Highly Sensitive H₂S Gas Sensor Based on a Lead-Free CsCu₂I₃ Perovskite Film at Room Temperature

Recently, there have been reports of lead halide perovskite-based sensors demonstrating their potential for gas sensing applications. However, the toxicity of lead and the instability of lead-based perovskites have limited their applications. This study addressed this issue by developing a H₂S gas sensor based on a lead-free CsCu₂I₃ film prepared using a one-step CVD method. The sensor demonstrated excellent sensing properties, including a high response and selectivity toward H₂S, even at low concentrations (0.2 ppm) at room temperature. Furthermore, a reasonable sensing mechanism was proposed. It is suggested that the sensing mechanism sheds light on the role of defects in perovskite materials, the impact of H₂S as an electron donor, and the occurrence of reversible chemical reactions. These findings suggest that lead-free CsCu₂I₃ has great potential in the field of H₂S gas sensing.