Novel synthesis of up-conversion phosphor based on rare-earth doped NaLaF₄

In this work Er³⁺ doped NaLaF₄ material has been synthesized Along with the description of the synthesis route, luminescence spectra and decay kinetics of both traditional and up-conversion luminescence of Er³⁺ will be presented for different Er³⁺ doping levels. It will be shown that the main mechanisms involved in the creation of the up-conversion luminescence in NaLaF₄:Er³⁺ under excitation at about 975 nm are excited state absorption and energy transfer. Relative impact of either of the mechanisms in NaLaF₄:Er³⁺ depends on both the concentration of Er³⁺ and on the excitation wavelength: the increase of either the concentration or the excitation wavelength leads to the prevalence of energy transfer mechanism over excited state absorption mechanism.