EXCITON MANAGEMENT IN METALLOPORPHYRINS AND THIAZOLOTHIAZOLE-BASED MATERIALS

Over the last few decades, optical technologies utilizing organic materials in the solid state have become ubiquitous. In the solid state, contrary to their constituent molecules, organic materials exhibit energy level continuums along which excited-state energy (excitons) can diffuse. Controlled and efficient management of excitons in systems with numerous organic molecules packed in limited degrees of freedom has been the governing principle for organic optoelectronic devices. However, given the net neutral electrical charge of an exciton and the complex excited-state energy landscape in organic molecular aggregates, efficient management of excitons becomes a challenging task.
In this lecture I will present three significant studies that explore the manipulation of exciton behavior in organic solid-state materials through self-assembly techniques. By modulating molecular packing in the solid state, the energetics and photophysical properties of the chromophores can be effectively controlled, opening up avenues for advanced optical and photonic applications. The successful modulation of exciton diffusion in Zn-metalloporphyrin solution-processable thin films and the establishment of a structure-photophysics correlation in disubstituted alkoxyphenyl thiazolo[5,4-d]thiazole (TTz)-based crystals demonstrate the potential of this approach. Furthermore, the controlled formation and relaxation kinetics of excimers in asymmetric TTz films offer a novel route to achieving high luminescence efficiency, paving the way for a new generation of optical and photonic devices. These findings highlight the importance of self-assembly as a powerful tool for tailoring the behavior of excitons in organic chromophores, leading to significant advancements in various fields.