Back contact passivation of Sb₂Se₃ solar cells via antimony trichloride solution

Quasi-one-dimensional antimony selenide (Sb₂Se₃) stands out as a promising light-absorbing material known for its non-toxic nature, excellent stability, earth's abundance, and outstanding optoelectronic performance. However, the surface quality of Sb₂Se₃ thin films is an important factor limiting the efficiency of Sb₂Se₃ solar cells. This article presents a novel approach employing the environmentally friendly and cost-effective inorganic salt, antimony trichloride (SbCl₃), to passivate the surface of Sb₂Se₃ thin films, thus improving the performance of Sb₂Se₃ solar cells. The influence of SbCl₃ passivation on the surface quality of Sb₂Se₃ thin films and the underlying physical mechanisms behind the enhancement of Sb₂Se₃ solar cell performance have been investigated. SbCl₃ passivation can effectively fill the voids between Sb₂Se₃ grains, reduce the surface roughness, and decrease the leakage current of the solar cells. Furthermore, it enhances the light response of the device in the long-wavelength region, reduces the open-circuit voltage losses, effectively lowers the interface recombination rate of charge carriers, and improves carrier transport. As a result of this innovative approach, the efficiency of 6.74% has been recorded. This work provides valuable references for future back contact interface passivation of Sb₂Se₃ solar cells.