Multicolor Emission Tuning and Red/Green Ratio Enhancement of Yb³⁺/Er³⁺ Codoped KGdF₄ Upconversion Nanoparticles

Figure 2

FE-SEM images of KGdF₄:Yb³⁺/Er³⁺ UCNPs with doping different Yb³⁺ ions: (a) 18%, (b) 38%, (c) 58%, (d) 78%, and (e) 98%; the EDS of (f) KGdF₄:18%Yb³⁺/2%Er³⁺ and (g) KGdF₄:98%Yb³⁺/2%Er³⁺ UCNPs.

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