Stable and efficient CdS/Sb2Se3 solar cells prepared by scalable close space sublimation

Abstract Sb 2 Se 3 is a promising candidate for low toxicity, low-cost and high efficiency solar cells. Thin film solar cells employing Sb 2 Se 3 as the absorber have achieved power conversion efficiencies of up to 6.5%. However, these solar cells are typically fabricated using rapid thermal evaporation, a fast deposition technique but suffer from entangled substrate and source temperatures. Here, we report on the fabrication of stable and efficient CdS/Sb 2 Se 3 thin film solar cells using close-space sublimation process, which allows separate control of the source and substrate temperatures. This enables better control of Sb 2 Se 3 film deposition and reduction of interfacial diffusion, leading to higher quality absorber films and improved device heterojunctions. Additionally, we introduced a novel low-cost material 4,4',4'',4'''-(9-octylcarbazole-1,3,6,8-tetrayl)tetrakis(N,N-bis(4-methoxyphenyl)aniline) (CZ-TA) as the hole transport layer (HTL) to create n-i-p structured devices. This CZ-TA HTL reduced the back contact resistance and promoted photogenerated carrier collection, boosting device photo conversion efficiency to 6.84%.