Photo-physical and semi-empirical studies of a dominant blue light emitting 1,4-dibenzthiazolyl benzene

Abstract

A featured blue light emitting electron transport material 1,4-dibenzthiazolyl benzene (BTH) shows a structured emission with peak maxima at 440 nm (full width half maxima of ∼100 nm) with a shoulder at 530 nm. Pronounced PL emission from the localized and delocalized excited states gives a broad emission spectra. Semi-empirical AM1-CI Hamiltonian method suggests that the electron density in LUMO+2 and LUMO+3 states are more localized at the benzthiazole rings leading to a predominant 440 nm peak, while the electron charge is more delocalized in the LUMO and LUMO+1 states, similar to HOMO level, which accounts for the 530 nm peak. The thermo-gravimetric study shows a ∼100% weight loss between 275 and 350 °C that corresponds to melting followed by decomposition. Cyclic voltammogram shows fully reversible reduction waves at −0.95 and −1.35 V, which corresponds to two one-electron transfer steps indicating the ability of the molecule to undergo reduction easily, making it an excellent electron transport material.