Chang Liu
(, ), Zhaozhao Bi
(, ), Ke Wang
(, ), Jingming Xin
(, ), Jingwei Xue
(, ), Nuo Chen
(, ), Linlin An
(, ), Ying Chen
(, ), Jiangang Liu
(, ), Brian A. Collins, Long Jiang
(, ), Wei Ma
(, )
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引用次数: 0
Abstract
Slot-die coating with halogen-free solvents is a promising scalable fabrication strategy for organic solar cells (OSCs). However, the complex interplay between long-time-scale solute diffusion and microstructural evolution during the coating process remains poorly understood, limiting further optimization of morphology and device performance. In this study, we elucidate the critical role of solution viscosity in regulating phase separation and aggregation kinetics. Specifically, lower solution viscosity enhances solute diffusion, accelerating molecular aggregation while suppressing liquid-liquid phase separation (LLPS). Notably, we observe that in three different systems with varying crystallinity and immiscibility (PM6:Y6, PTQ10:Y6, and D18:Y6), the optimal processing conditions for peak device efficiency consistently correspond to a nearly identical solution viscosity (∼0.8 mPa s), despite variations in optimal processing temperatures. In situ characterizations reveal that at this viscosity, all three systems exhibit constrained LLPS and rapid molecular aggregation, promoting the formation of finely structured, continuous nanoscale domains. These findings establish solution viscosity as a universal governing parameter for morphology control in printed active layers. By providing a fundamental framework for understanding viscosity-mediated phase separation, this work offers valuable insights for advancing high-throughput, environmentally friendly printing techniques for high-efficiency OSCs.
期刊介绍:
Science China Materials (SCM) is a globally peer-reviewed journal that covers all facets of materials science. It is supervised by the Chinese Academy of Sciences and co-sponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China. The journal is jointly published monthly in both printed and electronic forms by Science China Press and Springer. The aim of SCM is to encourage communication of high-quality, innovative research results at the cutting-edge interface of materials science with chemistry, physics, biology, and engineering. It focuses on breakthroughs from around the world and aims to become a world-leading academic journal for materials science.