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Molecular Order Control of Non-fullerene Acceptors for High-Efficiency Polymer Solar Cells

2018; Elsevier BV; Volume: 3; Issue: 3 Linguagem: Inglês

10.1016/j.joule.2018.11.023

2542-4785

Wei Li, Mengxue Chen, Jinlong Cai, Emma L. K. Spooner, Huijun Zhang, Robert S. Gurney, Dan Liu, Zuo Xiao, David G. Lidzey, Liming Ding, Tao Wang,

Perovskite Materials and Applications

Adjusting molecular ordering, orientation, and nanoscale morphology within the photoactive layer of polymer:non-fullerene organic solar cells is crucial in achieving high power-conversion efficiency (PCE). Herein, we demonstrate that the molecular ordering and orientation of the n-type small-molecule acceptor COi8DFIC can be tuned from flat-on and edge-on lamellar crystalline to H- and J-type π-π stacking during the solution-casting process, resulting in broadened photon absorption and fine phase separation with the electron donor PTB7-Th. This favorable morphology with face-on π-π stacked electron donors and acceptors promotes efficient exciton dissociation at the donor/acceptor interface, together with enhanced and balanced carrier mobility. The enhanced short-circuit current density and fill factor lead to the achievement of a maximum PCE of 13.8% in binary, single-junction PTB7-Th:COi8DFIC non-fullerene polymer solar cells while also exhibiting superior stability.