Luminescent Properties and Charge Compensator Effects of SrMo(0.5)W(0.5)O(4):Eu(3+) for White Light LEDs

The high-temperature solid-phase approach was used to synthesize Eu(3+)-doped SrMo(0.5)W(0.5)O(4) phosphors, whose morphological structure and luminescence properties were then characterized by XRD, SEM, FT-IR, excitation spectra, emission spectra, and fluorescence decay curves. The results reveal that the best phosphor synthesis temperature was 900 °C and that the doping of Eu(3+) and charge compensators (K(+), Li(+), Na(+), NH(4)(+)) had no effect on the crystal phase change. SrMo(0.5)W(0.5)O(4):Eu(3+) has major excitation peaks at 273 nm, 397 nm, and 464 nm, and a main emission peak at 615 nm, making it a potential red fluorescent material to be used as a down converter in UV LEDs (273 nm and 397 nm) and blue light LEDs (464 nm) to achieve Red emission. The emission spectra of Sr(1−y)Mo(0.5)W(0.5)O(4):yEu(3+)(y = 0.005, 0.01, 0.02, 0.05, 0.07) excited at 273 were depicted, with the Eu(3+) concentration increasing the luminescence intensity first increases and then decreases, the emission peak intensity of SrMo(0.5)W(0.5)O(4):Eu(3+) achieves its maximum when the doping concentration of Eu(3+) is 1%, and the critical transfer distance is calculated as 25.57 Å. When various charge compensators such as K(+), Li(+), Na(+), and NH(4)(+) are added to SrMo(0.5)W(0.5)O(4):Eu(3+), the NH(4)(+) shows the best effect with the optimal doping concentration of 3wt%. The SrMo(0.5)W(0.5)O(4):Eu(3+),NH(4)(+) color coordinate is (0.656,0.343), which is close to that of the ideal red light (0.670,0.333).