Exceeding 60% IPCE in BiOI photoanodes via Crystal Growth Control

Bismuth oxyiodide (BiOI), owing to its suitable band gap and excellent light absorption coefficient, has emerged as a highly promising candidate material for photoelectrochemical (PEC) applications. However, its PEC performance is often hindered by poor charge transport and significant carrier recombination. In this study, we propose a combined strategy based on ultrasonic spray pyrolysis (USP) to fabricate high performance BiOI photoanodes by promoting preferential orientation growth, enhancing crystallinity, and optimizing morphology. The optimized BiOI photoanodes exhibited an unprecedented incident photon‐to‐current efficiency (IPCE) exceeding 60% and demonstrated excellent stability. Comprehensive characterizations reveal that our strategy synergistically facilitates carrier transport and reduces bulk recombination. The enhanced charge separation and transport properties of BiOI demonstrated in this study hold significant promise for its practical applications across various fields.