ma7b01509_si_001.pdf (2.3 MB)
2D/1A Strategy to Regulate Film Morphology for Efficient and Stable Nonfullerene Organic Solar Cells
journal contribution
posted on 2017-08-22, 21:03 authored by Xiaoyu Liu, Jialin Wang, Jiajun Peng, Ziqi LiangRecently, the ternary blend method
has been successfully applied
to nonfullerene organic solar cells (OSCs) and enhanced the device
performance by utilizing complementary optical absorption. Here we
demonstrate the two polymer donors and one small-molecule acceptor
(i.e., 2D/1A) strategy to finely regulate the blend film morphology
in fullerene-free OSCs. One crystalline polymer donor, PffBT4T–2OD,
can act as an effective morphology regulator for a benchmark blend
of PTB7–Th and ITIC, leading to appropriate phase-separated
morphology, suppressed charge recombination, efficient charge transport
and high carrier mobility. The resulting solvent additive- and annealing-free
fabricated bulk-heterojunction OSCs show the best power conversion
efficiency (PCE) of 8.22% with a significant increase of fill factor
compared to their binary counterparts. Importantly, such ternary OSCs
when processed under ambient condition retain excellent device performance
with a PCE of 7.57%, indicative of good air-stability.