Ester–Alkyl Linker-Regulated Molecular Folding in Head-to-Head Dimers Enabling >20% Efficiency in Organic Solar Cells - Xin Chen; Jie Wang; Jiong Yang; Tianchen Lu; Yupu Wang; Miaomiao Li; Wendi Shi; Zhaoyang Yao; Xian-Kai Chen; Yanhou Geng; Xiangjian Wan; Yongsheng Chen (Journal of the American Chemical Society, 2026)