Optical Properties and Electronic Structures of a Liquid Crystal TBO10A

Abstract

A liquid crystal (LC) N,N-(terephthalylidene) bis (4-octyloxyaniline) (TBO10A) was synthesized at room temperature. The LC TBO10A were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), ultraviolet-visible spectrophotometry, photoluminecence (PL) spectroscopy and electronic structure calculations. In tetrahydrofuran solutions, two optical absorption bands were recorded for TBO10A at about 298 and 379 nm, respectively. Under the 325 nm excitation, dilute tetrahydrofuran solutions of the TBO10A can give off weak blue PL. With Hückel tight-binding method, the electronic structures of the TBO10A were calculated. Our results demonstrated that two absorptions can be attributed to theπ→π* andn→π* transitions in the rigid core of the TBO10A while the PL observed at about 481 nm (2.58 eV) can be assigned to theπ* →ntransition.