Experimental optimum design and luminescence properties of NaY(Gd)(MoO₄)₂: Er³⁺ phosphors

Three-factor orthogonal design (OD) of Er³⁺/Gd³⁺/T (calcination temperature) is used to optimize the luminescent intensity of NaY(Gd)(MoO₄)₂:Er³⁺ phosphor. Firstly, the uniform design (UD) is introduced to explore the doping concentration range of Er³⁺/Gd³⁺. Then OD and range analysis are performed based on the results of UD to obtain the primary and secondary sequence and the best combination of Er³⁺, Gd³⁺, and T within the experimental range. The optimum sample is prepared by the high temperature solid state method. Photoluminescence excitation and emission spectra of the optimum sample are detected. The intense green emissions (530 nm and 550 nm) are observed which originate from Er^{3+ 2}H_11/2→⁴I_15/2 and ⁴S_3/2→⁴I_15/2, respectively. Thermal effect is investigated in the optimum NaY(Gd³⁺)(MoO₄)₂:Er³⁺ phosphors, and the green emission intensity decreases as temperature increases.