Enhanced oxygen anions generation on Bi₂S₃/Sb₂S₃ heterostructure by visible light for trace H₂S detection at room temperature

Bismuth sulfide (Bi₂S₃) possesses unique properties that make it a promising material for effective hydrogen sulfide (H₂S) detection at room temperature. However, when exposed to light, the oxygen anions (O₂^-_(ads)) adsorbed on the surface of Bi₂S₃ can react with photoinduced holes, ultimately reducing the ability to respond to H₂S. In this study, Bi₂S₃/Sb₂S₃ heterostructures were synthesized, producing photoinduced oxygen anions (O₂^-_(hv)) under visible light conditions, resulting in enhanced H₂S sensing capability. The Bi₂S₃/Sb₂S₃ heterostructure sensor exhibits a two-fold increase in sensing response to 500 ppb H₂S under in door light conditions relative to its performance in darkness. Additionally, the sensing response of the Bi₂S₃/Sb₂S₃ sensor (R_a/R_g= 23.3) was approximately five times higher than pure Bi₂S₃. The improved sensing performance of the Bi₂S₃/Sb₂S₃ heterostructures is attributable to the synergistic influence of the heterostructure configuration and light modulation, which enhances the H₂S sensing performance by facilitating rapid charge transfer and increasing active sites (O₂^-_(hv)) when exposed to visible light.