Infrared-to-visible upconversion luminescence in SrF₂:Er powders upon excitation of the ⁴I_13/2 level

Abstract

Fluorite-type SrF2:Er powders were synthesized by using a co-precipitation from the aqueous solution technique. X-ray powder diffraction, scanning electron microscopy, absorption and luminescence spectroscopy were used to characterize the samples. For the first time upconversion luminescence of SrF2:Er powders in the visible and near-infrared spectral region upon excitation of 4I13/2 level Er3+ ions was investigated. The decrease in the slopes of the visible upconversion luminescence with increasing excitation power density and concentration of Er3+ ions were experimentally observed and discussed. The most intensive visible luminescence was obtained for SrF2:Er (8.8%) with a maximum quantum yield of 0.19%. Chromaticity coordinates and color temperature of yellow-green upconversion luminescence of SrF2:Er were calculated.