Low‐Pressure Vapor‐Assisted Solution Process for Thiocyanate‐Based Pseudohalide Perovskite Solar Cells

In this report, we fabricated thiocyanate‐based perovskite solar cells with low‐pressure vapor‐assisted solution process (LP‐VASP) method. Photovoltaic performances are evaluated with detailed materials characterizations. Scanning electron microscopy images show that SCN‐based perovskite films fabricated using LP‐VASP have long‐range uniform morphology and large grain sizes up to 1 μm. The XRD and Raman spectra were employed to observe the characteristic peaks for both SCN‐based and pure CH3NH3PbI3 perovskite. We observed that the Pb(SCN)2 film transformed to PbI2 before the formation of perovskite film. X‐ray photoemission spectra (XPS) show that only a small amount of S remained in the film. Using LP‐VASP method, we fabricated SCN‐based perovskite solar cells and achieved a power conversion efficiency of 12.72 %. It is worth noting that the price of Pb(SCN)2 is only 4 % of PbI2. These results demonstrate that pseudo‐halide perovskites are promising materials for fabricating low‐cost perovskite solar cells.