Solid State Thiazole-Based Fluorophores: Promising Materials for White Organic Light Emitting Devices

Abstract A facile and more efficient solvent-free mechanochemical synthetic route has been developed for the synthesis of a series of solid state white light emissive thiazole-based donor-acceptor (D-A) type fluorophores, 2-(3-pyridyl)/2-aminothiazoles from u-bromomethylketones and pyridine-3-carbothioamide/thiourea in the presence of silica-supported HClO4 as a reusable solid Bronsted acid catalyst at room temperature. The photophysical and electrochemical properties of these compounds have been derived. Most of the studied D-A type solid thiazole-based fluorophores emitted white light and it can be tuned from warm - ideal - cold white light by the introduction of a variety of substituents at 4th position of 2-(3-pyridyl)/2-aminothiazoles. Further, HOMO and LUMO energy levels of the titled compounds are found to be in the range -5.52 eV to -5.72 eV and -1.84 eV to -2.45 eV, respectively. The lifetimes of these levels of thiazole-based fluorophores have been determined through luminescence decay curves and are found to be in the range of 7.7 – 11 μs. The photophysical and electrochemical properties of the synthesized thiazole-based fluorophores indicate that the compounds could be promising materials for white organic light emitting devices.