光电转换率超过12%的含氯非富勒烯受体基有机光伏器件

A new chlorinated non-fullerene acceptor based organic photovoltaic cells over 12%efficiency

末端基团的氟化能显著改善有机受体材料的光电性能并已实现了广泛的应用。相比之下,氯化策略被关注得较少且对有机光伏电池的影响仍不明确。这里,我们报道了一个以苯并三唑为缺电子核及2Cl-IC为末端基团的新型非富勒烯受体Y19。Y19表现了优异的光学及电化学性质。Y19的薄膜吸收边带为948 nm,LUMO能级水平为−3.95 eV。基于PM6:Y19的光伏器件实现了12.76%的能量转换效率,其开路电压为0.84 V,短路电流密度为22.38 mA/cm2,填充因子为0.68。优化后的活性层有理想的形貌并且电子迁移率达到6.52×10−4 cm2/(V·s)。EQE测试表明外部量子效率在480~860 nm的范围内超过了60%。这一研究表明氯化作为一种低成本的分子设计策略在一定程度上也能改善光伏性能。

The method to fluorinate the terminal group has achieved remarkable success and been widely used to fine-tune the intrinsic properties of organic acceptor materials.Referring to chlorination,however,it gets less attention and remains ambiguous effect on organic photovoltaic(OPV)cells.Herein,a new non-fullerene acceptor named Y19 was reported with benzotriazole as the electron-deficient core and 2Cl-ICs as the strong electron-withdrawing end groups.Y19 exhibits a wide film absorption band from 600 nm to 948 nm and low LUMO(the lowest unoccupied molecular orbital)energy level of−3.95 eV.Photovoltaic devices based on PM6:Y19 show high-power conversion efficiency(PCE)of 12.76%with high open-circuit voltage(Voc)of 0.84 V,short-circuit current density(Jsc)of 22.38 mA/cm2 and fill factor(FF)of 68.18%.Broad external quantum efficiency(EQE)response of over 60%in the range of 480−860 nm can be obtained.This study demonstrates that chlorination,as a low-cost molecular design strategy,has its own superiorities to improve device performance and promote the potential application in OPV.