Liu Siyu, Wang Jing, Hu Zhe, Duan Zhongtao, Zhang Hao, Zhang Wanlu, Guo Ruiqian, Xie Fengxian
Institute of Future Lighting, Academy for Engineering and Technology, Fudan University, Shanghai, 200433, China.
Institute for Electric Light Sources, School of Information Science and Technology, Fudan University, Shanghai, 200433, China.
Sci Rep. 2021 Oct 14;11(1):20433. doi: 10.1038/s41598-021-99621-1.
The rotation of organic cations is considered to be an important reason for the dynamic changes in stability and photoelectric properties of organic perovskites. However, the specific effect of organic cations rotation on formamidine based perovskite is still unknown. In our work, first-principles calculations based on density functional theory are used to examine the effect of the rotation of formamidine cations in FAPbI and FACsPbI. We have comprehensively calculated the structure, electronic and optical properties of them. We found a coupling effect between formamidine cations rotation and cesium atom. This coupling effect changes the inclination angle of octahedron to regulate electron distribution, band gaps, and optical absorption. Hence, changing the cation orientation and substitution atom is a feasible way to dynamically adjust the energy band, dielectric constant and absorption edge of perovskite. Preparing perovskite with tunable properties is just around the corner through this way.
有机阳离子的旋转被认为是有机钙钛矿稳定性和光电性能动态变化的重要原因。然而，有机阳离子旋转对甲脒基钙钛矿的具体影响仍然未知。在我们的工作中，基于密度泛函理论的第一性原理计算被用于研究FAPbI和FACsPbI中甲脒阳离子旋转的影响。我们全面计算了它们的结构、电子和光学性质。我们发现甲脒阳离子旋转与铯原子之间存在耦合效应。这种耦合效应改变八面体的倾斜角度以调节电子分布、带隙和光吸收。因此，改变阳离子取向和取代原子是动态调节钙钛矿能带、介电常数和吸收边的可行方法。通过这种方式制备具有可调性质的钙钛矿指日可待。
