Tao Lin, Yulong Hai, Yongmin Luo, Lingwei Feng, Tao Jia, Jiaying Wu, Ruijie Ma, Top Archie Dela Peña, Yao Li, Zengshan Xing, Mingjie Li, Min Wang, Biao Xiao, Kam Sing Wong, Shengjian Liu, Gang Li
The exploration of high-performance and low-cost wide-bandgap polymer donors remains critical to achieve high-efficiency nonfullerene organic solar cells (OSCs) beyond current thresholds. Herein, the 1,2,3-benzothiadiazole (iBT), which is an isomer of 2,1,3-benzothiadiazole (BT), is used to design wide-bandgap polymer donor PiBT. The PiBT-based solar cells reach efficiency of 19.0%, which is one of the highest efficiencies in binary OSCs. Systemic studies show that isomerization of BT to iBT can finely regulate the polymers' photoelectric properties including i) increasing the extinction coefficient and photon harvest, ii) downshifting the highest occupied molecular orbital energy levels, iii) improving the coplanarity of polymer backbones, iv) offering good thermodynamic miscibility with acceptors...
February 2, 2024: Advanced Materials