Structural and spectroscopic investigations of multi–component P2O5─PbO ─Ga2O3─Dy2O3─Bi2O3 glass system: An insight to the energy transfer between Bi3+ and Dy3+ ions

Abstract

P2O5─PbO─ Ga2O3─Dy2O3 glasses doped with different concentrations of Bi2O3were prepared by conventional melt quenching technique. The prepared glasses were characterized by optical absorption and luminescence studies. The observed decreasing trend in energy band gap values of the titled glasses indicates the increasing degree of depolymerization in the network with increase in Bi2O3 content. The sample doped with 3 mol % of Bi2O3 exhibits higher luminescence at all excited wavelengths rather than other samples. Significant energy transfer parameters viz., the luminescence quantum efficiency (ηQ), energy transfer efficiency (ηET), energy transfer parameter (Q), energy transfer probability (PDA) and critical transfer parameter (R0) were evaluated for all the titled glasses by using the lifetime values. The evaluated color coordinates values at different excitation wavelengths have revealed that in general these glasses emit bright white light. But in particular the glass sample doped with 3 mol % of Bi2O3 is more suitable for the fabrication of white light emitting diodes (W-LEDs). The correlated color temperature (CCT) values for the prepared glasses are observed in the range 3300 – 4050K which are nearer to commercial and day W-LED sources. From all these investigations it can be seen that the glass doped with 3 mol % Bi2O3 is a potential candidate for the development of W-LEDs.