Effect of charge compensators (Li+, Na+ , K+) on the luminescence properties of Sr3TeO6:Eu3+ red phosphor

A double-perovskite Sr3TeO6:Eu3+ red phosphor was successfully prepared and confirmed to be a single phase through X-ray diffraction. Under an optimal excitation wavelength (394 nm), the Sr3TeO6:Eu3+ phosphor emitted intense red light at 617 nm, which corresponded to D-5(0)-> F-7(2) transition. When the concentration of Eu3+ exceeded the optimal doping concentration (25 mol%), concentration quenching occurred because of the interactions among the nearest neighbor ions. The phosphor exhibited excellent thermal stability, and the E-a value was 0.27 eV. In accordance with Judd-Ofelt theory, the low symmetry of Eu3+ ions was confirmed, and it resulted in a color purity of up to 99.5%-99.8%. Among the charge compensators (Li+, Na+, and K+), the Na+ ions had the best charge compensation effect. The luminescence intensity of Sr3TeO6:Eu3+, Na+ was approximately 2.06 times that of Sr3TeO6:Eu3+ and 2.25 times that of commercial phosphor (Y2O3:Eu3+). The fabricated red LED has the potential to be used for plant and herb cultivation. A white light-emitting diode (w-LED) was successfully prepared, and related parameters were established. The R-a value of the prepared w-LED was as high as 91, and R-9 was 5.7 times that of a commercial w-LED. These characteristics indicate that phosphors have potential in the solid-state lighting field.