Up-conversion Quantum Yield of SrF2:Yb3+,Er3+ Sub-micron Particles Prepared by Precipitation from Aqueous Solution. Journal of Materials Chemistry C. 2018,6, 598-604 

S. Kuznetsov, Yu. Ermakova, V. Voronov, P. Fedorov, D. Busko, I.A. Howard, B.S. Richards and A. Turshatov. Up-conversion Quantum Yield of SrF2:Yb3+,Er3+ Sub-micron Particles Prepared by Precipitation from Aqueous Solution. Journal of Materials Chemistry C. 2018,6, 598-604