Octadecylamine-capped CdSe/ZnS quantum dot dispersed cholesteric liquid crystal for potential display application: Investigation on photoluminescence and UV absorbance

Abstract

ABSTRACT In the present investigation, we have undertaken the photoluminescence and UV absorbance study of a newly synthesised cholesteric liquid crystal (CLC) and CLC– octadecylamine-capped CdSe/ZnS quantum dots (QDs) composites. Three different CLC–QDs composites are prepared by varying the concentration of QDs in CLC. The thermal behaviour of both the pure CLC as well as three different CLC–QDs composites are performed by using Polarising Optical Microscopic (POM) textural studies. The photoluminescence (PL) study indicates that the PL intensity increases after the dispersion of QDs into the pure CLC. Decrement in the FWHM parameter also supports this increased PL intensity. However, the UV absorbance decreases for the QD dispersed CLC system when compared to the pure CLC. Optical band gap (by the Tauc plot method) suggests that the observed band gap reduces after the dispersion of QDs into CLC. The outcome of these investigations may be useful in the liquid crystal displays (LCDs) and other opto-electronic devices, which require less band gap materials.