摘要： Tin-based perovskites degrade rapidly upon interaction with water and oxygen in air because Sn–I bonds are weak. To address this issue, we developed novel tin perovskites, FASnI(3-x)(SCN)x (x = 0, 1, 2 or 3), employing a pseudohalide, thiocyanate (SCN?), as a replacement for halides and as an inhibitor to suppress the Sn2+/Sn4+ oxidation. The structural and electronic properties of pseudohalide tin perovskites in this series were explored with quantum-chemical calculations employing the plane-wave density-functional-theory (DFT) method; the corresponding results are consistent with the experimental results. Carbon-based perovskite devices fabricated with tin perovskite FASnI(SCN)2 showed about a three-fold enhancement of the device efficiency (2.4 %) relative to the best FASnI3-based device (0.9 %), which we attribute to improved suppression of formation of Sn4+, retarded charge recombination, enhanced hydrophobicity and stronger interactions between Sn and thiocyanate for FASnI(SCN)2 than for FASnI3. After incorporation of phenylethyleneammonium iodide (PEAI, 10 %) and ethylenediammonium diiodide (EDAI2, 5 %) as co-additives, the FASnI(SCN)2 device gave the best photovoltaic performance with JSC/mA cm–2 = 20.17, VOC/mV = 322, FF = 0.574 and overall efficiency of power conversion PCE = 3.7 %. Moreover, these pseudohalide-containing devices display negligible photocurrent–voltage hysteresis and great stability in ambient air conditions.