Yb³⁺/Er³⁺ co-doped NaYF₄ (NaYF₄: Yb³⁺, Er³⁺) hexagonal nanoplates were synthesized by a tetrasodium iminodisuccinate assisted hydrothermal synthesis method for the first time. The crystal structure and morphology was investigated by the X-ray diffraction and scanning electron microscope analysis. The upconversion luminescent property of the synthesized NaYF₄: Yb³⁺, Er³⁺ hexagonal nanoplates was discussed as a function of Yb³⁺ and Er³⁺ concentration. Under 980 nm excitation, NaYF₄: Yb³⁺, Er³⁺ hexagonal nanoplates exhibited strong red emissions near 660 nm and green upconversion emissions at 530 and 550 nm corresponding to the intra 4f transitions of Er³⁺ (⁴F_9/2, ²H_11/2, ⁴S_3/2) → Er³⁺ (⁴I_15/2). The Yb³⁺ 5 mol% and Er³⁺ 0.5 mol% co-doped NaYF₄ sample exhibited strongly shiny upconversion emission, which was considered to be the optimum doping concentration. A possible upconversion mechanism for NaYF₄: Yb³⁺, Er³⁺ depending was discussed in detail.

Keywords: hydrothermal, NaYF₄, upconversion, IDS