Herein, we report near-infrared-to-visible up-conversion (UC) in SrF2:Yb3+,Er3+ sub-micron crystals prepared via a facile route in an aqueous solution. Subsequent calcination at 600 °C allows us to achieve good UC quantum yields, reaching 2.8 % at an excitation power density of 10 W/cm2 for a sample doped with 2 mol.% of Yb3+ and 2 mol.% of Er3+.
This UC quantum yield of SrF2:Yb3+,Er3+ is in the range of record UC quantum yields reported in the literature for standard host systems such as La2O2S, BaY2ZnO5 and NaYF4 phosphors. Interestingly, the 2 mol.% of Yb3+ required to achieve optimal UC in the SrF2 host is much lower than the amount of Yb3+ required in the other host systems.
Furthermore, we studied the population and depopulation kinetics of Er3+:2H9/2 Er3+:2H11/2,4S3/2 and Er3+:4F9/2 states using time-resolved photoluminescence measurements in order to provide insight into the UC mechanism. The facile preparation method combined with high UC quantum yield make SrF2:Yb3+,Er3+ materials attractive candidates for solar energy harvesting, sensors, solid state lasers, and luminescent markers.
Kuznetsov, S., Ermakova, Y., Voronov, V., Fedorov, P.P., Busko, D., Howard, I.A., Richards, B.S. and Turshatov, A., 2017. Up-conversion Quantum Yield of SrF 2: Yb 3+, Er 3+ Sub-micron Particles Prepared by Precipitation from Aqueous Solution. Journal of Materials Chemistry C.
Redirect to full article: Click Here