Boosts charge utilization and enables high performance organic solar cells by marco- and micro- synergistic method

A ternary solar cell is a typical strategy that can well compensate light absorption and effectively regulate energy levels and the morphology of active layers. However, the commonly used active materials have low relative dielectric constant, which is one of the important limitations for improving the photovoltaic performance of organic solar cells (OSCs). In this work, an insulating polymer MPFM with high relative dielectric constant is introduced into the ternary active layers to improve the performance of OSCs by synergistic effect of macro light utilization and micro interface modulation. The introduction of MPFM not only strengthened the dielectric constant of bulk heterojunctions but also enhanced the degree of crystallinity and adhesivity, promoted the exciton separation, suppressed charge recombination, and significantly accelerated charge transport. As a result with the addition of MPFM, an outstanding efficiencies of 18.21% and 18.53% are achieved for devices based on PM6:Y6:PC71BM and PM6:BTP-eC9:PC71BM, respectively. These results indicated that constructing the micro-PIN junction by using MPFM is an effective strategy to further improve the photovoltaic performance of OSCs.