022] [Indexed: 11/08/2022]
Abstract
Molecular junctions are building blocks for constructing future nanoelectronic devices that enable the investigation of a broad range of electronic transport properties within nanoscale regions. Crossing both the nanoscopic and mesoscopic length scales, plasmonics lies at the intersection of the macroscopic photonics and nanoelectronics, owing to their capability of confining light to dimensions far below the diffraction limit. Research activities on plasmonic phenomena in molecular electronics started around 2010, and feedback between plasmons and molecular junctions has increased over the past years. These efforts can provide new insights into the near-field interaction and the corresponding tunability in properties, as well as resultant plasmon-based molecular devices. This Review presents the latest advancements of plasmonic resonances in molecular junctions and details the progress in plasmon excitation and plasmon coupling. We also highlight emerging experimental approaches to unravel the mechanisms behind the various types of light-matter interactions at molecular length scales, where quantum effects come into play. Finally, we discuss the potential of these plasmonic-electronic hybrid systems across various future applications, including sensing, photocatalysis, molecular trapping and active control of molecular switches.
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Mennemanteuil MM, Buret M, Colas-des-Francs G, Bouhelier A. Optical rectification and thermal currents in optical tunneling gap antennas. NANOPHOTONICS 2022; 11:4197-4208. [PMID: 36118961 PMCID: PMC9412842 DOI: 10.1515/nanoph-2022-0278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
Electrically-contacted optical gap antennas are nanoscale interface devices enabling the transduction between photons and electrons. This new generation of device, usually constituted of metal elements (e.g. gold), captures visible to near infrared electromagnetic radiation and rectifies the incident energy in a direct-current (DC) electrical signal. However, light absorption by the metal may lead to additional thermal effects which need to be taken into account to understand the complete photo-response of the devices. The purpose of this communication is to discriminate the contribution of laser-induced thermo-electric effects in the photo-assisted electronic transport. We show case our analysis with the help of electromigrated devices.
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Affiliation(s)
- Marie Maxime Mennemanteuil
- Laboratoire Interdisciplinaire Carnot de Bourgogne CNRS UMR 6303, Université de Bourgogne Franche-Comté, 21000Dijon, France
| | - Mickaël Buret
- Laboratoire Interdisciplinaire Carnot de Bourgogne CNRS UMR 6303, Université de Bourgogne Franche-Comté, 21000Dijon, France
| | - Gérard Colas-des-Francs
- Laboratoire Interdisciplinaire Carnot de Bourgogne CNRS UMR 6303, Université de Bourgogne Franche-Comté, 21000Dijon, France
| | - Alexandre Bouhelier
- Laboratoire Interdisciplinaire Carnot de Bourgogne CNRS UMR 6303, Université de Bourgogne Franche-Comté, 21000Dijon, France
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6
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Joshi PB, Wilson AJ. Plasmonically enhanced electrochemistry boosted by nonaqueous solvent. J Chem Phys 2022; 156:241101. [DOI: 10.1063/5.0094694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Plasmon excitation of metal electrodes is known to enhance important energy related electrochemical transformations in aqueous media. However, the low solubility of nonpolar gases and molecular reagents involved in many energy conversion reactions limits the number of products formed per unit time in aqueous media. In this Communication, we use linear sweep voltammetry to measure how electrochemical H2O reduction in a nonaqueous solvent, acetonitrile, is enhanced by excitation of a plasmonic electrode. Plasmonically excited electrochemically roughened Au electrodes are found to produce photopotentials as large as 175 mV, which can be harnessed to lower the applied electrical bias required to drive the formation of H2. As the solvent polarity increases, by an increase in the concentration of H2O, the measured photopotential rapidly drops off to ∼50 mV. We propose a mechanism by which an increase in the H2O concentration increasingly stabilizes the photocharged plasmonic electrode, lowering the photopotential available to assist in the electrochemical reaction. Our study demonstrates that solvent polarity is an essential experimental parameter to optimize plasmonic enhancement in electrochemistry.
