Perylene bisimide J-aggregates in polymer matrix: controlling self-assembly and fluorescence properties

Abstract

Perylene bisimide J-aggregates are among the most emissive dye aggregates. However, their fluorescence quantum yield severely decreases if casted as pristine materials in solid films. Here we present an approach to prepare solid-state materials containing fluorescent perylene bisimide (PBI) J-aggregates with fluorescence quantum yields up to 28%, which is significantly higher than in their single-crystalline state. In our research we investigated the impact of different polymer matrices, i.e. polystyrene, poly(methyl methacrylate) and a polystyrene-polybutadiene-polystyrene triblock copolymer, on the self-assembly into J-aggregates and the fluorescence quantum yield of the dye-matrix materials for spin-coated films. The degree of self-assembly of PBIs could be controlled by the PBI concentration, the type of polymer matrix, and an annealing process after spin-coating. Notably, the J-aggregates in a polystyrene matrix showed significant differences in their fluorescence quantum yield, which we attribute to transitions between individual one-dimensional fibers and the formation of larger three-dimensional crystallites.