Breakthrough in the large area photoanode fabrication process: high concentration precursor solution with solvent mixing and one step spin coating for high PEC performance of BiVO4

Abstract

Advancements in the efficiency of hydrogen production via photoelectrochemical water splitting have led to a focus on scalability, ease of fabrication, and cost-effectiveness. Yet, challenges such as prolonged processing times and complex procedures persist, demanding innovative breakthroughs. Our study presents a streamlined method for fabricating high-efficiency BiVO₄ films for PEC application, employing one-step spin coating with high-concentration precursor solutions, making it apt for large-scale deployment. Optimizing solvent and precursor ratios led to a notable photocurrent density of 5.03 mA cm⁻² at 1.23 V_RHE. This enhancement could be attributed to an increase in light absorption owing to an increase in the (040) crystal plane and Mie scattering, optimized film thickness, large grain size and decreased surface dangling bonds, resulting in enhanced carrier density and improved carrier transfer and transport. This approach enabled the cost-effective production of large-area BiVO₄ photoanodes, which effectively generated high current in a PEC-PV system through self-driven solar water splitting. Our study highlights a pathway towards commercial-scale solar-powered hydrogen production technologies.