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Affiliation(s)
- Padmanabh B. Joshi
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA
| | - Andrew J. Wilson
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA
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Kos D, Assumpcao DR, Guo C, Baumberg JJ. Quantum Tunneling Induced Optical Rectification and Plasmon-Enhanced Photocurrent in Nanocavity Molecular Junctions. ACS NANO 2021; 15:14535-14543. [PMID: 34436876 DOI: 10.1021/acsnano.1c04100] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Molecular junctions offer the opportunity for downscaling optoelectronic devices. Separating two electrodes with a single layer of molecules accesses the quantum-tunneling regime at low voltages (<1 V), where tunneling currents become highly sensitive to local nanometer-scale geometric features of the electrodes. These features generate asymmetries in the electrical response of the junction which combine with the incident oscillating optical fields to produce optical rectification and photocurrents. Maximizing photocurrents requires accurate control of the overall junction geometry and a large confined optical field in the optimal location. Plasmonic nanostructures such as metallic nanoparticles are prime candidates for this application, because their size and shape dictate a consistent junction geometry while strongly enhancing the optical field from incident light. Here we demonstrate a robust lithography-free molecular optoelectronic device geometry, where a metallic nanoparticle on a self-assembled molecular monolayer is sandwiched between planar bottom and semitransparent top electrodes, to create molecular junctions with reproducible morphology and electrical response. The well-defined geometry enables predictable and intense plasmonic localization, which we show creates optical-frequency voltages ∼ 30 mV in the molecular junction from 100 μW incident light, generating photocurrent by optical rectification (>10 μA/W) from only a few hundred molecules. Quantitative agreement is thus obtained between DC- and optical-frequency quantum-tunneling currents, predicted by a simple analytic equation. By measuring the degree of junction asymmetry for different molecular monolayers, we find that molecules with a large DC rectification ratio also boost zero-bias electrical asymmetry, making them good candidates for sensing and energy harvesting applications in combination with plasmonic nanomaterials.
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Affiliation(s)
- Dean Kos
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Daniel R Assumpcao
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Chenyang Guo
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Jeremy J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thompson Avenue, Cambridge CB3 0HE, United Kingdom
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Ou W, Zhou B, Shen J, Zhao C, Li YY, Lu J. Plasmonic metal nanostructures: concepts, challenges and opportunities in photo-mediated chemical transformations. iScience 2021; 24:101982. [PMID: 33521596 PMCID: PMC7820137 DOI: 10.1016/j.isci.2020.101982] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Plasmonic metal nanostructures (PMNs) are characterized by the plasmon oscillation of conduction band electron in response to external radiation, enabling strong light absorption and scattering capacities and near-field amplification. Owing to these enhanced light-matter interactions, PMNs have garnered extensive research interest in the past decades. Notably, a growingly large number of reports show that the energetics and kinetics of chemical transformations on PMNs can be modified upon photoexcitation of their plasmons, giving rise to a new paradigm of manipulating the reaction rate and selectivity of chemical reactions. On the other hand, there is urgent need to achieve clear understanding of the mechanism underlying the photo-mediated chemical transformations on PMNs for unleashing their full potential in converting solar energy to chemicals. In this perspective, we review current fundamental concepts of photo-mediated chemical transformations executed at PMNs. Three pivotal mechanistic questions, i.e., thermal and nonthermal effects, direct and indirect charge transfer processes, and the specific impacts of plasmon-induced potentials, are explored based on recent studies. We highlight the critical aspects in which major advancements should be made to facilitate the rational design and optimization of photo-mediated chemical transformations on PMNs in the future.
