Luminescence mechanisms in the 2V2O5-xLi2O-(98-x)B2O3 glass matrices developed for creation of efficient glass-ceramic materials

Abstract

The oxide glass-ceramics are promising class of solid state materials because they are using thermally stable and chemically inert glass oxide matrices. Development of such efficient glass matrices suitable for creation of glass-ceramic materials for several purposes is an important practical task. The xLi2O-yV2O5-(100-x-y)B2O3 undoped glass and 47Li2O-2V2O5-50B2O3-1La0.3Eu0.7VO4 glass samples with crystalline nanoinclusions were synthesized and investigated using XRD, IR and UV-Vis spectroscopy and UV band-to-band excitation of luminescence. The synthesized glass samples are characterized by wide band photoluminescence emission with maximum at 570 nm and intensity increased with increase of Li2O concentration. The excitation spectra consist of three bands with maxima positions at 270, 320 and 365 nm. The observed concentration dependencies of spectral distributions in the absorption and excitation spectra are explained by influence of the lithium ions on a ratio between triborate and tetraborate groups in the glass networks. The assumption is made that the observed wide band photoluminescence emission of the glass matrix can appear as a result of recombination processes between the defects in borate networks and the broken vanadate groups. The crystalline component in the doped glass samples is found to not affect the luminescence properties of the glass matrix. Intensity of narrow band photoluminescence emission of the crystalline component is up to 10 times more intense than that of the glass matrix wide band emission. The synthesized type of the glass matrices has promising characteristics for the use of developed materials in lighting devices, as it allows improving the spectral distribution of light emission towards the white light.