Utilizing the synergistic effect between p–n junction construction and field redistribution to achieve a high photocurrent density Cu2S/CdIn2S4-based photoanode material for next-generation green clean energy

Abstract

Cadmium indium sulfide (CdIn₂S₄), a widely used n-type semiconductor, has been considered a promising photoanode material for photoelectrochemical (PEC) water splitting due to its excellent light response characteristics and suitable energy levels. However, its application in the PEC field is limited by rapid carrier recombination on the surface and severe photocorrosion phenomena. In this study, a novel strategy is proposed by loading Cu₂S onto the surface of CdIn₂S₄ via an ultrasound-assisted method to modify the CdIn₂S₄ photoanode. As a p-type semiconductor, Cu₂S forms a p–n heterojunction with CdIn₂S₄, creating an internal electric field that facilitates charge transport. Additionally, the Cu₂S overlayer acts as a cocatalyst, enhancing the surface reaction kinetics and improving the charge injection efficiency at the photoelectrode/electrolyte interface. The incorporation of Cu₂S also reduces the photocorrosion on the CdIn₂S₄ surface. Experimental results demonstrate that the optimal Cu₂S/CdIn₂S₄ photoanode exhibits a photocurrent of up to 0.3 mA cm⁻² at 1.23 V versus the reversible hydrogen electrode, approximately ten times higher than that of bare CdIn₂S₄. This work offers an effective approach to modulate carrier dynamics, thereby enhancing the PEC performance of photoanodes.