Rameez Mohammad, Shahbazi Saeed, Raghunath Putikam, 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 Road, Hsinchu 30010, Taiwan.
Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan.
J Phys Chem Lett. 2020 Apr 2;11(7):2443-2448. doi: 10.1021/acs.jpclett.0c00479. Epub 2020 Mar 13.
Tin perovskites suffer from poor stability and a self-doping effect. To solve this problem, we synthesized novel tin perovskites based on superhalide with varied ratios of tetrafluoroborate to iodide and implemented them into solar cells based on a mesoscopic carbon-electrode architecture because film formation was an issue in applying this material for a planar heterojunction device structure. We undertook quantum-chemical calculations based on plane-wave density functional theory (DFT) methods and explored the structural and electronic properties of tin perovskites FASnI(BF) in the series = 0, 1, 2, and 3. We found that only the = 2 case, FASnI(BF), was successfully produced, beyond the standard FASnI. The electrochemical impedance and X-ray photoelectron spectra indicate that the addition of tin tetrafluoroborate instead of SnI suppressed trap-assisted recombination by decreasing the Sn content. The power conversion efficiency of the FASnI(BF) device with FAI and Sn(BF) in an equimolar ratio improved 72% relative to that of a standard FASnI solar cell, with satisfactory photostability under ambient air conditions.
锡基钙钛矿存在稳定性差和自掺杂效应的问题。为了解决这个问题，我们合成了基于超卤化物的新型锡基钙钛矿，其具有不同比例的四氟硼酸盐与碘化物，并将它们应用于基于介观碳电极结构的太阳能电池中，因为在将这种材料应用于平面异质结器件结构时，成膜是一个问题。我们基于平面波密度泛函理论（DFT）方法进行了量子化学计算，并探索了锡基钙钛矿FASnI(BF)在 = 0、1、2和3系列中的结构和电子性质。我们发现，除了标准的FASnI之外，只有 = 2的情况，即FASnI(BF)成功制备出来。电化学阻抗和X射线光电子能谱表明，添加四氟硼酸锡而不是SnI通过降低Sn含量抑制了陷阱辅助复合。与标准FASnI太阳能电池相比，等摩尔比的FAI和Sn(BF)组成的FASnI(BF)器件的功率转换效率提高了72%，在环境空气条件下具有令人满意的光稳定性。
