Effective Dopants Pb and Pb-SiW12 to Enhance Sb2S3-Based Photodetector Performance

Abstract

Sb₂S₃ has excellent photovoltaic properties, but the performance of its photovoltaic devices still needs to be improved. The main issues hindering its photovoltaic performance are the poor carrier transport ability and the significant charge recombination. Doping strategies play a key role in addressing these issues. This study investigates the effect of Pb(CH₃COO)₂ (Pb) and [Pb(DMF)₇]₂[SiW₁₂O₄₀] 2DMF (Pb-SiW₁₂) doping on the photovoltaic properties of Sb₂S₃ thin films. It is found that the intensity of diffraction peaks on the (130) crystal plane of Pb-doped Sb₂S₃ and the (221) crystal plane of Pb-SiW₁₂@Sb₂S₃ is increased, which enhances the crystallinity of the films. Meanwhile, Pb and Pb-SiW₁₂ doping narrow the bandgap (1.69 eV) of Sb₂S₃ to 1.65 eV and 1.62 eV. Electrochemical tests show that the carrier concentration and carrier lifetime are increased. The Pb-doped Sb₂S₃ photodetector photocurrent of 14 μA, 7 times higher than the 2 μA pristine Sb₂S₃ photodetector. It exhibits a responsivity of 13.9 mA/W and detectivity of 1.2×10¹¹ Jones. The Pb-SiW₁₂@Sb₂S₃ photodetector photocurrent is 11 μA. Pb-SiW₁₂ can immobilize Pb while reducing the amount of Pb. The methodology in this work provides a way to improve the performance of Sb₂S₃ thin-film photodetectors.