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Affiliation(s)
- Weihui Ou
- Centre for Advanced Structural Materials, City University of Hong Kong Shenzhen Research Institute, Greater Bay Joint Division, Shenyang National Laboratory for Materials Science, Shenzhen 518057, China
- Hong Kong Branch of National Precious Metals Material Engineering Research Center, City University of Hong Kong, Hong Kong, China
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
| | - Binbin Zhou
- Centre for Advanced Structural Materials, City University of Hong Kong Shenzhen Research Institute, Greater Bay Joint Division, Shenyang National Laboratory for Materials Science, Shenzhen 518057, China
- Hong Kong Branch of National Precious Metals Material Engineering Research Center, City University of Hong Kong, Hong Kong, China
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
| | - Junda Shen
- Hong Kong Branch of National Precious Metals Material Engineering Research Center, City University of Hong Kong, Hong Kong, China
- Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong, China
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China
| | - Chenghao Zhao
- Hong Kong Branch of National Precious Metals Material Engineering Research Center, City University of Hong Kong, Hong Kong, China
- Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong, China
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China
| | - Yang Yang Li
- Centre for Advanced Structural Materials, City University of Hong Kong Shenzhen Research Institute, Greater Bay Joint Division, Shenyang National Laboratory for Materials Science, Shenzhen 518057, China
- Hong Kong Branch of National Precious Metals Material Engineering Research Center, City University of Hong Kong, Hong Kong, China
- Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong, China
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China
| | - Jian Lu
- Centre for Advanced Structural Materials, City University of Hong Kong Shenzhen Research Institute, Greater Bay Joint Division, Shenyang National Laboratory for Materials Science, Shenzhen 518057, China
- Hong Kong Branch of National Precious Metals Material Engineering Research Center, City University of Hong Kong, Hong Kong, China
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
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Zhu Y, Natelson D, Cui L. Probing energy dissipation in molecular-scale junctions via surface enhanced Raman spectroscopy: vibrational pumping and hot carrier enhanced light emission. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:134001. [PMID: 33429369 DOI: 10.1088/1361-648x/abda7b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
Experimentally resolving the microscopic energy dissipation and redistribution pathways in a molecular-scale junction, the smallest possible nanoelectronic device, is of great current interest. Here we report measurements of the vibrational pumping and light emission processes in current-carrying molecular junctions using surface enhanced Raman spectroscopy. We show that the heating of vibrational modes exhibits distinct features when the molecular junctions are driven by electrical bias or optical power. We further discuss the hot carrier origin of the broadband continuum emission observed in the Raman scattering spectrum.
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Affiliation(s)
- Yunxuan Zhu
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, United States of America
| | - Douglas Natelson
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, United States of America
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, United States of America
- Department of Materials Science and Nanoengineering, Rice University, Houston, TX 77005, United States of America
| | - Longji Cui
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, United States of America
- Paul M Rady Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309, United States of America
- Materials Science and Engineering Program, University of Colorado, Boulder, CO 80309, United States of America
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10
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Abstract
ConspectusPlasmonic nanostructures have garnered widescale scientific interest because of their strong light-matter interactions and the tunability of their absorption across the solar spectrum. At the heart of their superlative interaction with light is the resonant excitation of a collective oscillation of electrons in the nanostructure by the incident electromagnetic field. These resonant oscillations are known as localized surface plasmon resonances (LSPRs). In recent years, the community has uncovered intriguing photochemical attributes of noble metal nanostructures arising from their LSPRs. Chemical reactions that are otherwise unfavorable or sluggish in the dark are induced on the nanostructure surface upon photoexcitation of LSPRs. This phenomenon has led to the birth of plasmonic catalysis. The rates of a variety of kinetically challenging reactions are enhanced by plasmon-excited nanostructures. While the potential utility for solar energy harvesting and chemical production is clear, there is a natural curiosity about the precise origin(s) of plasmonic catalysis. One explanation is that the reactions are facilitated by the action of the intensely concentrated and confined electric fields generated on the nanostructure upon LSPR excitation. Another mechanism of activation involves hot carriers transiently produced in the metal nanostructure by damping of LSPRs.In this Account, we visit a phenomenon that has received less attention but has a key role to play in plasmonic catalysis and chemistry. Under common chemical scenarios, plasmonic excitation induces a potential or a voltage on a nanoparticle. This photopotential modifies the energetics of a chemical reaction on noble metal nanoparticles. In a range of cases studied by our laboratory and others, light-induced potentials underlie the plasmonic enhancement of reaction kinetics. The photopotential model does not replace other known mechanisms, but it complements them. There are multiple ways in which an electrostatic photopotential is produced by LSPR excitation, such as optical rectification, but one that is most relevant in chemical media is asymmetric charge transfer to solution-phase acceptors. Electrons and holes produced in a nanostructure by damping of LSPRs are not removed at the same rate. As a result, the slower carrier accumulates on the nanostructure, and a steady-state charge is built up on the nanostructure, leading to a photopotential. Potentials of up to a few hundred millivolts have been measured by our laboratory and others. A photocharged nanoparticle is a source of carriers of a higher potential than an uncharged one. As a result, redox chemical reactions on noble metal nanoparticles exhibit lower activation barriers under photoexcitation. In electrochemical reactions on noble metal nanoparticles, the photopotential supplements the applied potential. In a diverse set of reactions, the photopotential model explains the photoenhancement of rates as well as the trends as a function of light intensity and photon energy. With further gains, light-induced potentials may be used as a knob for controlling the activities and selectivities of noble metal nanoparticle catalysts.
