Enhanced Performance of Sb2S3 Solar Cells via Coevaporated MnS–PbS Composite Hole Transport Layers

Antimony sulfide (Sb2S3) has emerged as a promising photoactive material due to its high light absorption capability. However, the organic Spiro-OMeTAD hole transport layer (HTL) poses a severe challenge to highly efficient Sb2S3 solar cells because of its high cost and poor stability. To address these issues, a MnS–PbS composite HTL was fabricated via the coevaporation process for the first time. By tuning the MnS:PbS ratio, the microstructure, carrier transport, and energy band alignment at the Sb2S3/ MnS–PbS interface were optimized. The high carrier mobility of PbS films and the high carrier concentration of MnS films enabled the MnS–PbS composite HTL possessing the superior conductivity. Devices employing the optimized MnS–PbS HTL achieved a champion power conversion efficiency of 6.60%, with significant improvements in short-circuit current, fill factor, and photostability due to the enhanced hole transport, suppressed recombination, and reduced photocurrent loss. This facile coevaporated composite HTL demonstrates a significant potential for efficient fully inorganic Sb2S3 solar cells.