2021 Energy Environ. Sci. (IF 38.532): The strategy of choosing the appropriate third component in the ternary OSC

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　　Energy & Environmental Science (IF 38.532) recently published a study. Organic solar cells (OSCs) are considered to be a promising solar energy conversion technology due to their unique advantages of low cost, light weight and ease of fabrication. Using a ternary OSC containing two donors/one acceptor or one donor/two acceptors is an effective method to improve the power conversion efficiency (PCE) of the device. However, few people pay attention to how to choose the appropriate third component. This article proposes a strategy for selecting the third component in non-fullerene acceptor-based ternary OSCs.

　　By using the same central unit with the host receptor and a single fluorinated end group, the designed non-fullerene receptor can be successfully used as the third component of the ternary OSCs. Following this principle, the authors synthesized three non-fullerene acceptors BTP-F, Y6-F and L8-BO-F, and they were applied to PM6:BTP-eC9, PM6:Y6 and D18-Cl:L8-BO respectively as the third components to form ternary OSCs.

(e) J–V curves of the binary and ternary OSCs. (f) Histograms of the PCE values of the binary and ternary OSCs. (g) EQE spectra of the binary and ternary OSCs. The solid lines represent the integrated Jsc values of the binary and ternary devices.

　　Enlitech’s QE-R Quantum Efficiency Measurement system was used in this study to to characterize the OSCs. It was found that compared with binary devices, all t ternary devices have higher PCEs. Among them, the optimized PM6:BTP-eC9 ternary OSC showed a high PCE of 18.45%. Compared with the host system, it also shows excellent stability. It was also found that the introduction of BTP-F into the ternary blend increased charge transport, improved active-layer morphology and reduced non-radiative recombination, thereby simultaneously increasing short-circuit current, fill factor and open circuit voltage. These results not only provide a general strategy for how to choose the third-component design for ternary OSCs, but also provide a new way for the further development of high-performance OSCs.

　　The quantum efficiency measurement system is used for EQE (external quantum efficiency) spectral analysis of perovskite solar cells. It also provides a comparison of Jsc (short-circuit current density) for the short-circuit current of solar cells under sunlight to prove the experimental results.