Designing an asymmetrical isomer to promote the LUMO energy level and molecular packing of a non-fullerene acceptor for polymer solar cells with 12.6% efficiency

Wei Gao; Qiaoshi An; Cheng Zhong; Zhenghui Luo; Ruijie Ming; Miao Zhang; Yang Zou; Feng Liu; Fujun Zhang; Chuluo Yang

doi:10.1039/c8sc02018c

Designing an asymmetrical isomer to promote the LUMO energy level and molecular packing of a non-fullerene acceptor for polymer solar cells with 12.6% efficiency

Chem Sci. 2018 Aug 20;9(42):8142-8149. doi: 10.1039/c8sc02018c. eCollection 2018 Nov 14.

Authors

Wei Gao^{1

2}, Qiaoshi An³, Cheng Zhong¹, Zhenghui Luo¹, Ruijie Ming¹, Miao Zhang³, Yang Zou², Feng Liu⁴, Fujun Zhang³, Chuluo Yang^{1

2}

Affiliations

¹ Department of Chemistry , Hubei Key Lab on Organic and Polymeric Optoelectronic Materials , Wuhan University , Wuhan , 430072 , People's Republic of China . Email: clyang@whu.edu.cn.
² College of Materials Science and Engineering , Shenzhen University , Shenzhen , 518060 , People's Republic of China.
³ Key Laboratory of Luminescence and Optical Information , Ministry of Education , Beijing Jiaotong University , Beijing , 100044 , People's Republic of China . Email: fjzhang@bjtu.edu.cn.
⁴ Department of Physics and Astronomy , Collaborative Innovation Center of IFSA (CICIFSA) , Shanghai Jiaotong University , Shanghai 200240 , P. R. China . Email: fengliu82@sjtu.edu.cn.

Abstract

Isomers with small structural changes usually exhibit different properties. Rationally designing isomers of some high-performance SMAs can further enhance their function. In this work, an asymmetrical small molecule acceptor (SMA) MeIC1 isomerized from MeIC is reported. Compared with the symmetrical MeIC, the asymmetrical isomer showed almost the same absorption range but an elevated LUMO energy level and simultaneously enhanced π-π stacking and electron mobility by replacing the thieno[3,2-b]thiophene unit with a larger sized dithieno[3,2-b:2',3'-d]thiophene unit in the ladder-type core of MeIC. As a result, the MeIC1-based PSCs achieved a higher PCE up to 12.58% with a promoted V _oc and J _sc and an unchanged FF compared with those of MeIC-based PSCs when blended with PBDB-T. This work reveals that asymmetrical isomerization is effective for PCE promotion.