Volatilizable and cost-effective quinone-based solid additives for improving photovoltaic performance and morphological stability in non-fullerene polymer solar cells

Abstract

Controlling the morphological stability of non-fullerene polymer solar cells (NF-PSCs) is a critical process for improving photovoltaic performances. In many systems, liquid additives have been widely used to produce favorable morphological features; however, liquid additives frequently leave residues after thermal treatment owing to their high boiling points, which has detrimental effects on the reproducibility of NF-PSCs. In this study, commercially available and volatilizable solid additives, 9,10-anthracenedione (BDT-1) and benzo[1,2-b:4,5-b′]dithiophene-4,8-dione (BDT-2), are selected to coordinate the molecular arrangement to enhance absorption intensity, charge transfer, and molecular crystallinity. Suppressed bimolecular recombination and a favorable balance between the domain size and relative domain purity were observed with the introduction of both solid additives, which improved the photovoltaic parameters of NF-PSCs. PM6:TPT10-based devices with BDT-1 and BDT-2 additives achieved the best power conversion efficiencies (PCEs) of 16.26% and 15.18%, respectively, which were better than the 13.55% achieved with a 1,8-diiodooctane (DIO) additive. Other NF-PSC systems of PBDB-T:TPT10 and PTQ10:TPT10 blends also showed that the photovoltaic performance with the solid additives is superior to that with liquid additives. These results imply that the use of solid additives is a promising strategy to improve the PCEs of NF-PSCs.