# π-Extended Nonfullerene Acceptor for Compressed Molecular Packing in Organic Solar Cells To Achieve over 20% Efficiency

“π-Extended Nonfullerene Acceptor for Compressed Molecular Packing in Organic Solar Cells To Achieve over 20% Efficiency” (2024), by Yuandong Sun et al. Engineering research paper. Original abstract below, unchanged. No free PDF was found.

- Authors: Yuandong Sun, Liang Wang, Chuanhang Guo, Jingtao Xiao, Chenhao Liu, Chen Chen, Weiyi Xia, Zirui Gan, Jingchao Cheng, Jinpeng Zhou et al.
- Published: April 19, 2024
- Field: Engineering
- DOI: https://doi.org/10.1021/jacs.4c01503
- Source: https://doi.org/10.1021/jacs.4c01503

## Abstract

Organic photovoltaics (OPVs) suffer from a trade-off between efficient charge transport and suppressed nonradiative recombination due to the aggregation-induced luminance quenching of organic semiconductors. To resolve this grand challenge, a π-extended nonfullerene acceptor (NFA) B6Cl with large voids among the honeycomb network is designed and introduced into photovoltaic systems. We find that the presence of a small amount of (i.e., 0.5 or 1 wt %) B6Cl can compress the molecular packing of the host acceptor L8-BO, leading to shortened π–π stacking distance from 3.59 to 3.50 Å (that will improve charge transport) together with ordered alkyl chain packing (that will inhibit nonradiative energy loss due to the suppressed C–C and C–H bonds vibrations), as validated by high-energy X-ray scattering measurements. This morphology transformation ultimately results in simultaneously improved J SC, FF, and V OC of OPVs . As a result, the maximum PCEs of PM6:L8-BO and D18:L8-BO are increased from 19.1 and 19.3% to 19.8 and 20.2%, respectively, which are among the highest values for single-junction OPVs. The university of B6Cl to increase the performance of OPVs is further evidenced in a range of polymer:NFA OPVs.

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