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}

The TEM images of β-NaGdF₄:20-mol% Yb³⁺, 2-mol% Er³⁺ NCs codoped with (a) 0-mol%, (b) 40-mol%, (c) 50-mol%, (d) 60-mol%, and (e) 70-mol% Mg²⁺ ions; (f) HR-TEM image of a single nanoplate of 60-mol% Mg²⁺ codoped NaGdF₄:20-mol% Yb³⁺, 2-mol% Er³⁺ NCs. Inset: fast Fourier transform (FFT) of the HR-TEM image exhibits a hexagonal symmetry.