Ma Yabin, Du Xinyi, Chen Ran, Zhang Lu, An Zhongwei, Jen Alex K-Y, You Jiaxue, Liu Shengzhong Frank
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, International Joint Research Center of Shaanxi Province for Photoelectric Materials Science, Institute for Advanced Energy Materials, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710119, China.
Department of Materials Science and Engineering, Hong Kong Institute for Clean Energy, City University of Hong Kong, Kowloon, Hong Kong, 710119, China.
Adv Mater. 2023 Dec;35(49):e2306947. doi: 10.1002/adma.202306947. Epub 2023 Oct 26.
Solution crystallization in film devices has attracted broad interest from various fields such as perovskite solar cells. However, the detailed perovskite crystallization kinetics remain unclear due to the difficulty of in situ observation of grain cluster growth during annealing. This article presents the development of an in situ laser scanning confocal polarized microscopy with a temperature-controlled stage to observe nucleation and growth of perovskite crystal clusters. It is found that enhanced interactions by a liquid crystal with perovskite form a new intermediate complex that induces diffusion-controlled growth according to Avrami equation. The retarded cluster growth (63 nm s ) originates from enlarged diffusion activation energy 40 kJ mol compared with 152 nm s and 37 kJ mol for the Control film during annealing. Finally, the optimized perovskite films with enhanced crystallographic and optical characteristics are applied in solar cells to achieve a champion efficiency of 24.53% with open circuit voltage of 1.172 V and fill factor of 82.78%. The bare device without any protection maintains 89% of its initial efficiency after 6600 h of aging in ambient environment. This work implies that the in situ observation using fluorescence microscopy is a critical for understanding of crystallization kinetics in film devices.
薄膜器件中的溶液结晶已引起钙钛矿太阳能电池等各个领域的广泛关注。然而，由于在退火过程中难以原位观察晶粒簇的生长，钙钛矿详细的结晶动力学仍不清楚。本文介绍了一种带有控温台的原位激光扫描共聚焦偏振显微镜的研制，用于观察钙钛矿晶体簇的成核和生长。研究发现，液晶与钙钛矿之间增强的相互作用形成了一种新的中间络合物，该络合物根据阿弗拉米方程诱导扩散控制生长。与退火过程中对照膜的152 nm/s和37 kJ/mol相比，簇生长的延迟（63 nm/s）源于扩散活化能增大至40 kJ/mol。最后，将具有增强晶体学和光学特性的优化钙钛矿薄膜应用于太阳能电池，实现了24.53%的最佳效率，开路电压为1.172 V，填充因子为82.78%。在环境中老化6600小时后，没有任何保护的裸器件保持其初始效率的89%。这项工作表明，使用荧光显微镜进行原位观察对于理解薄膜器件中的结晶动力学至关重要。
