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Sabour B, Wagner RJV, Krüger BC, Kandratsenka A, Wodtke AM, Schäfer T, Park GB. Vibrationally Mode-Specific Molecular Energy Transfer to Surface Electrons in Metastable Formaldehyde Scattering from Cesium-Covered Au(111). J Phys Chem A 2024; 128:4976-4983. [PMID: 38850250 PMCID: PMC11215783 DOI: 10.1021/acs.jpca.4c02184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/20/2024] [Accepted: 05/20/2024] [Indexed: 06/10/2024]
Abstract
Nonadiabatic interaction of adsorbate nuclear motion with the continuum of electronic states is known to affect the dynamics of chemical reactions at metal surfaces. A large body of work has probed the fundamental mechanisms of such interactions for atomic and diatomic molecules at surfaces. In polyatomic molecules, the possibility of mode-specific damping of vibrational motion due to the effects of electronic friction raises the question of whether such interactions could profoundly affect the outcome of chemistry at surfaces by selectively removing energy from a particular intramolecular adsorbate mode. However, to date, there have not been any fundamental experiments demonstrating nonadiabatic electron-vibration coupling in a polyatomic molecule at a surface. In this work, we scatter excited metastable formaldehyde and formaldehyde-d2 from a low work function surface and detect ejected exoelectrons that accompany molecular relaxation. The exoelectron ejection efficiency exhibits a strong dependence on the vibrational mode that is excited: out-of-plane bending excitation (ν4) leads to significantly more exoelectrons than does CO stretching excitation (ν2). The results provide clear evidence for mode-specific energy transfer from vibration to surface electrons.
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Affiliation(s)
- Behrouz Sabour
- Department
of Chemistry and Biochemistry, Texas Tech
University, Box 41061 Lubbock, Texas 79409-1061, United States
| | - Roman J. V. Wagner
- Max-Planck-Institut
für Multidisziplinäre Naturwissenschaften, Am Faßberg 11, Göttingen 37077, Germany
- Georg-August-Universität
Göttingen, Institut für physikalische Chemie, Tammanstr. 6, Göttingen 37077, Germany
| | - Bastian C. Krüger
- Max-Planck-Institut
für Multidisziplinäre Naturwissenschaften, Am Faßberg 11, Göttingen 37077, Germany
- Georg-August-Universität
Göttingen, Institut für physikalische Chemie, Tammanstr. 6, Göttingen 37077, Germany
| | - Alexander Kandratsenka
- Max-Planck-Institut
für Multidisziplinäre Naturwissenschaften, Am Faßberg 11, Göttingen 37077, Germany
- Georg-August-Universität
Göttingen, Institut für physikalische Chemie, Tammanstr. 6, Göttingen 37077, Germany
| | - Alec M. Wodtke
- Max-Planck-Institut
für Multidisziplinäre Naturwissenschaften, Am Faßberg 11, Göttingen 37077, Germany
- Georg-August-Universität
Göttingen, Institut für physikalische Chemie, Tammanstr. 6, Göttingen 37077, Germany
- International
Center for Advanced Studies of Energy Conversion, University of Göttingen, Göttingen 37077, Germany
| | - Tim Schäfer
- Max-Planck-Institut
für Multidisziplinäre Naturwissenschaften, Am Faßberg 11, Göttingen 37077, Germany
- Georg-August-Universität
Göttingen, Institut für physikalische Chemie, Tammanstr. 6, Göttingen 37077, Germany
| | - G. Barratt Park
- Department
of Chemistry and Biochemistry, Texas Tech
University, Box 41061 Lubbock, Texas 79409-1061, United States
- Max-Planck-Institut
für Multidisziplinäre Naturwissenschaften, Am Faßberg 11, Göttingen 37077, Germany
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2
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Rahinov I, Kandratsenka A, Schäfer T, Shirhatti P, Golibrzuch K, Wodtke AM. Vibrational energy transfer in collisions of molecules with metal surfaces. Phys Chem Chem Phys 2024; 26:15090-15114. [PMID: 38757203 PMCID: PMC11135613 DOI: 10.1039/d4cp00957f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 04/27/2024] [Indexed: 05/18/2024]
Abstract
The Born-Oppenheimer approximation (BOA), which serves as the basis for our understanding of chemical bonding, reactivity and dynamics, is routinely violated for vibrationally inelastic scattering of molecules at metal surfaces. The title-field therefore represents a fascinating challenge to our conventional wisdom calling for new concepts that involve explicit electron dynamics occurring in concert with nuclear motion. Here, we review progress made in this field over the last decade, which has witnessed dramatic advances in experimental methods, thereby providing a much more extensive set of diverse observations than has ever before been available. We first review the experimental methods used in this field and then provide a systematic tour of the vast array of observations that are currently available. We show how these observations - taken together and without reference to computational simulations - lead us to a simple and intuitive picture of BOA failure in molecular dynamics at metal surfaces, one where electron transfer between the molecule and the metal plays a preeminent role. We also review recent progress made in the theory of electron transfer mediated BOA failure in molecule-surface interactions, describing the most important methods and their ability to reproduce experimental observation. Finally, we outline future directions for research and important unanswered questions.
