Cu2O/InGaN heterojunction thin films with enhanced photoelectrochemical activity for solar water splitting
Document Type
Article
Publication Date
8-1-2020
Abstract
We study Cu2O/InGaN heterojunction thin films with different thicknesses of Cu2O layer as a photoanode in photoelectrochemical (PEC) water splitting cell. Results show that the bandgap energy of Cu2O/InGaN heterojunction thin films is 2.60-2.72 eV and, according to Vegard's law, the indium content of the InGaN thin film is 22%. Electrochemical impedance spectroscopy shows the charge-transfer resistance value of about 0.4 k Omega for the optimized sample revealing enhanced charge separation and transfer at the interface. A maximum photocurrent density of 0.16 mA cm(-2 )at 0.5 V vs. Ag/AgCl was obtained for the Cu2O/InGaN heterojunction thin films with an overall thickness of 250 nm. The obtained value is 4.2 and 3.2 times higher than that of pure InGaN and Cu2O thin films photoanodes, respectively. We showed charge separation mechanism in the Cu2O/InGaN heterojunction photoelectrodes. According to our model, gradient energy bandgap reduce the recombination rate of photo-induced electron-hole pairs, and significantly enhance the PEC performance. (C) 2020 Elsevier Ltd. All rights reserved.
Keywords
Cu2O/InGaN heterojunction, Photoelectrochemical behavior, Solar water splitting, Thin films
Divisions
PHYSICS
Funders
Iranian National Science Foundation,University of Minnesota,ran National Science Foundation,Universiti Malaya (Grant No. GPF034B-2018)
Publication Title
Renewable Energy
Volume
156
Publisher
Pergamon-Elsevier Science Ltd
Publisher Location
THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND