High-efficiency and stable Sb₂(S,Se)₃ thin film solar cells with phthalocyanine as a hole transport layer

Antimony selenosulphide (Sb-2(S,Se)(3)) has undergone rapid development recently owing to its adjustable band gap, high light-absorption coefficient and excellent optoelectronic properties as well as its safety, non-toxicity and low-cost aspects. High-efficiency Sb-2(S,Se)(3) thin film solar cells use Spiro-OMeTAD hollow-hole transport materials to construct n-i-p (n-type, intrinsic and p-type) structures; however, the poor stability and high cost of Spiro-OMeTAD limit its large-scale application in Sb-2(S,Se)(3) solar cells. Herein, in order to address these problems, we report stable and efficient Sb-2(S,Se)(3) solar cells enabled by various phthalocyanine hole transport layers (HTLs). The pure Pc and Sb-2(S,Se)(3) absorbers exhibited improved valence band alignment compared to Spiro-OMeTAD. The device with the tuning concentration of phthalocyanine solution shows high homogeneity and carrier transport. The increased hole transport capability of the Pc material facilitated a higher J(SC) in the Pc device, resulting in a photoelectric conversion efficiency of 8.42%. Furthermore, the Pc device maintained an initial efficiency of 97.5% after 700 h compared to the Spiro-OMeTAD-based device. These results demonstrate the great potential of the Pc hole transport layer and provide new insights into the selection of HTL materials for the preparation of highly efficient Sb-2(S,Se)(3) thin film solar cells.