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Affiliation(s)
- Igor Rahinov
- Department of Natural Sciences, The Open University of Israel, 4353701 Raanana, Israel.
| | - Alexander Kandratsenka
- Department of Dynamics at Surfaces, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Goettingen, Germany.
| | - Tim Schäfer
- Institute for Physical Chemistry, Georg-August University of Goettingen, Tammannstraße 6, 37077 Goettingen, Germany
| | - Pranav Shirhatti
- Tata Institute of Fundamental Research Hyderabad, 36/P Gopanpally, Hyderabad 500046, Telangana, India
| | - Kai Golibrzuch
- Department of Dynamics at Surfaces, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Goettingen, Germany.
| | - Alec M Wodtke
- Department of Dynamics at Surfaces, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Goettingen, Germany.
- Institute for Physical Chemistry, Georg-August University of Goettingen, Tammannstraße 6, 37077 Goettingen, Germany
- International Center for Advanced Studies of Energy Conversion, Georg-August University of Goettingen, Tammannstraße 6, 37077 Goettingen, Germany
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3
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Hati S, Yang X, Gupta P, Muhoberac BB, Pu J, Zhang J, Sardar R. Hybrid Metal-Ligand Interfacial Dipole Engineering of Functional Plasmonic Nanostructures for Extraordinary Responses of Optoelectronic Properties. ACS NANO 2023; 17:17499-17515. [PMID: 37579222 DOI: 10.1021/acsnano.3c06047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
Programmable manipulation of inorganic-organic interfacial electronic properties of ligand-functionalized plasmonic nanoparticles (NPs) is the key parameter dictating their applications such as catalysis, photovoltaics, and biosensing. Here we report the localized surface plasmon resonance (LSPR) properties of gold triangular nanoprisms (Au TNPs) in solid state that are functionalized with dipolar, conjugated ligands. A library of thiocinnamate ligands with varying surface dipole moments were used to functionalize TNPs, which results in ∼150 nm reversible tunability of LSPR peak wavelength with significant peak broadening (∼230 meV). The highly adjustable chemical system of thiocinnamate ligands is capable of shifting the Au work function down to 2.4 eV versus vacuum, i.e., ∼2.9 eV lower than a clean Au (111) surface, and this work function can be modulated up to 3.3 eV, the largest value reported to date through the formation of organothiolate SAMs on Au. Interestingly, the magnitude of plasmonic responses and work function modulation is NP shape dependent. By combining first-principles calculations and experiments, we have established the mechanism of direct wave function delocalization of electrons residing near the Fermi level into hybrid electronic states that are mostly dictated by the inorganic-organic interfacial dipole moments. We determine that both interfacial dipole and hybrid electronic states, and vinyl conjugation together are the key to achieving such extraordinary changes in the optoelectronic properties of ligand-functionalized, plasmonic NPs. The present study provides a quantitative relationship describing how specifically constructed organic ligands can be used to control the interfacial properties of NPs and thus the plasmonic and electronic responses of these functional plasmonics for a wide range of plasmon-driven applications.
