In-doped LiCa_2.98MgV₃O₁₂ rare-earth-free phosphor with a high photoluminescence quantum yield of 67.4%

Rare earth resources applied in numerous novel materials, are increasingly scarce in worldwide. Meanwhile, great attention has been focused on the blue rare-earth-free fluorescent phosphors as an excitation source of near-ultraviolet (NUV) chips, which are available in white-light-emitting diodes (WLEDs) that combined with yellow commercial phosphors. Many solutions have been found to improve the photoluminescence quantum yield (PLQY) of phosphor. In this study, we effectively increased PLQY by introducing indium ion to vanadate garnet phosphor forming a series of LiCa_3−XMgV₃O₁₂: xIn³⁺ (x = 0.01, 0.02, 0.04, 0.06, 0.08, and 0.10). The resultant In-doped vanadate garnet phosphors exhibit a relative increase in PLQY, and the optimal phosphors is LiCa_2.98MgV₃O₁₂: 0.02In³⁺ with a PLQY as high as 67.4%. These In-doped vanadate garnet phosphors have a broad emission at 480 under 320 nm where near UV-light excitation. It is revealed that the distortion of V-V and V-O bond length in [VO₄] crystal structure and unit cell volume data of phosphors have an extensive influence on PLQY. Therefore, these novel vanadate garnet phosphors can be the essential blue color choice for WLED devices application in illumination.