Amorphous Manganese Sulfide Enables Efficient and Stable All-Inorganic Antimony Selenosulfide Solar Cells

Chen Qian1, Jianjun Li1, Kaiwen Sun1, Chenhui Jiang2, Jialiang Huang1, Rongfeng Tang2, Martin Green1, Bram Hoex1, Tao Chen2, Xiaojing Hao1 1University of New South Wales, Sydeny, Australia /2University of Science and Technology of China, Hefei, China

Antimony selenosulfide, Sb2(S,Se)3, has emerged as a promising light-harvesting material for its high absorption coefficient, suitable bandgap, low-toxic and low-cost constituents. An n-i-p device architecture has to be adopted in Sb2(S,Se)3 based solar cell to accommodate its anisotropic property and low carrier mobility. It has been realized that the high-efficiency antimony selenosulfide solar cells are obtained exclusively using Spiro-OMeTAD as the hole-transporting material. However, the poor stability and high cost of Spiro-OMeTAD may restrict its potential in practical applications in solar cells. Here, we report an all-inorganic Sb2(S,Se)3 solar cell enabled by using an evaporated inorganic manganese sulfide (MnS) hole-transporting layer. We identify the critical factors that influence the device performance: the carrier concentration and work function of MnS layer, and the junction-quality of MnS/Sb2(S,Se)3 interface, thus obtaining the highest efficiency of 9.7% in all-inorganic Sb2(S,Se)3 solar cells. In addition, the unencapsulated Sb2(S,Se)3 solar cell with MnS demonstrates remarkably enhanced stability than those fabricated using conventional Spiro-OMeTAD as the hole-transporting layer. Our findings provide a new understanding and practical material fabrication strategy regarding how to obtain high-efficiency solar cells when using MnS as a hole-transporting layer. This low-cost, efficient, stable, and up-scalable MnS hole-transporting layer may also be applicable to other emerging solar cells, rendering a better pathway toward commercialization.