Eu3+-based efficient red phosphors Y1-xEuxGa3(BO3)4 (0 < x ≤ 1): A potential candidate for near ultraviolet LEDs with high thermal stability

Abstract The current white light emitting diode (WLED) employs an InGaN chip together with the yellow phosphor Y 3 Al 5 O 12 :Ce 3+ , however it has a weakness of insufficient red component. In addition to traditional Eu 2+ or Mn 4+ based red phosphors, we propose that Eu 3+ in a noncentrosymmetric coordination could be an alternative for pure red emission and most importantly, it could be efficiently excited by f - f transitions in the near ultraviolet (NUV) region. Complete solid solutions of Y 1-x Eu x Ga 3 (BO 3 ) 4 were prepared by typical solid state reactions, and the crystallographic refinements proved the successful cationic substitutions, where Eu 3+ locates at the Y 3+ site exclusively. Eu 3+ is coordinated by oxygen atoms in a triangular prism symmetry, thus emits a strong and pure red light with the CIE coordinate (0.667, 0.333) upon 393 nm excitation. The internal quantum yields for the samples with x  = 0.1, 0.5 and 1 are as high as 81%, 80% and 75%, respectively. In-situ high temperature photoluminescence study confirmed that Y 0.1 Eu 0.9 Ga 3 (BO 3 ) 4 retained 84% of the emission intensity at 423 K compared to the value at room temperature, which is sufficiently good for NUV LED applications.