Energy gap 2 UV–Vis spectroscopy Borate glasses 1 Chlorine compounds 1 Crystal structure 1 DFT 1 Density functional theory 1 Density-functional-theory 1 Dielectric devices 1 Dielectric interference filters 1 Dielectric resonator filters 1 Double Perovskites 1 Double perovskites 1 Electronic properties 1 Emission bands 1 Emission properties 1 Erbium compounds 1 Erbium-vanadium doped glasses 1 Excitons 1 Fourier transform infrared spectroscopy 1 Glass 1 Glass samples 1 Light absorption 1 Lower energies 1 MBJ 1 Melt quenching method 1 Metal nanoparticles 1 Optical correlation 1 Optical emission spectroscopy 1 Optical fibers 1