One-Step Hydrothermal Synthesis of Sn-Doped Sb2Se3 for Solar Hydrogen Production

Antimony selenide (Sb2Se3) has recently been intensively investigated and has achieved significant advancement in photoelectrochemical (PEC) water splitting. In this work, a facile one-step hydrothermal method for the preparation of Sn-doped Sb2Se3 photocathodes with improved PEC performance was investigated. We present an in-depth study of the performance enhancement in Sn-doped Sb2Se3 photocathodes using capacitance–voltage (CV), drive-level capacitance profiling (DLCP), and electrochemical impedance spectroscopy (EIS) techniques. The incorporation of Sn2+ into the Sb2Se3 results in increased carrier density, reduced surface defects, and improved charge separation, thereby leading to improved PEC performance. With a thin Sb2Se3 absorber layer (270 nm thickness), the Sn-doped Sb2Se3 photocathode exhibits an improved photocurrent density of 17.1 mA cm–2 at 0 V versus RHE (VRHE) compared to that of the undoped Sb2Se3 photocathode (14.4 mA cm–2). This work not only highlights the positive influence of Sn doping on Sb2Se3 photocathodes but also showcases a one-step method to synthesize doped Sb2Se3 with improved optoelectronic properties.