Wang Zaiyu, Gao Ke, Kan Yuanyuan, Zhang Ming, Qiu Chaoqun, Zhu Lei, Zhao Zhe, Peng Xiaobin, Feng Wei, Qian Zhiyuan, Gu Xiaodan, Jen Alex K-Y, Tang Ben Zhong, Cao Yong, Zhang Yongming, Liu Feng
Frontiers Science Center for Transformative Molecules, In-situ Center for Physical Science, and Center of Hydrogen Science, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China.
Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, 999077, Kowloon, Hong Kong, China.
Nat Commun. 2021 Jan 12;12(1):332. doi: 10.1038/s41467-020-20515-3.
The active layer morphology transition of organic photovoltaics under non-equilibrium conditions are of vital importance in determining the device power conversion efficiency and stability; however, a general and unified picture on this issue has not been well addressed. Using combined in situ and ex situ morphology characterizations, morphological parameters relating to kinetics and thermodynamics of morphology evolution are extracted and studied in model systems under thermal annealing. The coupling and competition of crystallization and demixing are found to be critical in morphology evolution, phase purification and interfacial orientation. A unified model summarizing different phase diagrams and all possible kinetic routes is proposed. The current observations address the fundamental issues underlying the formation of the complex multi-length scale morphology in bulk heterojunction blends and provide useful morphology optimization guidelines for processing devices with higher efficiency and stability.
非平衡条件下有机光伏器件的活性层形态转变对于确定器件的功率转换效率和稳定性至关重要；然而，关于这个问题的一个通用且统一的图景尚未得到很好的解决。通过结合原位和非原位形态表征，在热退火的模型体系中提取并研究了与形态演变的动力学和热力学相关的形态参数。发现结晶和相分离的耦合与竞争在形态演变、相纯化和界面取向中至关重要。提出了一个统一模型，总结了不同的相图和所有可能的动力学途径。当前的观察结果解决了本体异质结共混物中复杂多长度尺度形态形成的基本问题，并为制备具有更高效率和稳定性的器件提供了有用的形态优化指导方针。
