Concentration dependent Dy3+- doped lithium fluoro borotellurophosphate glasses’ structural and optical investigations for white light emission under UV excitation for solid-state lighting applications

Abstract

Concentration dependent Dy3+ - doped lithium fluoro borotellurophosphate glasses were prepared by conventional melt quenching technique by varying the dopant concentration (0.1, 0.25, 0.5, 1.0 & 1.5 wt %). The structural and compositional analyses have been carried out through XRD, FTIR, SEM and EDAX respectively. The optical studies were made to analysis the optical behavior of the Dy3+ ions in the synthesized glasses through absorption and emission spectra. The nephelauxetic ratio and bonding parameter were calculated from the absorption spectra. The oscillator strength fexp and fcal along with σrms were evaluated and reported. The JO intensity parameters (Ω2, Ω4 and Ω6) have been calculated and trends reported. The photoluminescence spectra were recorded under 384 nm excitation. The radiative properties like emission band position (λp), effective bandwidth (Δλeff), radiative transition probability (A), stimulated emission cross-section (σpE), calculated and experimental branching ratios (βR) for the Dy3+-doped lithium fluoro borotellurophosphate glasses were calculated using JO intensity parameters and emission data. The CIE color coordinates (x,y) and Y/B ratio values were calculated from the photoluminescence spectra. The color correlated temperature (CCT) were determined from the (x,y) values and possibility for white light emissions from the synthesized glasses were analyzed under UV excitation. The decay analysis shows the non-exponential behavior of the present glasses.