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Affiliation(s)
- Andrew J. Wilson
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Prashant K. Jain
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Department of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Materials Research Lab, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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Lu X, Sun L, Jiang P, Bao X. Progress of Photodetectors Based on the Photothermoelectric Effect. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1902044. [PMID: 31483546 DOI: 10.1002/adma.201902044] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 07/06/2019] [Indexed: 06/10/2023]
Abstract
High-performance uncooled photodetectors operating in the long-wavelength infrared and terahertz regimes are highly demanded in the military and civilian fields. Photothermoelectric (PTE) detectors, which combine photothermal and thermoelectric conversion processes, can realize ultra-broadband photodetection without the requirement of a cooling unit and external bias. In the last few decades, the responsivity and speed of PTE-based photodetectors have made impressive progress with the discovery of novel thermoelectric materials and the development of nanophotonics. In particular, by introducing hot-carrier transport into low-dimensional material-based PTE detectors, the response time has been successfully pushed down to the picosecond level. Furthermore, with the assistance of surface plasmon, antenna, and phonon absorption, the responsivity of PTE detectors can be significantly enhanced. Beyond the photodetection, PTE effect can also be utilized to probe exotic physical phenomena in spintronics and valleytronics. Herein, recent advances in PTE detectors are summarized, and some potential strategies to further improve the performance are proposed.
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Affiliation(s)
- Xiaowei Lu
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China
| | - Lin Sun
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China
| | - Peng Jiang
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China
| | - Xinhe Bao
- State Key Laboratory of Catalysis, CAS Center for Excellence in Nanoscience, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China
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Dai W, Liang Y, Yang M, Schrecongost D, Gajurel P, Lee H, Lee JW, Chen J, Eom CB, Cen C. Large and Reconfigurable Infrared Photothermoelectric Effect at Oxide Interfaces. NANO LETTERS 2019; 19:7149-7154. [PMID: 31525937 DOI: 10.1021/acs.nanolett.9b02712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
To maximize the photovoltaic efficiency, it is highly desirable to enable the electricity conversion from low energy photons and to extract the excessive energy from hot carriers. Here we report a large photovoltage generation at the LaAlO3/SrTiO3 interfaces from infrared photons with energies far below the oxide bandgaps. This effect is a result of the photoexcitation of hot carriers in metasurface electrical contacts and the subsequent thermoelectric charge separations by the interfacial two-dimensional electron gas (2DEG). Reaching a room-temperature responsivity of 4.4 V/W, such light-to-charge conversion can be spatially controlled and reconfigured through the patterning of 2DEG using conducting atomic force microscope. Compatible for broadband applications, our results demonstrate a new path toward efficient and programmable light sensing using oxide-based low-dimensional electron systems.
