One-Step Hydrothermal Synthesis of Sn-Doped Sb 2 Se 3 for Solar Hydrogen Production.

Antimony selenide (Sb 2 Se 3 ) 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 Sb 2 Se 3 photocathodes with improved PEC performance was investigated. We present an in-depth study of the performance enhancement in Sn-doped Sb 2 Se 3 photocathodes using capacitance-voltage (CV), drive-level capacitance profiling (DLCP), and electrochemical impedance spectroscopy (EIS) techniques. The incorporation of Sn 2+ into the Sb 2 Se 3 results in increased carrier density, reduced surface defects, and improved charge separation, thereby leading to improved PEC performance. With a thin Sb 2 Se 3 absorber layer (270 nm thickness), the Sn-doped Sb 2 Se 3 photocathode exhibits an improved photocurrent density of 17.1 mA cm -2 at 0 V versus RHE ( V RHE ) compared to that of the undoped Sb 2 Se 3 photocathode (14.4 mA cm -2 ). This work not only highlights the positive influence of Sn doping on Sb 2 Se 3 photocathodes but also showcases a one-step method to synthesize doped Sb 2 Se 3 with improved optoelectronic properties.