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 longwavelength 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.