Synthesis and properties of novel Pb/La/WO4: Eu3+ red phosphors for white light emitting diodes (WLEDs)

A novel red emitting phosphor PbLa2–2xEu2xW4O16(0 ≤ x ≤ 1) was successfully synthesized via solid-state method. Structure and crystallite size were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). Excitation transmission and photoluminescence (PL) properties of the samples have been studied. The prepared red phosphor of PbLa1.13Eu0.88W4O16 demonstrated the highest red luminescence compatible with electronic transition 5D0→7F2 at 615 nm during the excitation by Light-emitting diode (LED) with a wavelength of 460 nm which corresponds to the excitation band 7F0→5D2. Moreover, the intensity parameters Ω2,4 and the quantum efficiency of the PbLa1.13Eu0.88W4O16 were calculated based on the Judd-Ofelt's theory. We compared the PL properties of our prepared red phosphors with the compound of BaGd1.3Eu0.7(MoO4)4. Such comparison is a clear evidence of the superior efficiency of our prepared red phosphors for several applications related to the White Light Emitting Diodes (WLEDs).