Features of up-conversion luminescence in concentration series of SrF2–ErF3 single crystals and nanoparticles under excitation at the 4I11/2 level of Er3+ ions

The comparative analysis of the spectral-luminescent characteristics of upconversion luminescence in the visible spectral range for concentration series of single crystals and nanoparticles (1 - x )mol.%SrF 2 – x mol.%ErF 3 ( x = 1.6%, 3.2%, 5.3%, 7.4%, 11.5%, 13.6%, 15.7%) under excitation with radiation at a wavelength of 0.972 μm to the 4 I 11/2 level of Er 3+ ions has been conducted. Interaction mechanisms in SrF 2 –ErF 3 single crystals and nanoparticles were proposed based on the analysis of changes in the ratio of lines in the luminescence excitation spectra from the 4 F 9/2 level under excitation to the 4 F 7/2 level of Er 3+ ions. The model for the occurrence of upconversion luminescence in the visible spectral range in SrF 2 –ErF 3 single crystals and nanoparticles under excitation with radiation at a wavelength of 0.972 μm to the 4 I 11/2 level of Er 3+ ions has been proposed.