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.