A highly durable photoelectrode on a bendable yttria-stabilized zirconia substrate for efficient photoelectrochemical water splitting

Abstract

Unlike conventional planar photoelectrodes, bendable photoelectrodes expand their applications through mechanical flexibility, making flexible green energy electronics a promising research domain. A 3 mol% yttria-stabilized zirconia (3YSZ) substrate, providing flexibility and compatibility with oxide layers, facilitates crystallization processes at elevated temperatures, making it more effective than conventional substrates. In this study, bendable BiVO₄ (BVO)-based photoelectrodes were fabricated on 3YSZ substrates using an in situ sequential pulsed laser deposition (PLD) system. The crystallinities, oxidation states, and morphologies were verified, and photoelectrochemical (PEC) performances were evaluated under various bending states. A type II heterojunction was established using a thin WO₃ (WO) layer, improving charge separation and facilitating transfer when employed as a photoanode. The photocurrent density of the heterojunction photoelectrode (BVO/WO) was improved by approximately 2.3 times compared to that of the pure BVO under visible light and remained stable after >10 000 bending cycles with a 6.3 mm bending radius. Photostability tests revealed that both unbent and bent photoanodes maintained 89%, 87%, and 82% of their original photocurrent density after 24 hours, respectively, indicating their remarkable stability. This study underscores the promise of flexible, crystalline photoelectrodes for solar-powered water splitting.