Figure 1

TEM images of the as-synthesized (a) NaYF4, (b) 30%Mn 5%Yb 120 °C, (c) 30%Mn 5%Yb 140 °C, (d) 30%Mn 5%Yb 160 °C, (e) 30%Mn 5%Yb 180 °C, and (f) 30%Mn 5%Yb 200 °C. The analyzed samples were in solution form.

TEM images of the as-synthesized (a) NaYF4, (b) 30%Mn 5%Yb 120 °C, (c) 30%Mn 5%Yb 140 °C, (d) 30%Mn 5%Yb 160 °C, (e) 30%Mn 5%Yb 180 °C, and (f) 30%Mn 5%Yb 200 °C. The analyzed samples were in solution form.