光伏系统
二进制数
有机太阳能电池
材料科学
环境科学
化学
电气工程
数学
工程类
算术
作者
Xiangjian Cao,Peiran Wang,Xinyuan Jia,Wenkai Zhao,Hong‐Bin Chen,Zheng Xiao,Jiaqi Li,Xingqi Bi,Jing Wang,Yaxiao Guo,Guankui Long,Chenxi Li,Xiangjian Wan,Yongsheng Chen
标识
DOI:10.1002/anie.202417244
摘要
Given homomorphic fluorine, chlorine and bromine atoms are featured with gradually enlarged polarizability/atomic radius but decreased electronegativity, the rational screen of halogen species and location on small molecular acceptors (SMAs) is quite essential for acquiring desirable molecular packing to boost efficiency of organic solar cells (OSCs). Herein, three isomeric SMAs (CH‐F, CH‐C and CH‐B) are constructed by delicately rebuilding peripheral F, Cl, Br footprints on both central and end units. Such a re‐permutation of peripheral halogens could not only maintain the structural symmetry of SMAs to the maximum, but also acquire extra asymmetric benefits of enhanced dipole moment and intramolecular charge transfer, etc. Moreover, central brominating enhances molecular crystallinity of CH‐B without introducing undesirable steric hindrance on end groups, thus rendering a better balance between high crystallization and domain size control in PM6:CH‐B blend. Further benefitting from the large dielectric constant, small exciton binding energy, optimized molecular packing and great electron transfer integral, CH‐B affords the first class binary OSC efficiency of 19.78%, moreover, the highest efficiency of 18.35% thus far when increasing active layer thickness to ~300 nm. Our successful screening in rebuilding peripheral halogen footprints provides the valuable insight into further rational design of SMAs for record‐breaking OSCs.
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