Shape controllable synthesis and enhanced upconversion photoluminescence of β-NaGdF4:Yb3+, Er3+ nanocrystals by introducing Mg2+

Shape controllable synthesis and enhanced upconversion photoluminescence of β-NaGdF₄:Yb³⁺, Er³⁺ nanocrystals by introducing Mg²⁺

Yang Yong-Xin^{1, 2}, Xu Zheng^{1, 2, †}, Zhao Su-Ling^{1, 2}, Liang Zhi-Qin^{1, 2}, Zhu Wei^{1, 2}, Zhang Jun-Jie^{1, 2}

(a): Schematic illustration of the proposed mechanism for the morphology conversion induced by Mg²⁺ doping in β-NaGdF₄: 20-mol% Yb³⁺, 2-mol% Er³⁺NCs. (b)–(e): TEM images of (b) NaGdF₄: 20-mol% Yb³⁺, 2-mol% Er³⁺ NCs and (c) 60-mol% Mg²⁺ doped NaGdF₄:20-mol% Yb³⁺, 2 mol% Er³⁺ NCs prepared with F to ratio of 4.0:1; (d) 60-mol% Mg²⁺-doped NaGdF₄:20-mol% Yb³⁺, 2-mol% Er³⁺ NCs with F⁻ to ratio of 3.2:1; (e) NaGdF₄:20-mol% Yb³⁺, 2-mol% Er³⁺ NCs prepared with F⁻ to ratio of 4.8:1 respectively.