Samples of (Sr 1.9Àx Ba x)SiO 4 :Eu 0.1 were synthesized by a solid-state reaction. The maximum emission intensity under 460 nm excitation was obtained at a Ba content, x, of 1.6. All Sr 1.9Àx Ba x SiO 4 :Eu 0.1 samples except for Ba 1.9 SiO 4 :Eu 0.1 exhibited a temperature-driven blue-shift of the emission band. The thermostability of emission in (Sr 1.9Àx Ba x)SiO 4 :Eu 0.1 depended strongly on the Ba/Sr ratio. The thermal quenching temperature reached its maximum at a Ba concentration x of 1.2-1.6 and was much lower for Ba 1.9 SiO 4 :Eu 2þ 0.1 .

This study reported the photoluminescence (PL) of gold nanoparticles (GNPs) doped planar nematic liquid crystals (NLCs) and observed around 64% enhancement in PL intensity with suitable doping amounts of GNPs in liquid crystals 5CB. The enhancement in PL intensity has been attributed to the increased surface area from GNPs, which results in increased emissions due to the increased scattering of excitation. The subsequent decay of PL intensity with doping more amounts of GNPs in liquid crystals 5CB was due to the aggregation of the GNPs, which resulted in decayed emissions due to the decay of the scattering of excitation. The concentration and the size of GNPs, as well as the orientation of the LCs’ director, with respect to the excitation, which depend on the intensity of the PL, were also investigated.

This research applies the non-linear effect of azo dye-doped liquid crystal materials to develop a small, simple, and adjustable beam-splitting component with grating-like electrodes. Due to the dielectric anisotropy and optical birefringence of nematic liquid crystals, the director of the liquid crystal molecules can be reoriented by applying external electric fields, causing a periodic distribution of refractive indices and resulting in a diffraction phenomenon when a linearly polarized light is introduced. The study also discusses the difference in the refractive index (Δn), the concentration of azo dye, and the rising constant depending on the diffraction signals. The experimental results show that first-order diffraction efficiency can reach ~18% with 0.5 wt % azo dye (DR-1) doped in the nematic liquid crystals.