Sandwich-Nanostructured n-Cu2O/AuAg/p-Cu2O Photocathode with Highly Positive Onset Potential for Improved Water Reduction

Yu-Chang Lin; Liang-Ching Hsu; Chia-Yu Lin; Chao-Lung Chiang; Che-Min Chou; Wen-Wei Wu; San-Yuan Chen; Yan-Gu Lin

doi:10.1021/acsami.9b11737

Sandwich-Nanostructured n-Cu₂O/AuAg/p-Cu₂O Photocathode with Highly Positive Onset Potential for Improved Water Reduction

ACS Appl Mater Interfaces. 2019 Oct 23;11(42):38625-38632. doi: 10.1021/acsami.9b11737. Epub 2019 Oct 14.

Authors

Yu-Chang Lin¹, Liang-Ching Hsu², Chia-Yu Lin³, Chao-Lung Chiang², Che-Min Chou², Wen-Wei Wu¹, San-Yuan Chen^{1

4}, Yan-Gu Lin²

Affiliations

¹ Department of Material Science and Engineering , National Chiao Tung University , Hsinchu 30010 , Taiwan.
² National Synchrotron Radiation Research Center , Hsinchu 30076 , Taiwan.
³ Department of Chemical Engineering , National Cheng Kung University , Tainan 70101 , Taiwan.
⁴ Frontier Research Center on Fundamental and Applied Sciences of Matters , National Tsing Hua University , Hsinchu 30013 , Taiwan.

PMID: 31571473
DOI: 10.1021/acsami.9b11737

Abstract

An n-Cu₂O layer formed a high-quality buried junction with p-Cu₂O to increase the photovoltage and thus to shift the turn-on voltage positively. Mott-Schottky measurements confirmed that the improvement benefited from a positive shift in flat-band potential. The obtained extremely positive onset potential, 0.8 V_RHE in n-Cu₂O/AuAg/p-Cu₂O, is comparable with measurements from water reduction catalysts. The AuAg alloy sandwiched between the homojunction of n-Cu₂O and p-Cu₂O improved the photocatalytic performance. This alloy both served as an electron relay and promoted electron-hole pair generation in nearby semiconductors; the charge transfer between n-Cu₂O and p-Cu₂O in the sandwich structure was measured with X-ray absorption spectra. The proposed sandwich structure can be considered as a new direction for the design of efficient solar-related devices.

Keywords: copper(I) oxide; localized surface plasmon resonance; photocathode; sandwich structure; solar water splitting.