Transient X-ray Diffraction Reveals Nonequilibrium Phase Transition in Thin Films of CH 3 NH 3 PbI 3 Perovskite
Transient X-ray Diffraction Reveals Nonequilibrium Phase Transition in Thin Films of CH 3 NH 3 PbI 3 Perovskite
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瞬态 X 射线衍射揭示 CH 3 NH 3 PbI 3 钙钛矿薄膜中的非平衡相变
DOI：
10.1021/acsenergylett.2c02338
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发表时间：
2023
影响因子：
22
通讯作者：
Schaller, Richard D.
中科院分区：
文献类型：
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作者：
Panuganti, Shobhana;Cuthriell, Shelby A.;Leonard, Ariel A.;Quintero, Michael A.;Laing, Craig C.;Guzelturk, Burak;Zhang, Xiaoyi;Chen, Lin X.;Kanatzidis, Mercouri G.;Schaller, Richard D.
甲基铵三碘化铅的光电子性质可能是由光生载流子与软的可变形晶格之间的耦合引起的。我们使用时间分辨X射线衍射与抽运-探测时间延迟和抽运强度的关系来研究MAPbI 3薄膜的结构动力学。在第一个纳秒期间，晶格在不足以在330 K下热诱导一级热力学相变的激发强度下从四方晶格各向异性地扭曲到立方晶格。高对称性结构，然后通过不同的过渡路径，通过11和236 ns的时间常数弛豫回到起始阶段，无论是在第一纳秒或在以前的报告MAPbI 3。早期的动力学是一致的极化子形成和晶格应变稳定，而较慢的恢复动力学寿命超过辐射复合和相关的亚稳态。这些晶格变形在低功率政权的通量独立性传达相关的光电子学，包括photoprophilics和突出持续参与的非平衡，光诱导晶格重组MAPbI 3功能条件下。
Advantageous optoelectronic properties of methylammonium lead triiodide likely arise from coupling between photogenerated charge-carriers and the soft, deformable lattice. We investigate structural dynamics of MAPbI3films using time-resolved X-ray diffraction versus pump–probe time delay and pump intensity. During the first nanosecond, the lattice anisotropically distorts from tetragonal to cubic at excitation intensities that are insufficient to thermally induce the first-order thermodynamic phase transition at 330 K. The high-symmetry structure then relaxes back to the starting phase with 11 and 236 ns time constants via a different transition pathway than observed either in the first nanosecond or in previous reports for MAPbI3. Early time dynamics are consistent with polaron formation and lattice strain stabilization while the slower recovery dynamics outlive radiative recombination and relate metastability. Fluence-independence of these lattice deformations in the low-power regime conveys relevance to optoelectronics including photovoltaics and highlights sustained involvement of nonequilibrium, photoinduced lattice reorganization in MAPbI3under functional conditions.