Enrichment of orange emission of Er3+ ion with Sn4+ ion as sensitizer in lithium lead phosphate glass system

Lithium lead phosphate glasses doped with 1.0 mol% of Er2O3 and mixed with varying concentrations of SnO2 (from 0 to 7.0 mol%) have been synthesized. Optical absorption and luminescence spectra of the prepared glasses were recorded at ambient temperature. The radiative lifetimes were measured from the luminescence decay profiles recorded at room temperature. Similar studies have also been carried out for the SnO2 singly doped glasses. The absorption and luminescence spectra of Er3+ ions doped glasses were characterized using Judd-Ofelt theory. The radiative parameters viz., transition probability A, branching ratio beta and the radiative lifetime 2 of principal emission transitions of these glasses have been evaluated. The energy transfer mechanism between Sn4+ and Er3+ in co-doped glasses has been explored as a function of SnO2 concentration with the help of rate equations. The results indicated a significant enhancement in the intensity of orange emission 4(G11/2) -> 4I(11/2) of Er3+ ions due to co-doping with SnO2. The results were further analyzed with IR spectral data and ac conductivity studies. The analysis pointed out that about 3.0 mol% of SnO2 is the most favorable concentration for getting the highest quantum efficiency of orange emission and for the maximum energy transfer with low non-radiative transition probabilities. (C) 2015 Elsevier B.V. All rights reserved.