Zhu Tian-Yuan, Shu Da-Jun
National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
J Phys Chem Lett. 2021 Apr 29;12(16):3898-3906. doi: 10.1021/acs.jpclett.1c00702. Epub 2021 Apr 16.
Hybrid perovskites have two properties that are absent in traditional inorganic photovoltaic materials, namely, polarization and mobile ionic defects, the interaction between which may introduce new features into the materials. By using the first-principles calculations, we find that the formation energies of the vacancy defects at a tetragonal MAPbI(110) surface are highly related to the surface polarization. The positive total polarization and local polarization of MA facilitate the formation of surface MA vacancies, whereas the negative total polarization and local polarization of MAI are favorable for the formation of surface iodine vacancies. The phenomena can be explained quantitatively on the basis of the two kinds of Coulomb interactions between the charged defect and the polarization-induced electrostatic field. The comprehensive insights into the interaction between the polarization and the ionic defects in hybrid perovskites can provide a new avenue for defect control for high-performance perovskite solar cells via surface polarization.
混合钙钛矿具有传统无机光伏材料所没有的两种特性，即极化和可移动离子缺陷，它们之间的相互作用可能会给材料带来新特性。通过第一性原理计算，我们发现四方相MAPbI(110)表面空位缺陷的形成能与表面极化高度相关。MA的正总极化和局域极化有利于表面MA空位的形成，而MAI的负总极化和局域极化则有利于表面碘空位的形成。基于带电缺陷与极化诱导静电场之间的两种库仑相互作用，可以对这些现象进行定量解释。对混合钙钛矿中极化与离子缺陷相互作用的全面理解，可以为通过表面极化来控制高性能钙钛矿太阳能电池的缺陷提供一条新途径。
