Effect of optical basicity on Er3+ up-conversion luminescence in GeO2–R2O glasses

The effect of optical basicity on Er3+ up-conversion luminescence in germanate glasses is investigated under 980 nm excitation. The intensity of green and red up-conversion luminescence decreased with the increase in radius of alkali ion or Li2O content, implying that up-conversion luminescence strongly relates to the optical basicity of glass host. On the other hand, as increasing the optical basicity, the red emission intensity decreased significantly, while the green emission intensity decreased slightly. It has been proposed that the up-conversion luminescence intensity was dominated by the optical basicity, which theoretically estimated from glass composition. The interaction mechanism between up-conversion process and optical basicity was proposed.