In organic photovoltaics, morphological control of donor and acceptor domains on the nanoscale is the key for enabling efficient exciton diffusion and dissociation, carrier transport and suppression of recombination losses. To realize this, here, we demonstrated a double-fibril network based on a ternary donor–acceptor morphology with multi-length scales constructed by combining ancillary conjugated polymer crystallizers and a non-fullerene acceptor filament assembly. Using this approach, we achieved an average power conversion efficiency of 19.3% (certified 19.2%). The success lies in the good match between the photoelectric parameters and the morphological characteristic lengths, which utilizes the excitons and free charges efficiently. This strategy leads to an enhanced exciton diffusion length and a reduced recombination rate, hence minimizing photon-to-electron losses in the ternary devices as compared to their binary counterparts. The double-fibril network morphology strategy minimizes losses and maximizes the power output, offering the possibility of 20% power conversion efficiencies in single-junction organic photovoltaics.
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This work was financially supported by the National Natural Science Foundation of China (grant nos 51973110, 21734009, 21905102, 51825301, 21734001 and 22109094), the National Key R&D Program of China (grant nos 2020YFB1505500 and 2020YFB1505502), the Program of Shanghai Science and Technology Commission’s Science and Technology Innovation Action Plan (grant nos 20ZR1426200, 20511103800, 20511103802 and 20511103803), the Natural Science Foundation of Shandong Province (grant no. ZR2019LFG005), the Key Research Project of Shandong Province (grant no. 2020CXGC010403) and the Center of Hydrogen Science, Shanghai Jiao Tong University, China. J.N. and J.Y. thank the European Research Council for support under the European Union’s Horizon 2020 research and innovation programme (grant nos 742708 and 648901). We thank C. Wang and C. Zhu from the Advanced Light Source for providing X-ray scattering tests, which were carried out at beamlines 7.3.3 and 22.214.171.124 at the Advanced Light Source, Molecular Foundry, Lawrence Berkeley National Laboratory, supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.
The authors declare no competing interests.
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Zhu, L., Zhang, M., Xu, J. et al. Single-junction organic solar cells with over 19% efficiency enabled by a refined double-fibril network morphology. Nat. Mater. 21, 656–663 (2022). https://doi.org/10.1038/s41563-022-01244-y
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