Alexandrov, A.A., Mayakova, M.N., Kuznetsov, S.V. et al. Effect of Structural Perfection of Crystalline β-NaYF4:Yb,Er Phosphor Powders on the Efficiency of Their Upconversion Luminescence. Inorganic Materials. 58, 90–96 (2022). DOI:10.1134/S0020168522010010