Boosting the photovoltaic performance of doctor-bladed organic solar cells using a low-boiling solvent additive

Organic solar cells (OSCs) are attracting much attention due to their distinct benefits of low cost, lightweight and mechanical flexibility. Low-cost and high-throughput approaches combined with large-scale and roll-to-roll (R2R) processes for producing efficient OSCs in ambient condition will considerably speed up the potential commercialization of OSCs. Herein, the low-boiling additive 1,4-difluorobenzene (1,4-DFB) is proposed to produce high-quality PM6:Y6:PC61BM blend active layer dissolved in low-boiling solvent via the doctor blading process in ambient condition. The additive 1,4-DFB can improve the morphology, 7c-7c stacking and phase separation, decrease the charge recombination and produce the red-shift absorption, leading to the enhanced carrier mobility and more balanced charge transport. Thus, it boosts the performance parameters with obviously enhanced short-circuit current and fill factor, and a power conversion efficiency of 15.34% is achieved. Meanwhile, the OSCs with the 1,4-DFB additive treatment also exhibit much better stability. The results demonstrate that low-boiling additive engineering with 1,4-DFB is a powerful route to improve the performance of OSCs prepared by doctor-blading in ambient condition.