Issue 44, 2020

Plasmon-induced electron injection into the large negative potential conduction band of Ga2O3 for coupling with water oxidation

Abstract

In this study, an interfacial modification layer was applied to improve the plasmon-induced light energy conversion of a gallium(III) oxide (Ga2O3) photoelectrode, which possesses a much more negative conduction band potential compared with the reduction potential of photons to hydrogen. The plasmon-induced photocurrent generation under visible light irradiation was observed with Au nanoparticle-loaded Ga2O3 (Au-NPs/Ga2O3). An interfacial modification was carried out by depositing a titanium dioxide (TiO2) thin-film layer on Au-NPs/Ga2O3via atomic layer deposition. Since the surface states of TiO2 possess excellent hole-trapping ability, this interfacial modification remarkably improved the generation of plasmon-induced photocurrent in the visible region. The photoelectric conversion efficiency of interfacially modified Au-NPs/Ga2O3 showed a TiO2 thin-film thickness dependence because the migration of hot carriers was suppressed with increasing TiO2 thickness. The Au-NPs/Ga2O3 photoelectrode modified with 2 nm-thick TiO2 showed the best photoelectric conversion performance, and the thermodynamic energy conversion efficiency under irradiation with 600 nm light was approximately two times larger than that of the Au-NPs/TiO2-thin film due to the extremely negative onset potential of Au-NPs/Ga2O3 with TiO2. Therefore, the plasmonic Ga2O3 photoanode with the interfacial TiO2 modification could provide both a high reduction ability for H2 evolution and an oxidation ability for water oxidation, because of the negative conduction band of Ga2O3 and the hole-trapping property from TiO2, respectively.

Graphical abstract: Plasmon-induced electron injection into the large negative potential conduction band of Ga2O3 for coupling with water oxidation

Supplementary files

Article information

Article type
Paper
Submitted
01 sep 2020
Accepted
04 nov 2020
First published
04 nov 2020
This article is Open Access
Creative Commons BY-NC license

Nanoscale, 2020,12, 22674-22679

Plasmon-induced electron injection into the large negative potential conduction band of Ga2O3 for coupling with water oxidation

Y. Wang, X. Shi, T. Oshikiri, S. Zu, K. Ueno and H. Misawa, Nanoscale, 2020, 12, 22674 DOI: 10.1039/D0NR06319C

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