Rameez Mohammad, Lin Eric Yan-Ru, Raghunath Putikam, Narra Sudhakar, Song Donghoon, Lin Ming-Chang, Hung Chen-Hsiung, Diau Eric Wei-Guang
Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan.
Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan.
ACS Appl Mater Interfaces. 2020 May 13;12(19):21739-21747. doi: 10.1021/acsami.0c03704. Epub 2020 Apr 28.
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(SCN) ( = 0, 1, 2, or 3), by employing a pseudohalide, thiocyanate (SCN), as a replacement for halides and as an inhibitor to suppress the Sn/Sn oxidation. The structural and electronic properties of pseudohalide tin perovskites in this series were explored with quantum-chemical calculations by 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) showed about a threefold enhancement of the device efficiency (2.4%) relative to that of the best FASnI-based device (0.9%), which we attribute to the improved suppression of the formation of Sn, retarded charge recombination, enhanced hydrophobicity, and stronger interactions between Sn and thiocyanate for FASnI(SCN) than those for FASnI. After the incorporation of phenylethyleneammonium iodide (PEAI, 10%) and ethylenediammonium diiodide (EDAI, 5%) as coadditives, the FASnI(SCN) device gave the best photovoltaic performance with = 20.17 mA cm, = 322 mV, fill factor (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.
由于Sn-I键较弱，锡基钙钛矿在与空气中的水和氧气相互作用时会迅速降解。为了解决这个问题，我们通过使用拟卤化物硫氰酸盐（SCN）替代卤化物并作为抑制Sn/Sn氧化的抑制剂，开发了新型锡钙钛矿FASnI(SCN)（ = 0、1、2或3）。采用平面波密度泛函理论（DFT）方法，通过量子化学计算探索了该系列拟卤化物锡钙钛矿的结构和电子性质；相应结果与实验结果一致。用锡钙钛矿FASnI(SCN)制备的碳基钙钛矿器件的器件效率（2.4%）相对于最佳的基于FASnI的器件（0.9%）提高了约三倍，我们将其归因于对Sn形成的抑制作用增强、电荷复合延迟、疏水性增强以及FASnI(SCN)中Sn与硫氰酸盐之间的相互作用比FASnI更强。在加入苯乙烯碘化铵（PEAI，10%）和乙二胺二碘化物（EDAI，5%）作为共添加剂后，FASnI(SCN)器件表现出最佳的光伏性能， = 20.17 mA cm， = 322 mV，填充因子（FF） = 0.574，功率转换总效率PCE = 3.7%。此外，这些含拟卤化物的器件在环境空气条件下显示出可忽略不计的光电流 - 电压滞后和良好的稳定性。
