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 (J_ph) 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 J_ph under visible and near-IR light, whereas the Bi₂S₃ NC photoanodes exhibited a J_ph of 67% under the same conditions, demonstrating the superiority of AgBiS₂ NC materials for application in highly efficient visible-light-driven PEC devices.