Controllable intramolecular interaction of 3D arranged π-conjugated luminophores based on a POSS scaffold, leading to highly thermally-stable and emissive materials

Abstract

This manuscript describes the inorganic cubic core as an advantageous scaffold for realizing solid-state emissive materials with high thermal stability. Polyhedral oligomeric silsesquinoxane (POSS) materials having π-conjugated luminophores connected to eight vertices of the POSS core were prepared. In a dilute solution, the π-conjugated luminophores around the POSS scaffold interacted with the neighboring π-conjugated luminophores, resulting in excimer formation. By introducing bulky alkyl chains into the luminophores, the intrinsic luminescent property of the monomer was recovered. In the solid state, interestingly, the π-conjugated luminophores linked to the POSS scaffold exhibited similar optical properties regardless of the existence of the bulky substituents. Emission bands with almost the same shapes in the spectra were obtained from the POSS materials. In addition, high thermal stabilities of the π-conjugated luminophores were detected. Finally, it was demonstrated that the POSS materials presented bright blue emission even beyond 200 °C in the open air. High thermal stabilities and solid-state emissive properties were realized owing to the cubic structure of the POSS core. A new versatile molecular scaffold for thermally-durable optical materials is offered.