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Title: Hot Hole Collection and Photoelectrochemical CO 2 Reduction with Plasmonic Au/p-GaN Photocathodes

Abstract

Harvesting nonequilibrium hot carriers from plasmonic- metal nanostructures offers unique opportunities for driving photo- chemical reactions at the nanoscale. Despite numerous examples of hot electron-driven processes, the realization of plasmonic systems capable of harvesting hot holes from metal nanostructures has eluded the nascent field of plasmonic photocatalysis. In this work, we fabricate gold/p-type gallium nitride (Au/p-GaN) Schottky junctions tailored for photoelectrochemical studies of plasmon-induced hot-hole capture and conversion. Despite the presence of an interfacial Schottky barrier to hot-hole injection of more than 1 eV across the Au/p-GaN heterojunction, plasmonic Au/p-GaN photocathodes exhibit photoelectrochemical properties consistent with the injection of hot holes from Au nanoparticles into p- GaN upon plasmon excitation. The photocurrent action spectrum of the plasmonic photocathodes faithfully follows the surface plasmon resonance absorption spectrum of the Au nanoparticles and open-circuit voltage studies demonstrate a sustained photovoltage during plasmon excitation. Comparison with Ohmic Au/p-NiO heterojunctions confirms that the vast majority of hot holes generated via interband transitions in Au are sufficiently hot to inject above the 1.1 eV interfacial Schottky barrier at the Au/p-GaN heterojunction. We further investigated plasmon-driven photoelectrochemical CO 2 reduction with the Au/p-GaN photocathodes and observed improved selectivity for CO production over H 2 evolution inmore » aqueous electrolytes. Taken together, our results offer experimental validation of photoexcited hot holes more than 1 eV below the Au Fermi level and demonstrate a photoelectrochemical platform for harvesting hot carriers to drive solar-to-fuel energy conversion.« less

Authors:
ORCiD logo [1];  [1];  [1];  [1]; ORCiD logo [1]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States). Joint Center for Artificial Photosynthesis (JCAP) and Thomas J. Watson Lab. of Applied Physics
Publication Date:
Research Org.:
California Inst. of Technology (CalTech), Pasadena, CA (United States). Joint Center for Artificial Photosynthesis (JCAP)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Swiss National Science Foundation (SNSF)
OSTI Identifier:
1469320
Grant/Contract Number:  
SC0004993; P2EZP2_159101; P300P2_171417
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 18; Journal Issue: 4; Related Information: 10.1021/acs.nanolett.8b00241; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 36 MATERIALS SCIENCE; CO2 reduction; hot carriers; hot holes; Photoelectrochemistry; plasmonic photocathode; Schottky barrier

Citation Formats

DuChene, Joseph S., Tagliabue, Giulia, Welch, Alex J., Cheng, Wen-Hui, and Atwater, Harry A. Hot Hole Collection and Photoelectrochemical CO2 Reduction with Plasmonic Au/p-GaN Photocathodes. United States: N. p., 2018. Web. doi:10.1021/acs.nanolett.8b00241.
DuChene, Joseph S., Tagliabue, Giulia, Welch, Alex J., Cheng, Wen-Hui, & Atwater, Harry A. Hot Hole Collection and Photoelectrochemical CO2 Reduction with Plasmonic Au/p-GaN Photocathodes. United States. doi:10.1021/acs.nanolett.8b00241.
DuChene, Joseph S., Tagliabue, Giulia, Welch, Alex J., Cheng, Wen-Hui, and Atwater, Harry A. Fri . "Hot Hole Collection and Photoelectrochemical CO2 Reduction with Plasmonic Au/p-GaN Photocathodes". United States. doi:10.1021/acs.nanolett.8b00241.
@article{osti_1469320,
title = {Hot Hole Collection and Photoelectrochemical CO2 Reduction with Plasmonic Au/p-GaN Photocathodes},
author = {DuChene, Joseph S. and Tagliabue, Giulia and Welch, Alex J. and Cheng, Wen-Hui and Atwater, Harry A.},
abstractNote = {Harvesting nonequilibrium hot carriers from plasmonic- metal nanostructures offers unique opportunities for driving photo- chemical reactions at the nanoscale. Despite numerous examples of hot electron-driven processes, the realization of plasmonic systems capable of harvesting hot holes from metal nanostructures has eluded the nascent field of plasmonic photocatalysis. In this work, we fabricate gold/p-type gallium nitride (Au/p-GaN) Schottky junctions tailored for photoelectrochemical studies of plasmon-induced hot-hole capture and conversion. Despite the presence of an interfacial Schottky barrier to hot-hole injection of more than 1 eV across the Au/p-GaN heterojunction, plasmonic Au/p-GaN photocathodes exhibit photoelectrochemical properties consistent with the injection of hot holes from Au nanoparticles into p- GaN upon plasmon excitation. The photocurrent action spectrum of the plasmonic photocathodes faithfully follows the surface plasmon resonance absorption spectrum of the Au nanoparticles and open-circuit voltage studies demonstrate a sustained photovoltage during plasmon excitation. Comparison with Ohmic Au/p-NiO heterojunctions confirms that the vast majority of hot holes generated via interband transitions in Au are sufficiently hot to inject above the 1.1 eV interfacial Schottky barrier at the Au/p-GaN heterojunction. We further investigated plasmon-driven photoelectrochemical CO2 reduction with the Au/p-GaN photocathodes and observed improved selectivity for CO production over H2 evolution in aqueous electrolytes. Taken together, our results offer experimental validation of photoexcited hot holes more than 1 eV below the Au Fermi level and demonstrate a photoelectrochemical platform for harvesting hot carriers to drive solar-to-fuel energy conversion.},
doi = {10.1021/acs.nanolett.8b00241},
journal = {Nano Letters},
number = 4,
volume = 18,
place = {United States},
year = {Fri Mar 09 00:00:00 EST 2018},
month = {Fri Mar 09 00:00:00 EST 2018}
}

Journal Article:
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