Luminescent hybrid materials based on emissive molecules incorporated in inorganic hosts

Abstract

Luminescent hybrid materials based on inorganic hosts incorporated with emissive molecular species as lanthanide and/or transition metal complexes and organic dyes have attracted much current interest for medical, biological and technological applications (lasers, sensors, waveguides, OLEDs, etc). The performance of these materials is directly influenced by the incorporation efficiency and the distribution of the emissive species in the hosts, by their stability upon exposure to external ambient and by the chemical environment in which they are inserted. Thus, besides the optimization of the obtention procedures and detailed photophysical characterization of the final materials and their precursors, it is important to understand their structural characteristics and correlate them to properties. In this sense, our study proposal is quite encompassing since only in this way one can expect to acquire a comprehensive understanding of the materials from the scientific point of view, while bearing the applications in mind. This research project, in particular, is focused on the obtention and conventional and spectroscopic (optical and by solid state NMR/EPR) studies, of mesoporous silica or organosilica hosts incorporated with lanthanide (Eu3+, Tb3+, Nd3+, Er3+, Yb3+) and transition metal (Ir3+) complexes, and organic dyes (Rh6G). Employing the sol-gel methodology, several approaches are used to immobilize the luminescent species in the pores of the hosts. Besides the photophysical characterization, which includes determination of quantum yields and calculations of electronic structures and energy transfer processes, high resolution solid state NMR techniques are employed to investigate the host formation before and after inclusion of the guest molecules, the host-guest binding character and the quantification of the active guest species. (AU)