Sun Yijing, Yao Qianqian, Xing Weiwei, Jiang He, Li Yingbo, Chen Miao, Zhang Xiaoyue, Xiong Weiming, Zhu Wenpeng, Zheng Yue
Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China.
ACS Appl Mater Interfaces. 2022 May 18;14(19):22582-22592. doi: 10.1021/acsami.2c01632. Epub 2022 May 9.
Organic-inorganic hybrid perovskite (OIHP) polycrystalline films are the key light-absorbing layers of laminated-structure OIHP-based devices that have attracted increasing attention in photoelectronics and flexible electronics. Internal stresses induced by the mismatched responses of laminated layers to long-term and cyclic multiphysical fields generate time-dependent mechanical deformation in OIHP polycrystalline films, which makes the mechanical constitution relation of great significance. However, few studies focus on either the mechanical properties and behaviors of OIHP polycrystalline films or the underlying mechanism coupled with the grain structure and ion diffusion. Here, we uncovered the heterogeneous viscoelasticity of MAPbBr films strongly correlated with the grain structure. Combining experiments and modeling, we revealed that the organic cation diffusion from grain interiors to grain boundaries leads to heterogeneity in the chemical distribution and viscoelastic modulus. Our work provides the nanomechanical understanding of the OIHP polycrystalline films that are crucial for safety design and performance optimization in OIHP-based electronics.
有机-无机杂化钙钛矿（OIHP）多晶薄膜是层状结构OIHP基器件的关键吸光层，在光电子学和柔性电子学领域受到越来越多的关注。层状层对长期和循环多物理场的不匹配响应所引起的内应力，会在OIHP多晶薄膜中产生随时间变化的机械变形，这使得机械本构关系具有重要意义。然而，很少有研究关注OIHP多晶薄膜的力学性能和行为，或者与晶粒结构和离子扩散相关的潜在机制。在这里，我们揭示了MAPbBr薄膜的非均匀粘弹性与晶粒结构密切相关。通过结合实验和建模，我们发现有机阳离子从晶粒内部扩散到晶界会导致化学分布和粘弹性模量的不均匀性。我们的工作为OIHP多晶薄膜提供了纳米力学理解，这对于基于OIHP的电子产品的安全设计和性能优化至关重要。
