V. Reddy Prasad

Luminescence performance of Eu3+-doped lead-free zinc phosphate glasses for red emission

In this study, the luminescence performance of zinc phosphate glasses containing Eu3+ ion with the chemical compositions (60–x)NH4H2PO4-20ZnO-10BaF2-10NaF–x Eu2O3 (where x = 0.2, 0.5, 1.0 and 1.5 mol%) has been studied. These glasses were characterized by several spectroscopic techniques at room temperature. All the glasses showed relatively broad fluorescence excitation and luminescence spectra. Luminescence spectra of these glasses exhibit characteristic emission of Eu3+ ion with an intense and most prominent red emission (614 nm), which is attributed to 5D0 → 7F2 transition. Judd-Ofelt (Ω2, Ω4) parameters have been evaluated from the luminescence intensity ratios of 5D0 → 7FJ (where J = 2 and 4) to 5D0 → 7F1 transition. Using J-O parameters and excitation spectra, the radiative parameters are calculated for different Eu3+-doped glasses. Effect of γ-irradiation at fixed dose has been studied for all the Eu3+-doped glass matrices. The lifetimes of the excited level, 5D0, have been measured experimentally through decay profiles. The colour chromaticity coordinates are calculated and represented in the chromaticity diagram for Eu3+-doped zinc phosphate glasses for all concentrations.

Impact of Bi2O3 on structural properties and lasing effects in Nd3 + doped bismuth phosphate glasses at 1.053 μm emission

Influence of addition of bismuth oxide (Bi2O3) on structural and optical properties of 0.5Nd3+doped different phosphate glasses prepared by melt quenching technique were reported. The structural properties were analysed by FT-IR and 31P MAS NMR techniques. 31P NMR results showed that, with the variation of Bi2O3 concentration in the prepared phosphate glass matrices there was no significant change in the structure. The optical properties have been analysed using Judd-Ofelt (J-O) theory. From absorption spectra, three phenomenological J-O intensity parameters (Ω2, Ω4, Ω6) have been calculated and these parameters were used to estimate the radiative properties. The J-O intensity parameters increased with increase in the concentration of Bi2O3, which confirmed the higher covalency, asymmetry and rigidity. The branching ratios (β) and emission cross-sections (σ) were calculated from the emission spectra of Nd3+ doped bismuth phosphate (BiP) glasses. Among different glass matrices 15mol% of Bi2O3 glass matrix has higher β and σ values which are useful for the laser applications. The improved emission cross-section value with the addition of Bi2O3 content results low threshold and high gain applications. The decay curves of all these BiP glasses showed single exponential behaviour.

Luminescence performance of Eu3+ doped lead free zinc phosphate glasses for red emission

In this study, the luminescence performance of zinc phosphate glasses containing Eu3+ ion with the chemical compositions (60–x)NH4H2PO4-20ZnO-10BaF2-10NaF–x Eu2O3 (where x = 0.2, 0.5, 1.0 and 1.5 mol%) has been studied. These glasses were characterized by several spectroscopic techniques at room temperature. All the glasses showed relatively broad fluorescence excitation and luminescence spectra. Luminescence spectra of these glasses exhibit characteristic emission of Eu3+ ion with an intense and most prominent red emission (614 nm), which is attributed to 5D0 → 7F2 transition. Judd-Ofelt (Ω2, Ω4) parameters have been evaluated from the luminescence intensity ratios of 5D0 → 7FJ (where J = 2 and 4) to 5D0 → 7F1 transition. Using J-O parameters and excitation spectra, the radiative parameters are calculated for different Eu3+-doped glasses. Effect of γ-irradiation at fixed dose has been studied for all the Eu3+-doped glass matrices. The lifetimes of the excited level, 5D0, have been measured experimentally through decay profiles. The colour chromaticity coordinates are calculated and represented in the chromaticity diagram for Eu3+-doped zinc phosphate glasses for all concentrations.