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Affiliation(s)
- Weitao Dai
- Department of Physics and Astronomy , West Virginia University , Morgantown , West Virginia 26506 , United States
| | - Yi Liang
- Department of Physics and Astronomy , West Virginia University , Morgantown , West Virginia 26506 , United States
- Guangxi Key Lab for Relativistic Astrophysics, Center on Nanoenergy Research, School of Physical Science and Technology , Guangxi University, Nanning , Guangxi 530004 , China
| | - Ming Yang
- Department of Physics and Astronomy , West Virginia University , Morgantown , West Virginia 26506 , United States
| | - Dustin Schrecongost
- Department of Physics and Astronomy , West Virginia University , Morgantown , West Virginia 26506 , United States
| | - Prakash Gajurel
- Department of Physics and Astronomy , West Virginia University , Morgantown , West Virginia 26506 , United States
| | - Hyungwoo Lee
- Department of Material Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Jung-Woo Lee
- Department of Material Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Jun Chen
- Department of Electrical and Computer Engineering and Peterson Institute of NanoScience and Engineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Chang-Beom Eom
- Department of Material Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Cheng Cen
- Department of Physics and Astronomy , West Virginia University , Morgantown , West Virginia 26506 , United States
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Wang X, Evans CI, Natelson D. Photothermoelectric Detection of Gold Oxide Nonthermal Decomposition. NANO LETTERS 2018; 18:6557-6562. [PMID: 30226779 DOI: 10.1021/acs.nanolett.8b03153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A thin coating of gold oxide, metastable at room temperature, can be formed by placing gold in a strongly oxidizing environment such as an oxygen plasma. We report scanning photovoltage measurements of lithographically defined gold nanowires subsequent to oxygen plasma exposure. Photovoltages are detected during the first optical scan of the devices that are several times larger than those mapped on subsequent scans. The first-scan enhanced photovoltage correlates with a reduction of the electrical resistance of the nanostructure back to preoxygen-exposure levels. Repeating oxygen plasma exposure "reinitializes" the devices. These combined photovoltage and transport measurements imply that the enhanced photovoltage results from the photothermoelectric response of a junction between Au and oxidized Au, with an optically driven decomposition of the oxide. Comparisons with the known temperature-dependent kinetics of AuOx decomposition suggest that the light-driven decomposition is not a purely thermal effect. These experiments demonstrate that combined optical and electronic measurements can provide a window on surface-sensitive photochemical processes.
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Affiliation(s)
- Xifan Wang
- Department of Materials Science and NanoEngineering , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
| | - Charlotte I Evans
- Department of Physics and Astronomy , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
| | - Douglas Natelson
- Department of Materials Science and NanoEngineering , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
- Department of Physics and Astronomy , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
- Department of Electrical and Computer Engineering , Rice University , 6100 Main Street , Houston , Texas 77005 , United States
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Chatterjee A, Bai T, Edler F, Tegenkamp C, Weide-Zaage K, Pfnür H. Electromigration and morphological changes in Ag nanostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:084002. [PMID: 29336347 DOI: 10.1088/1361-648x/aaa80a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electromigration (EM) as a structuring tool was investigated in Ag nanowires (width 300 nm, thickness 25 nm) and partly in notched and bow-tie Ag structures on a Si(1 0 0) substrate in ultra-high vacuum using a four-tip scanning tunneling microscope in combination with a scanning electron microscope. From simulations of Ag nanowires we got estimates of temperature profiles, current density profiles, EM and thermal migration (TM) mass flux distributions within the nanowire induced by critical current densities of 108 A cm-2. At room temperature, the electron wind force at these current densities by far dominates over thermal diffusion, and is responsible for formation of voids at the cathode and hillocks at the anode side. For current densities that exceed the critical current densities necessary for EM, a new type of wire-like structure formation was found both at room temperature and at 100 K for notched and bow-tie structures. This suggests that the simultaneous action of EM and TM is structure forming, but with a very small influence of TM at low temperature.
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Affiliation(s)
- A Chatterjee
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany. Laboratorium für Nano und Quantenengineering (LNQE), Leibniz Universität Hannover, Schneiderberg 39, 30167 Hannover, Germany
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Zolotavin P, Evans CI, Natelson D. Substantial local variation of the Seebeck coefficient in gold nanowires. NANOSCALE 2017. [PMID: 28650059 DOI: 10.1039/c7nr02678a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Nanoscale structuring holds promise to improve the thermoelectric properties of materials for energy conversion and photodetection. We report a study of the spatial distribution of the photothermoelectric voltage in thin-film nanowire devices fabricated from a single metal. A focused laser beam is used to locally heat the metal nanostructure via a combination of direct absorption and excitation of a plasmon resonance in Au devices. As seen previously, in nanowires shorter than the spot size of the laser, we observe a thermoelectric voltage distribution that is consistent with the local Seebeck coefficient being spatially dependent on the width of the nanostructure. In longer structures, we observe extreme variability of the net thermoelectric voltage as the laser spot is scanned along the length of the nanowire. The sign and magnitude of the thermoelectric voltage is sensitive to the structural defects, metal grain structure, and surface passivation of the nanowire. This finding opens the possibility of improved local control of the thermoelectric properties at the nanoscale.
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Affiliation(s)
- Pavlo Zolotavin
- Department of Physics and Astronomy, Rice University, 6100 Main St, Houston, Texas 77005, USA.
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