Luminescence properties of Eu3+-doped potassium-gadolinium-phosphate glasses

Eu2O3-doped K2O-Gd2O3-P2O5 glasses were fabricated using the melt-quenching technique. The result indicates that the glasses' density and refractive index increase while the molar volume decreases from 0.05 to 0.5 mol% and then increases from 0.5 to 2 mol% with increased Eu2O3 concentration. The absorption spectra in the UV-Vis and NIR regions exhibit an energy transition from a ground state to possible excited states for 7F0 → 5K5, 7F0 → 3P0, 7F1 → 5G2, 7F0 → 5L6, 7F1 → 5D3, 7F0 → 5D2, 7F1 → 5D1 and 7F0 → 7F6, and 7F1 → 7F6. The luminescence characteristics were examined by photoluminescence (PL) and radioluminescence (RL). Both PL and RL confirmed that the optimum value at 2 mol% of Eu2O3 concentration. Similarly, the luminescence efficiency of 2 mol% Eu2O3 concentration compared with the BGO crystal equals 16.77%. As the concentration of Eu2O3 increased, the experimental decay curve dropped while the energy transfers efficiency (ɳET) and the energy transfer parameter (Q) raised. Interestingly, the CIE of emission spectra under 393 nm (UV lamp) were reddish orange (0.64, 0.35). The branching ratio (βR) was most significant at 612 nm, and the JO parameter trend was Ω2 > Ω6 > Ω4. Furthermore, all characterizations confirm its applicability in optical display devices.