Study of photoluminescence properties of Er3+ ions in SiO2–GeO2 and Al2O3 nanoparticles

We have used the sol–emulsion–gel method to prepare nanoparticles of SiO2, SiO2–GeO2 and Al2O3 doped by the same concentration Er3+ ions for comparison. We have compared the luminescent efficiencies of these particles and we found that the luminescence spectra and lifetime of the excited state 4I13/2 of Er3+ ions are found to be sensitive to the nature of host. A broad emission spectrum of width 58–55 nm peaked at wavelength of 1.5 μm and the decay times of 4I13/2→4I15/2 transition are 7.57 and 2.07 ms for 1000 °C heat-treated 1.0 mol% Er3+ doped SiO2–GeO2 and Al2O3 nanoparticles, respectively. The analysis suggests that modification of relaxation mechanism is due to the nature of the host.