Open Access15.3% Efficiency All‐Small‐Molecule Organic Solar Cells Achieved by a Locally Asymmetric F, Cl Disubstitution Strategy
Author(s) -
Hu Dingqin,
Yang Qianguang,
Zheng Yujie,
Tang Hua,
Chung Sein,
Singh Ranbir,
Lv Jie,
Fu Jiehao,
Kan Zhipeng,
Qin Bo,
Chen Qianqian,
Liao Zhihui,
Chen Haiyan,
Xiao Zeyun,
Sun Kuan,
Lu Shirong
Publication year - 2021
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.202004262
Subject(s) - acceptor , organic solar cell , energy conversion efficiency , materials science , small molecule , active layer , molecule , photovoltaic system , dipole , optoelectronics , nanotechnology , layer (electronics) , chemistry , polymer , organic chemistry , physics , electrical engineering , biochemistry , thin film transistor , engineering , composite material , condensed matter physics
Single junction binary all‐small‐molecule (ASM) organic solar cells (OSCs) with power conversion efficiency (PCE) beyond 14% are achieved by using non‐fullerene acceptor Y6 as the electron acceptor, but still lag behind that of polymer OSCs. Herein, an asymmetric Y6‐like acceptor, BTP‐FCl‐FCl, is designed and synthesized to match the recently reported high performance small molecule donor BTR‐Cl, and a record efficiency of 15.3% for single‐junction binary ASM OSCs is achieved. BTP‐FCl‐FCl features a F,Cl disubstitution on the same end group affording locally asymmetric structures, and so has a lower total dipole moment, larger average electronic static potential, and lower distribution disorder than those of the globally asymmetric isomer BTP‐2F‐2Cl, resulting in improved charge generation and extraction. In addition, BTP‐FCl‐FCl based active layer presents more favorable domain size and finer phase separation contributing to the faster charge extraction, longer charge carrier lifetime, and much lower recombination rate. Therefore, compared with BTP‐2F‐2Cl, BTP‐FCl‐FCl based devices provide better performance with FF enhanced from 71.41% to 75.36% and J sc increased from 22.35 to 24.58 mA cm −2 , leading to a higher PCE of 15.3%. The locally asymmetric F, Cl disubstitution on the same end group is a new strategy to achieve high performance ASM OSCs.