Ecofriendly AgBiS₂ Nanocrystal Photoanode for Highly Efficient Visible-Light-Driven Photoelectrochemical Water Splitting

Photoelectrochemical (PEC) hydrogen production via water splitting is a promising sustainable energy conversion method. However, most semiconductors used as photoanodes in PEC splitting exhibit several drawbacks, including ultraviolet (UV)-limited activity, toxic components, and complicated material processing. To address these issues, this study presents a photoanode design strategy for visible-light-driven PEC water splitting in aqueous Na2SO4 solution using a solution-processable AgBiS2 nanocrystal (NC) photoanode. It was observed that the characteristics of the ligand used for the AgBiS2 NC photoanode are crucial in determining its PEC water splitting performance. Moreover, the thiol ligand-capped AgBiS2 NC photoanode shows a higher photocurrent density (Jph) in both 1 sun and visible light than typical TiO2 or Bi2S3 NC photoanodes owing to its excellent electron collection ability and low interfacial charge transfer resistance. The AgBiS2 NC photoanode emits 91% of Jph under visible and near-IR light, whereas the Bi2S3 NC photoanodes exhibited a Jph of 67% under the same conditions, demonstrating the superiority of AgBiS2 NC materials for application in highly efficient visible-light-driven PEC devices.