Tailoring multiphonon relaxation and cross relaxation energy transfer in mixed ionic-electronic 20Li2O-xBi2O3-(78-x)TeO2-1Er2O3-1Ag glasses at NIR region

Abstract

A glass composed of 20Li2O-xBi2O3-(78-x)TeO2-1Er2O3-1Ag was fabricated by melt–quenching method to examine the influence of mixed ionic–electronic (MIE) effect on AC conductivity (σAC) and photoluminescence properties. The σAC decreased as the Bi2O3 content increased, until a minimum σAC at x=11 mol% attributable to the MIE effect was achieved. The photoluminescence intensity and lifetime (τmes)of the 4I13/2→4I15/2 transition were reported with a drop at x=11 mol%, coincided with the minimum σAC. Results on the analysis of the multiphonon relaxation rate (WMPR) revealed that adding low-phonon Bi2O3 concentration promoted higher photoluminescence intensity and longer τmesdue to the reduction in WMPR. However, the drop in photoluminescence intensity and τmes at x=11 mol% may be due to a blocking effect. The blocking effect may have induced nonradiative phonon-assisted Sab and cross-relaxation γ6 energy transfer, leading to a maximum WMPR and energy transfer parameter.