Homojunction Back Contacts Enable Efficient Cu2O Photocathodes
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Published on: September 12, 2014
Jinshui Cheng1,2, Linxiao Wu1, Keming Li3
1Institute of Photoelectronic Thin Film Devices and Technology, State Key Laboratory of Photovoltaic Materials and Cells, Tianjin Key Laboratory of Efficient Solar Energy Utilization, Ministry of Education Engineering Research Center of Thin Film Photoelectronic Technology, Nankai University, Tianjin, China.
Abstract:
Enhancing carrier separation and extraction is crucial to achieve efficient metal oxide photoelectrodes for photoelectrochemical (PEC) water splitting. Here, we report a highly efficient Cu2O photocathode based on p+/p back-contact homojunction. The homojunction significantly enhances hole-selective extraction while suppressing electron backflow at the back-contact interface, leading to marked improvements in PEC performance. The optimized photocathode delivers a hydrogen evolution reaction (HER) onset potential of 1.1 V and a saturated photocurrent density of ∼8.0 mA cm-2. Furthermore, the p+/p back homojunction design enables the fabrication of a semi-transparent Cu2O photocathode, which, when integrated with a perovskite solar cell in a tandem configuration, achieves a solar-to-hydrogen (STH) efficiency of 7.31%. This work demonstrates a viable strategy for advancing metal oxide photoelectrodes via homojunction engineering.
