Highly ordered AIEgen directed silica hybrid mesostructures and their light-emitting behaviours

Abstract

Mesostructured fluorescent silica hybrids (MFSHs) were synthesized using tetraphenylethylene (TPE)-based quaternary ammonium salts as amphiphilic organic fluorophore templates, carboxyethylsilanetriol disodium salt (CES) as a co-structure directing agent (CSDA) and tetraethylorthosilicate (TEOS) as an inorganic precursor. With increasing alkyl chain length of the templates, the mesostructures transformed from a lamellar structure (alkyl carbon chains of C4, C5, C6 and C7) to three-dimensional (3D) bicontinuous cubic gyroid structures (C8 and C10). These materials show typical aggregation-induced emission (AIE) behaviours corresponding to the molecular arrangement in the mesoscale. Compared to the pure template, the emission maximum of the material with a lamellar structure shows a red-shift phenomenon due to the higher conjugation caused by the close stacking of the AIEgens, while the emission maximum remains unchanged in the bicontinuous cubic structure owing to the loose stacking of the template molecules.