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Affiliation(s)
- Sumon Hati
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Xuehui Yang
- Department of Mechanical and Energy engineering, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Prashant Gupta
- Department of Mechanical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Barry B Muhoberac
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Jingzhi Pu
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Jing Zhang
- Department of Mechanical and Energy engineering, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Rajesh Sardar
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
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4
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Bolli E, Mezzi A, Kaciulis S, Serpente V, Bellucci A, Trucchi DM. Temperature dependence of the work function in barium fluoride ultra‐thin films on semiconductors for hybrid thermionic converters studied by ultraviolet photoelectron spectroscopy. SURF INTERFACE ANAL 2022. [DOI: 10.1002/sia.7182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Eleonora Bolli
- Department of Industrial Engineering University of Rome “Tor Vergata” Rome Italy
- Institute of Structure of Matter, DiaTHEMA Lab ISM‐CNR Rome Italy
| | - Alessio Mezzi
- Institute for the Study of Nanostructured Materials ISMN‐CNR Rome Italy
| | - Saulius Kaciulis
- Institute for the Study of Nanostructured Materials ISMN‐CNR Rome Italy
| | - Valerio Serpente
- Institute of Structure of Matter, DiaTHEMA Lab ISM‐CNR Rome Italy
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5
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Auerbach DJ, Tully JC, Wodtke AM. Chemical dynamics from the gas‐phase to surfaces. ACTA ACUST UNITED AC 2021. [DOI: 10.1002/ntls.10005] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Daniel J. Auerbach
- Institut für physikalische Chemie Georg‐August Universität Göttingen Göttingen Germany
- Abteilung für Dynamik an Oberflächen Max‐Planck‐Institut für biophysikalische Chemie Göttingen Germany
| | - John C. Tully
- Department of Chemistry Yale University New Haven Connecticut USA
| | - Alec M. Wodtke
- Institut für physikalische Chemie Georg‐August Universität Göttingen Göttingen Germany
- Abteilung für Dynamik an Oberflächen Max‐Planck‐Institut für biophysikalische Chemie Göttingen Germany
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6
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Bellucci A, Girolami M, Mastellone M, Orlando S, Polini R, Santagata A, Serpente V, Valentini V, Trucchi DM. Novel concepts and nanostructured materials for thermionic-based solar and thermal energy converters. NANOTECHNOLOGY 2021; 32:024002. [PMID: 32957094 DOI: 10.1088/1361-6528/abba57] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Thermal and concentrated solar solid-state converters are devices with no moving parts, corresponding to long lifetimes, limited necessity of maintenance, and scalability. Among the solid-state converters, the thermionic-based devices are attracting an increasing interest in the specific growing sector of energy conversion performed at high-temperature. During the last 10 years, hybrid thermionic-based concepts, conceived to cover operating temperatures up to 2000 °C, have been intensively developed. In this review, the thermionic-thermoelectric, photon-enhanced thermionic emission, thermionic-photovoltaic energy converters are extensively discussed. The design and development processes as well as the tailoring of the properties of nanostructured materials performed by the authors are comprehensively described and compared with the advances achieved by the international scientific community.
