Influence of Bi3+ ions on optical and luminescence properties of multi- component P2O5─PbO─Ga2O3 ─Pr2O3 glass system

Abstract Glasses with composition (70-x) P2O5─17.5PbO ─10Ga2O3─2.5Pr2O3:xBi2O3 (0 ≤ x ≤ 7) were prepared by conventional melt quenching technique. The prepared glasses were characterized by their XRD patterns. Various spectroscopic studies like FTIR, optical absorption and photoluminescence were carried out on these glasses. The optical absorption spectra exhibited eight absorption bands around 444, 468, 481, 590, 1012, 1424, 1528 and 1941 nm wavelengths corresponding to transitions 3H4 →3P2,3P1, 3P0, 1D2, 1G4, 3F4,3F3 and 3F2 respectively. In addition to the above, the optical absorption spectra have also exhibited additional band at about 444 nm due to the addition of Bi2O3 to the host glass and is ascribed to the 1S0 →3P1 transition of Bi3+ ions. J-O intensity parameters computed from the absorption spectra of the samples by using modified J-O theory exhibited the order Ω2> Ω6> Ω4. Emission spectra of the prepared glasses were recorded at excitation wavelength 444 nm. The luminescence intensity of Pr3+ ions is found to increase with an increase in the concentration of Bi2O3 up to 5 mol% beyond this concentration decreasing trend in it is noticed. Such observed hike in the intensity of luminescence of Pr3+ ions might be due to the occurrence of energy transfer between Pr3+ and Bi3+ ions. Chromaticity color coordinates for all the glass samples were evaluated. Decay curves of all the glass samples exhibit double exponential behavior. Significant energy transfer parameters viz., the luminescence quantum efficiency (ɳQ), energy transfer efficiency (ɳET), energy transfer parameter (Q), energy transfer probability (PDA) and critical transfer parameter (R0) were evaluated for all the titled glasses by using the life time values. From the investigated spectroscopic studies and evaluated energy transfer parameter values it can be seen that the glass sample mixed with 5 mol% of Bi2O3 is a good host that can emit bright reddish - orange laser.