Up-conversion luminescence and near-infrared quantum cutting of Ho3+/Yb3+ co-doped hexagonal NaGdF4 phosphors.

In this paper, Ho³⁺/Yb³⁺ co-doped Sodium Gadolinium Fluoride (NaGdF₄) phosphors were synthesized by a facile and efficient hydrothermal method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy spectrum (EDS), and photoluminescence (PL). The results of XRD and SEM indicated that the prepared NaGdF₄ samples have the hexagonal structure and good orientation in the case of changing the concentration of Yb³⁺. The results of pump power dependence of up-conversion intensity indicated that the energy transfer mechanism from Yb³⁺ to Ho³⁺ is a two-photon process. The energy transfer between Ho³⁺ and Yb³⁺ under 448 nm excitation was determined by PL spectra and fluorescence lifetimes. All the results proved that the doping of Yb³⁺ ions can effectively improve the up-conversion luminescence of NaGdF₄ phosphors and achieve quantum cutting efficiency of up to 179.8%. Overall, NaGdF₄:Ho³⁺/Yb³⁺ have potential application in the field of optoelectronic materials. [ABSTRACT FROM AUTHOR]