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Affiliation(s)
- A Bellucci
- Istituto di Struttura della Materia-CNR (ISM-CNR), DiaTHEMA Lab, Monterotondo Scalo (RM), Italy
| | - M Girolami
- Istituto di Struttura della Materia-CNR (ISM-CNR), DiaTHEMA Lab, Monterotondo Scalo (RM), Italy
| | - M Mastellone
- Istituto di Struttura della Materia-CNR (ISM-CNR), DiaTHEMA Lab, Monterotondo Scalo (RM), Italy
- Dipartimento di Scienze di Base ed Applicate per l'Ingegneria, Univ. of Rome 'La Sapienza', Rome, Italy
| | - S Orlando
- Istituto di Struttura della Materia-CNR (ISM-CNR), FemtoLab, Tito Scalo (PZ), Italy
| | - R Polini
- Istituto di Struttura della Materia-CNR (ISM-CNR), DiaTHEMA Lab, Monterotondo Scalo (RM), Italy
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma 'Tor Vergata', Rome, Italy
| | - A Santagata
- Istituto di Struttura della Materia-CNR (ISM-CNR), FemtoLab, Tito Scalo (PZ), Italy
| | - V Serpente
- Istituto di Struttura della Materia-CNR (ISM-CNR), DiaTHEMA Lab, Monterotondo Scalo (RM), Italy
| | - V Valentini
- Istituto di Struttura della Materia-CNR (ISM-CNR), DiaTHEMA Lab, Monterotondo Scalo (RM), Italy
| | - D M Trucchi
- Istituto di Struttura della Materia-CNR (ISM-CNR), DiaTHEMA Lab, Monterotondo Scalo (RM), Italy
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7
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Halliday MTE, Hess WP, Shluger AL. A mechanism of Cu work function reduction in CsBr/Cu photocathodes. Phys Chem Chem Phys 2016; 18:7427-34. [PMID: 26899524 DOI: 10.1039/c5cp07694c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Thin films of CsBr deposited on Cu(100) have been proposed as next-generation photocathode materials for applications in particle accelerators and free-electron lasers. However, the mechanisms underlying an improved photocathode performance as well as their long-term stability remain poorly understood. We present Density Functional Theory (DFT) calculations of the work function reduction following the application of CsBr thin film coatings to Cu photocathodes. The effects of both flat and rough interface and van der Waals forces are examined. Calculations suggest that CsBr films can reduce the Cu(100) work function by about 1.5 eV, which would explain the observed increase in quantum efficiency (QE) of coated vs. uncoated photocathodes. A model explaining the experimentally observed laser activation of photocathodes is provided whereby the photo-induced creation of Br vacancies and Cs-Br di-vacancies and their subsequent diffusion to the Cu/CsBr interface lead to a further increase in QE after a period of laser irradiation.
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Affiliation(s)
- M T E Halliday
- Department of Physics and Astronomy and the London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK.
| | - W P Hess
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA
| | - A L Shluger
- Department of Physics and Astronomy and the London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK.
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8
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Narasimha KT, Ge C, Fabbri JD, Clay W, Tkachenko BA, Fokin AA, Schreiner PR, Dahl JE, Carlson RMK, Shen ZX, Melosh NA. Ultralow effective work function surfaces using diamondoid monolayers. NATURE NANOTECHNOLOGY 2016; 11:267-272. [PMID: 26641529 DOI: 10.1038/nnano.2015.277] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 10/26/2015] [Indexed: 06/05/2023]
Abstract
Electron emission is critical for a host of modern fabrication and analysis applications including mass spectrometry, electron imaging and nanopatterning. Here, we report that monolayers of diamondoids effectively confer dramatically enhanced field emission properties to metal surfaces. We attribute the improved emission to a significant reduction of the work function rather than a geometric enhancement. This effect depends on the particular diamondoid isomer, with [121]tetramantane-2-thiol reducing gold's work function from ∼ 5.1 eV to 1.60 ± 0.3 eV, corresponding to an increase in current by a factor of over 13,000. This reduction in work function is the largest reported for any organic species and also the largest for any air-stable compound. This effect was not observed for sp(3)-hybridized alkanes, nor for smaller diamondoid molecules. The magnitude of the enhancement, molecule specificity and elimination of gold metal rearrangement precludes geometric factors as the dominant contribution. Instead, we attribute this effect to the stable radical cation of diamondoids. Our computed enhancement due to a positively charged radical cation was in agreement with the measured work functions to within ± 0.3 eV, suggesting a new paradigm for low-work-function coatings based on the design of nanoparticles with stable radical cations.
