A Novel Photocathode Material for Sunlight‐Driven Overall Water Splitting: Solid Solution of ZnSe and Cu(In,Ga)Se2
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Authors: | Hiroyuki Kaneko Tsutomu Minegishi Mamiko Nakabayashi Naoya Shibata Yongbo Kuang Taro Yamada Kazunari Domen |
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Affiliation: | 1. Department of Chemical System Engineering, The University of Tokyo, Bunkyo‐ku, Tokyo, Japan;2. JST, PRESTO, Bunkyo‐ku, Tokyo, Japan;3. Institute of Engineering Innovation, The University of Tokyo, Bunkyo‐ku, Tokyo, Japan;4. Department of Chemical System Engineering, The University of Tokyo, Kashiwa‐Shi, Chiba, Japan |
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Abstract: | Thin films of a solid solution of ZnSe and CuIn0.7Ga0.3Se2 ((ZnSe) x (CIGS) 1–x ) are prepared by co‐evaporation. Structural characterization reveals that the ZnSe and CIGS form a solid solution with no phase separation. (ZnSe)0.85(CIGS)0.15‐based photocathodes modified with Pt, Mo, Ti, and CdS exhibit a photocurrent of 7.1 mA cm?2 at 0 VRHE, and a relatively high onset potential of 0.89 VRHE under simulated sunlight. A two‐electrode cell containing a (ZnSe)0.85(CIGS)0.15 photocathode and a BiVO4‐based photoanode has an initial solar‐to‐hydrogen conversion efficiency of 0.91%, which is one of the highest values reported for a photoanode–photocathode combination. Thus, (ZnSe)0.85(CIGS)0.15 is a promising photocathode material for efficient photoelectrochemical water splitting. |
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Keywords: | chalcopyrites hydrogen photocathodes photoelectrochemistry, water splitting |
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