Synthesis and Characterization of Highly Efficient Near-Infrared Upconversion Sc³⁺/Er³⁺/Yb³⁺Tridoped NaYF₄

The blue, green, red, and UV upconversion (UC) emissions of hexagonal NaYF 4 were obviously enhanced by tridoping the structure with Sc 3+ /Er 3+ /Yb 3+ . The effect of Sc 3+ tridoping on the upconversion luminescence of NaYF 4: Er 3+ /Yb 3+ was investigated in detail. The blue, green, and red upconverted emissions corresponding to the excitation of infrared 980-nm light were remarkably enhanced and the decay time was obviously prolonged with different quantity Sc 3+ tridoping. X-ray diffraction, X-ray photoelectron spectroscopy, and decay time investigations evidence that Sc 3+ ions can tailor the local crystal field of the NaYF 4 host lattice, and the energy level 4 S 3/2 was split. The UC emissive intensity mechanism was discussed based on XRD, XPS, and PL analysis data. This material is expected to be widely applied in biomedical, UC laser, solar energy, etc.