Improved Phase Stability of Formamidinium Lead Triiodide Perovskite by Strain Relaxation
Improved Phase Stability of Formamidinium Lead Triiodide Perovskite by Strain Relaxation
复制标题
DOI：
10.1021/acsenergylett.6b00457
复制
发表时间：
2016-11-01
影响因子：
22
通讯作者：
Priya, Shashank
中科院分区：
文献类型：
--
作者：
Zheng, Xiaojia;Wu, Congcong;Priya, Shashank
尽管三碘化甲脒铅（FAPbI(3)）具有合适的带隙和良好的热稳定性，但在室温下，特别是在潮湿空气下，从纯黑色钙钛矿相（α相）到不理想的黄色非钙钛矿多晶型物（δ相）的相变阻碍了其实际应用。在这里，我们研究了环境温度下 α 相的固有不稳定性机制，并证明了 (111) 平面中存在驱动相变为 δ 相的各向异性应变晶格。甲基溴化铵 (MABr) 合金化（或 FAPbI(3)-MABr）被发现会引起晶格收缩，从而平衡晶格应变。这导致 alpha-FAPbI3 的稳定性显着提高。使用 FAPbI(3)-MABr 制造的太阳能电池在潮湿空气下表现出显着增强的稳定性。
Though formamidinium lead triiodide (FAPbI(3)) possesses a suitable band gap and good thermal stability, the phase transition from the pure black perovskite phase (alpha-phase) to the undesirable yellow nonperovskite polymorph (delta-phase) at room temperature, especially under humid air, hinders its practical application. Here, we investigate the intrinsic instability mechanism of the alpha-phase at ambient temperature and demonstrate the existence of an anisotropic strained lattice in the (111) plane that drives phase transformation into the delta-phase. Methylammonium bromide (MABr) alloying (or FAPbI(3)-MABr) was found to cause lattice contraction, thereby balancing the lattice strain. This led to dramatic improvement in the stability of alpha-FAPbI3. Solar cells fabricated using FAPbI(3)-MABr demonstrated significantly enhanced stability under the humid air.