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Affiliation(s)
- Karthik Thimmavajjula Narasimha
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Chenhao Ge
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Jason D Fabbri
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - William Clay
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Boryslav A Tkachenko
- Institute of Organic Chemistry, Justus-Liebig University, Giessen, Heinrich-Buff-Ring 17, Giessen 35392, Germany
| | - Andrey A Fokin
- Institute of Organic Chemistry, Justus-Liebig University, Giessen, Heinrich-Buff-Ring 17, Giessen 35392, Germany
- Kiev Polytechnic Institute, pr. Pobedy 37, Kiev 03056, Ukraine
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus-Liebig University, Giessen, Heinrich-Buff-Ring 17, Giessen 35392, Germany
| | - Jeremy E Dahl
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Robert M K Carlson
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Z X Shen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Nicholas A Melosh
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
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9
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Krüger BC, Meyer S, Kandratsenka A, Wodtke AM, Schäfer T. Vibrational Inelasticity of Highly Vibrationally Excited NO on Ag(111). J Phys Chem Lett 2016; 7:441-6. [PMID: 26760437 DOI: 10.1021/acs.jpclett.5b02448] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Multiquantum relaxation of highly vibrationally excited nitric oxide on noble metals has become one of the best studied examples of the Born-Oppenheimer approximation's failure to describe molecular interactions at metal surfaces. When first reported, relaxation of highly vibrationally excited NO occurring in collisions with Au(111) surfaces exhibited the largest vibrational inelasticity seen in molecule-surface collisions, and no system has been found to date exhibiting a greater vibrational inelasticity. In this work, we compare the relaxation of NO(v = 11) in scattering events on Ag(111) to that on Au(111). The relaxation probability and the average vibrational energy loss are much higher when scattering from Ag(111). We discuss possible reasons for this remarkable phenomenon, which may be related to the dissociation of NO, possible on Ag(111) at lower energy compared with Au(111).
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Affiliation(s)
- Bastian C Krüger
- Institute of Physical Chemistry, Georg-August University of Göttingen , Tammannstraße 6, 37077 Göttingen, Germany
| | - Sven Meyer
- Institute of Physical Chemistry, Georg-August University of Göttingen , Tammannstraße 6, 37077 Göttingen, Germany
| | - Alexander Kandratsenka
- Institute of Physical Chemistry, Georg-August University of Göttingen , Tammannstraße 6, 37077 Göttingen, Germany
- Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry , Am Faßberg 11, 37077 Göttingen, Germany
| | - Alec M Wodtke
- Institute of Physical Chemistry, Georg-August University of Göttingen , Tammannstraße 6, 37077 Göttingen, Germany
- Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry , Am Faßberg 11, 37077 Göttingen, Germany
- International Center for Advanced Studies of Energy Conversion, University of Göttingen , 37077 Göttingen, Germany
| | - Tim Schäfer
- Institute of Physical Chemistry, Georg-August University of Göttingen , Tammannstraße 6, 37077 Göttingen, Germany
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10
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Wodtke AM. Electronically non-adiabatic influences in surface chemistry and dynamics. Chem Soc Rev 2016; 45:3641-57. [DOI: 10.1039/c6cs00078a] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electronically nonadiabatic interactions between molecules and metal surfaces are now well known. But evidence that such interactions influence reaction rates is still scarce. This paper reviews research related to this topic and proposes pathways forward.
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Affiliation(s)
- Alec M. Wodtke
- Institute for Physical Chemistry
- Georg-August University of Göttingen
- Germany
- Max Planck Institute for Biophysical Chemistry
- Göttingen
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11
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Axnanda S, Scheele M, Crumlin E, Mao B, Chang R, Rani S, Faiz M, Wang S, Alivisatos AP, Liu Z. Direct work function measurement by gas phase photoelectron spectroscopy and its application on PbS nanoparticles. NANO LETTERS 2013; 13:6176-6182. [PMID: 24175587 DOI: 10.1021/nl403524a] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Work function is a fundamental property of a material's surface. It is playing an ever more important role in engineering new energy materials and efficient energy devices, especially in the field of photovoltaic devices, catalysis, semiconductor heterojunctions, nanotechnology, and electrochemistry. Using ambient pressure X-ray photoelectron spectroscopy (APXPS), we have measured the binding energies of core level photoelectrons of Ar gas in the vicinity of several reference materials with known work functions (Au(111), Pt(111), graphite) and PbS nanoparticles. We demonstrate an unambiguously negative correlation between the work functions of reference samples and the binding energies of Ar 2p core level photoelectrons detected from the Ar gas near the sample surface region. Using this experimentally determined linear relationship between the surface work function and Ar gas core level photoelectron binding energy, we can measure the surface work function of different materials under different gas environments. To demonstrate the potential applications of this ambient pressure XPS technique in nanotechnology and solar energy research, we investigate the work functions of PbS nanoparticles with various capping ligands: methoxide, mercaptopropionic acid, and ethanedithiol. Significant Fermi level position changes are observed for PbS nanoparticles when the nanoparticle size and capping ligands are varied. The corresponding changes in the valence band maximum illustrate that an efficient quantum dot solar cell design has to take into account the electrochemical effect of the capping ligand as well.
