jz0c00249_si_001.pdf (851.69 kB)
Optimizing the Phase-Separated Domain Size of the Active Layer via Sequential Crystallization in All-Polymer Solar Cells
journal contribution
posted on 2020-03-09, 18:04 authored by Jiangang Liu, Shuyi Zeng, Zhiguo Zhang, Jing Peng, Qiuju LiangThe
proper domain size of the active layer plays a key role in
determining the exciton dissociation and charge transport in all-polymer
solar cells (all-PSCs). However, fine-tuning the domain size remains
challenging due to low glass transition temperature and negligible
mixing entropy in polymer blends. Herein, we systematically studied
the influence of “crystallization kinetics” on the domain
size and proposed that if the donor and acceptor crystallize simultaneously,
they are prone to form a large domain, while if sequential crystallization
of the donor and acceptor occurs, a fine phase separation structure
with the proper domain size can be obtained. Taking PBDB-T/PNDI blends
for instance, the domain size was decreased by using sequential crystallization;
meanwhile, the crystallinity and molecular orientation were also optimized,
boosting the power conversion efficiency from 6.55% to 7.78%. This
work provides a novel way to finely tune the heterojunction phase
separation structures.