A nonfullerene acceptor, isoIDITC, capable of exhibiting fibril-like morphology, is utilized as a third component in organic photovoltaic devices (OPVs). A power conversion efficiency (PCE) of 19% is achieved in ternary PM6:BTP-eC9:isoIDITC bulk-heterojunction (BHJ) devices. Analyses reveal the formation of an alloy model (BTP-eC9:isoIDTIC) and a well-defined fibril-like network and enhanced crystallization of BHJ in the ternary blend. Slightly increased carrier mobilities, longer carrier lifetimes, and suppressed trap-assisted/bimolecular recombination are observed in the ternary BHJ-based devices compared to the binary PM6:BTP-eC9 BHJ cells. Moreover, because of the high surface energy (γ) and low glass-transition temperature (Tg) of BTP-eC9, the acceptor and donor tend to migrate toward the hole and electron collecting electrodes, respectively, during aging tests. Crucially, isoIDTIC with low γ and high Tg has a low diffusion coefficient and can suppress demixing in vertical stratification of the BHJ, resulting in an increase in T80 lifetime from 101 hours to 254 hours. Our results highlight the utilization of the nonfullerene acceptor with fibril-like morphology and high Tg as an important third component toward high-performance and stable ternary OPVs.
Bibliographical noteFunding Information:
This research was funded in part, by the European Union's Horizon 2020 research and innovation programme under grant agreement no. 952911, project BOOSTER, grant agreement no. 862474, project RoLA-FLEX, and grant agreement no. 101007084 CITYSOLAR, as well as the EPSRC Project EP/T026219/1 EP/W017091/1. T. D. A. and Y. L. acknowledge the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Awards No. OSR-2018-CARF/CCF-3079 and OSR-2019-CRG8-4095. H. C. was supported by the open research fund of Songshan Lake Materials Laboratory 2022SLABFN06. Y. Z., S. B., and S. R. M. acknowledge funding from the Department of the Navy, Office of Naval Research as part of a Multidisciplinary University Research Initiative, Award No., N00014-21-1-2180. H. Y. W. acknowledges the financial support from the National Research Foundation (NRF) of Korea (2019R1A6A1A11044070).
© 2023 The Royal Society of Chemistry.
ASJC Scopus subject areas
- Environmental Chemistry
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering