The Effect of Eu³⁺ Concentration in α-Gd₂(MoO₄)₃:Eu³⁺ Red Phosphors for Warm WLEDs

GaN chip based solid-state lighting applications has been paid much attention towards the development of white light-emitting diodes (WLEDs). WLEDs are producing by the combination of blue LED chip and yellow emitting Y₃Al₅O¹²:Ce³⁺ phosphors because of their high luminescence efficiency, high thermal stability and low cost. However, its luminescence suffers from problems such as cold white light (high color temperature) and a low color-rendering index (CRI), which results from the lack of red spectral contribution. Although many approaches were developed to improve the CRI and color temperature, it is still necessary to develop new red phosphors with good color purity and high absorption in near-UV or blue wavelength region. Herein, Eu³⁺ doped α-Gd₂(MoO₄)³ red phosphors sintered at 800℃ were synthesized by a solid-state method. The effect of Eu³⁺ concentration in crystal structure, morphology and luminescent properties of phosphors was investigated by using X-ray diffraction (XRD), field emission scanning electron microscope (SEM) and photoluminescence excitation and emission(PL/PLE).