Stability and Efficiency Enhancement of Antimony Selenosulfide Solar Cells with Inorganic SnS-Modified Nickel Oxide Hole Transport Materials

Antimony selenosulfide (Sb-2(S,Se)(3)) has been emerging as a promising light absorber owing to its tunable bandgap (1.1-1.7 eV), high absorption coefficient (>10(5) cm(-1)), and excellent phase and environmental stability. Lithium salt-doped 2,2 ',7,7 '-tetrakis(N,N-di-p-methoxy-phenylamine)-9,9 '-spirobifluorene (spiro-OMeTAD) has been generally used as the hole transport layer (HTL) in these high-efficiency antimony selenosulfide solar cells so far. However, the lithium-ion reactions and migration in this HTL may cause serious challenges for the stability of these solar cells. Herein, stable and low-cost tin monosulfide (SnS) nanoparticles surface-modified nickel oxide (NiOx) as an inorganic hole transport layer to fabricate highly efficient and stable all-inorganic solar cells is developed. It is found that NiOx films not only demonstrate a higher conductivity but also form better energy band alignment after SnS surface treatment. Consequently, the power conversion efficiency of the full inorganic Sb-2(S,Se)(3) solar cells increases from 4.85% to 6.41%. Most importantly, the devices also demonstrate much improved thermal, moisture, and long-term stabilities as compared to the solar cells with spiro-OMeTAD hole transport layer.