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

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.