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Affiliation(s)
- Stephanus Axnanda
- Advanced Light Source Division and ‡Material Science Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720
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12
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Vibrational Energy Transfer at Surfaces: The Importance of Non-Adiabatic Electronic Effects. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/978-3-642-32955-5_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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13
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LaRue JL, Schäfer T, Matsiev D, Velarde L, Nahler NH, Auerbach DJ, Wodtke AM. Electron kinetic energies from vibrationally promoted surface exoemission: evidence for a vibrational autodetachment mechanism. J Phys Chem A 2011; 115:14306-14. [PMID: 22112161 DOI: 10.1021/jp205868g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report kinetic energy distributions of exoelectrons produced by collisions of highly vibrationally excited NO molecules with a low work function Cs dosed Au(111) surface. These measurements show that energy dissipation pathways involving nonadiabatic conversion of vibrational energy to electronic energy can result in electronic excitation of more than 3 eV, consistent with the available vibrational energy. We measured the dependence of the electron energy distributions on the translational and vibrational energy of the incident NO and find a clear positive correlation between final electron kinetic energy and initial vibrational excitation and a weak but observable inverse dependence of electron kinetic energy on initial translational energy. These observations are consistent with a vibrational autodetachment mechanism, where an electron is transferred to NO near its outer vibrational turning point and ejected near its inner vibrational turning point. Within the context of this model, we estimate the NO-to-surface distance for electron transfer.
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Affiliation(s)
- Jerry L LaRue
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, United States
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14
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Wäckerlin C, Iacovita C, Chylarecka D, Fesser P, Jung TA, Ballav N. Assembly of 2D ionic layers by reaction of alkali halides with the organic electrophile 7,7,8,8-tetracyano-p-quinodimethane (TCNQ). Chem Commun (Camb) 2011; 47:9146-8. [PMID: 21750826 DOI: 10.1039/c1cc12519b] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sublimation of alkali halides (NaCl and LiCl) onto a pre-assembled hydrogen-bonded layer of TCNQ on Au(111) resulted in the formation of 2D ionic layers via a direct charge-transfer reaction without involvement of the substrate. The presented approach allows for the fabrication of different ionic layers, decoupled from the substrate and offering new, potentially interesting properties.
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Affiliation(s)
- Christian Wäckerlin
- Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen, Switzerland
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15
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LaRue J, Schäfer T, Matsiev D, Velarde L, Nahler NH, Auerbach DJ, Wodtke AM. Vibrationally promoted electron emission at a metal surface: electron kinetic energy distributions. Phys Chem Chem Phys 2011; 13:97-9. [DOI: 10.1039/c0cp01626h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Rahinov I, Cooper R, Matsiev D, Bartels C, Auerbach DJ, Wodtke AM. Quantifying the breakdown of the Born–Oppenheimer approximation in surface chemistry. Phys Chem Chem Phys 2011; 13:12680-92. [DOI: 10.1039/c1cp20356h] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Bartels C, Cooper R, Auerbach DJ, Wodtke AM. Energy transfer at metal surfaces: the need to go beyond the electronic friction picture. Chem Sci 2011. [DOI: 10.1039/c1sc00181g] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Nahler NH, White JD, LaRue J, Auerbach DJ, Wodtke AM. Inverse Velocity Dependence of Vibrationally Promoted Electron Emission from a Metal Surface. Science 2008; 321:1191-4. [DOI: 10.1126/science.1160040] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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