Simultaneous In situ GIWAXS/GISAXS/UV-Vis Reveals the Multiscale Film-formation Kinetics of Blade-coated Organic Photovoltaic Active Layers
Article
Yang, CM, Sun, XK, Zhang, YW et al. (2026). Simultaneous In situ GIWAXS/GISAXS/UV-Vis Reveals the Multiscale Film-formation Kinetics of Blade-coated Organic Photovoltaic Active Layers
. Chinese Journal of Polymer Science (English Edition), 10.1007/s10118-026-3807-2
Yang, CM, Sun, XK, Zhang, YW et al. (2026). Simultaneous In situ GIWAXS/GISAXS/UV-Vis Reveals the Multiscale Film-formation Kinetics of Blade-coated Organic Photovoltaic Active Layers
. Chinese Journal of Polymer Science (English Edition), 10.1007/s10118-026-3807-2
The photovoltaic performance of organic solar cells is critically determined by the multiscale morphology of their bulk heterojunction active layers, whose formation is strongly influenced by solution processing conditions. Therefore, understanding the drying kinetics of blade-coated films is essential for rational morphology regulation and scalable device fabrication. In this study, we established a simultaneous in situ grazing-incidence wide-angle X-ray scattering/grazing-incidence small-angle X-ray scattering/ultraviolet-visible (GIWAXS/GISAXS/UV-Vis) platform to monitor in real time the molecular stacking behavior, mesoscale structural evolution, and optical property changes of blade-coated PTB7-Th:PC71BM blend films during film formation. Synchronized measurements correlate lamellar ordering, mesoscale structure development, and optical response on a common temporal axis. The results show that these events occur over closely related stages of solvent evaporation. Furthermore, the effect of shearing speed on film formation was systematically investigated. Among the examined conditions, a shearing speed of 28 mm/s yielded the most favorable combination of molecular ordering and phase-separated structures, leading to the best device performance. This study provides a versatile multimodal in situ approach for elucidating the film-formation kinetics of solution-processed organic photovoltaic active layers and offers useful guidance for optimizing scalable coating processes. (Figure presented.)
