Tunable excitation dynamics, fluorescence decay and microstructural analysis of Eu(2)O(3), Nb(2)O(5)nanoparticles doped birefringent liquid crystals.

In this investigation, liquid crystalline nanocomposite (LCNCs) of azobenzene derivatives(methyl 4-[()-(4-butoxy-2,5-difluorophenyl)diazenyl]-3-methoxybenzoate), and(methyl 4-{()-[2,5-difluoro-4-(hexyloxy)phenyl]diazenyl}-3-methoxybenzoate) were doped with 0.5 wt.% europium oxide (EuO), niobium oxide (NbO) nanoparticles (NPs) and named as@EuO,@NbOLCNCs. The powdered x-ray diffraction confirms the purity and integration of EuO, NbONPs. Field emission scanning electron microscope studies demonstrate a non-uniform worm/flake-like morphology with agglomeration of LCNCs. A slight shift in optical band gap was observed forLCNCs, and broad absorption bands were observed in ultraviolet-visible studies. The existence of birefringent textures of@EuOand@NbOLCNCs is confirmed using a polarizing optical microscope. Room temperature photoluminescence (PL) studies demonstrate pronounced luminescence maxima with sharp emission peaks of violet, blue, green emissions under excitation at 380 nm, 460 nm, 360 nm, and 375 nm. Steady state PL (SSPL) of@EuOLCNC exhibits luminescence maxima associated with vibrant red, blue, and greenish-yellow colors, while SSPL of@NbOLCNC shows emission peaks of brilliant blue, yellow, green, orange, red colors at various. Furthermore, the large Stokes shift and full width at half maximum of@EuOand@NbOLCNCs are attributed to the presence of additional/virtual energy levels during the photoexcitation process. The fluorescence decay studies of@EuOLCNC display average lifetime dwell between 19.8 ns and 0.276 ns, while@NbOexhibits 9.69 ns to 10.20 ns, at various excitation wavelengths. The quantum yield varies between -7.77 × 10% to 5.23 × 10% and 0.86% to 0.14% for@EuOand@NbOLCNCs, respectively, upon increase in. Polarization studies of@EuOLCNC atangle (0°) showed intense defect-centered blue, red emission bands (445 nm, 613.8 nm) attributed to the excited state virtual orbitals that undergo non-radiative decay with higher energy content. Thus, the results obtained for synthesizedLCs doped with EuOand NbONPs make these usable for advanced optoelectronics, photonic, fluorescence/photo-luminescence device applications.