Enhancing efficiency in organic electronics via J-aggregation modulation with non-halogenated solvents

Abstract

Aggregation of the donor and acceptor is crucial for determining the phase separation in the active layer, which constrains the performance of organic optoelectronics. Herein, we focused on the molecular aggregation modulation in the active layer comprising PM6:GS-ISO, which was processed using non-halogenated solvents. The findings reveal that employing o-xylene (O-XY) as a solvent predominantly modulates the J-aggregation of the acceptor. Using 1,8-diiodooctane (DIO) as the processing additive, we can effectively adjust the donor's J-aggregation, optimizing phase separation and improving molecular ordering. Remarkably, a precise phase segregation and optimized donor–acceptor distribution effectively minimized trap-assisted recombination and substantially enhanced charge collection efficiency. Finally, organic solar cells (OSCs) processed with DIO achieved a power conversion efficiency (PCE) of 26.56% under indoor light, while organic photodetectors (OPDs) attained an impressive specific detectivity of 7 × 10¹² cm Hz^1/2 W⁻¹. Our results offer valuable insights into modulating phase separation using a co-aggregation strategy for high-performance organic photovoltaics.