Photoelectrochemical water splitting based on chalcopyrite semiconductors: A review

Photoelectrochemical (PEC) water splitting has been garnering immense interest during the last decade as a green approach for hydrogen fuel production. Photoelectrodes as the central components of PEC devices, play a decisive role in their overall performance both in terms of efficiency and stability. Among numerous semiconductors studied for this purpose, chalcopyrite-based photoelectrodes hold great promises for sustainable future applications. Interesting physicochemical characteristics including tunable narrow bandgap, high charge mobility, favorable band edge positions, and low cost have introduced chalcopyrite compounds as ideal options for the photoactive layer. Irrespective of these charismatic properties, comparatively high charge recombination, insufficient chemical stability, and slow fuel production rates hamper industrial employment of these materials. In this regard, a plethora of strategies like addition of an n -type buffer layer, a robust protective layer, and a cocatalyst have been obtained to alleviate these problems, respectively. This review aims to provide a comprehensive insight for the recent advancements made by chalcopyrite-based photoelectrodes. Starting with a brief introduction and some fundamental issues, the chalcopyrite structure and properties are summarized followed by discussing the PEC performance and aforementioned enhancement strategies of these photoelectrodes. In the following sections, some other related semiconductors are also investigated concisely.