Xu Zhenhua, Wang Liang, Han Qianji, Kamata Yusuke, Ma Tingli
Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Fukuoka 808-0196, Japan.
ACS Appl Mater Interfaces. 2020 Mar 18;12(11):12867-12873. doi: 10.1021/acsami.9b23630. Epub 2020 Mar 4.
In mixed halide perovskite, the halide phase segregation is commonly observed due to halide ion migration, which causes severe stability issues in perovskite devices. Here, we directly revealed the iodide-migration process via potentiostatic treatment in CsPbIBr perovskite. The absence of iodide ions was reduced significantly via a SbS interfacial modification. We further employed the density functional theory (DFT) calculation to optimize the geometry positions at the perovskite interface and radial distribution functions (RDF) to analyze the atom perturbation. The simulation yielded a slight distortion of the perovskite lattice at the SbS-CsPbIBr interface and iodide ion fluctuation was reduced due to the decrease of halide vacancies. In addition, the thermally stimulated current was calculated to evaluate the defect density in the modified perovskite device. Due to the SbS interaction with perovskite, the device became stable against humidity and maintained its photoactivity over 400 h. The champion efficiency of 9.31% with 26.31% improvement was obtained in modified CsPbIBr perovskite solar cells.
在混合卤化物钙钛矿中，由于卤离子迁移，通常会观察到卤化物相分离，这会在钙钛矿器件中引发严重的稳定性问题。在此，我们通过在CsPbIBr钙钛矿中进行恒电位处理直接揭示了碘化物迁移过程。通过SbS界面修饰，碘离子的缺失显著减少。我们进一步采用密度泛函理论（DFT）计算来优化钙钛矿界面处的几何位置，并利用径向分布函数（RDF）分析原子微扰。模拟结果表明，SbS-CsPbIBr界面处的钙钛矿晶格存在轻微畸变，且由于卤化物空位的减少，碘离子波动降低。此外，计算了热激发电流以评估改性钙钛矿器件中的缺陷密度。由于SbS与钙钛矿的相互作用，该器件对湿度具有稳定性，并在400多小时内保持其光活性。在改性CsPbIBr钙钛矿太阳能电池中获得了9.31%的最佳效率，提高了26.31%。
