Utilization of Co2+ doped Eu2O3 nanostructures and their effect on the dielectric and photoisomerization of liquid crystals

Abstract

In this study, the effect of Co2+x:Eu2O3 (x = 5, 10 wt. %) bimetallic oxide nanostructures (NS) on dielectric and cis-trans photoisomerization of liquid crystals (LC) has been studied. First, the Co2+:Eu2O3 NS were synthesized by facile coprecipitation method, and then the as-synthesized NS were characterized by x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, Brunauer Emmett Teller, and UV-visible analytical techniques. New composite structures were prepared by doping Co2+:Eu2O3 (5, 10 wt. %) over liquid crystal (LC) molecules (compounds 4 and 5) containing oxazole moiety. Optical absorption spectra of liquid crystalline NS (LCNS) showed a maximum absorption peak (λmax) between 350 and 450 nm. A significant improvement in the dielectric constants (ɛ′ and ɛ″) was noticed for LC-4 (compound 4)/LC-5 (compound 5) doped with Co2+ (10 wt. %):Eu2O3 NS. The photoisomerization studies of the Co2+ (10 wt. %):Eu2O3 doped to LC-5 (LCNS-2) containing oxazole moiety showed enhanced properties in solution and exhibited photoisomerization in 40 s whereas reverse process (thermal back relaxation) takes 358 s. Furthermore, it was observed that semiconductor NS especially Co2+ (10 wt. %):Eu2O3 NS doped LC-compounds showed enhanced dielectric and photoisomerization properties and can be a potential candidate for optoelectronics and photonic applications.