Perylene imide derivatives: Structural modification of imide position, aggregation caused quenching mechanism, light-conversion quality and photostability

To explore highly efficient yellow-green light conversion agents and the intrinsic mechanism of aggregation caused quenching of perylene imide derivatives, three perylene imide derivatives named as PDI-1, PDI-2 and PDI-3 were designed and synthesized, and their polyvinyl chloride, polybutylene adipate-polybutylece terephthalate (PBAT) copolymer and different ethylene-vinyl alcohol copolymers doping films were prepared. The perylene imide derivatives present similar solvatochromism in various solvents and fluorescence quenching in aggregated state, and then the intrinsic mechanism of fluorescence quenching was investigated by viscosity experiment, theoretical calculation and crystal analysis. Subsequently, light conversion quality of different doping films was measured and evaluated by using a HiPoint HR-450 analyzer in the range of 380–780 nm. Finally, photostability of the doping films was investigated by intensified ultraviolet light radiation (40 W). The results show that fluorescence quenching of the perylene imide derivatives has nothing to do with π-π stacking, which are attributed to twisted intramolecular charge transfer (PDI-2) and rotation and vibration of molecular bonds (PDI-1 and PDI-3). After UV radiation of 30 h, emission intensities of 25%[email protected] and 40%[email protected] fluctuate only slightly. From this, a simple and efficient way to enhance photostability was obtained by choosing amphipathic EVA copolymers.