LAUSR

Abstract The purpose of this work is to develop a single-phase phosphor emitting white light under the excitation of near UV light, targeted at the possible application in white light emitting diodes. Our rationale is to employ a host containing noncentrosymmetric coordination sites for rare earth, therefore the f-f absorptions in the near UV range could be enhanced. Indeed, YGa3(BO3)4 is such a host where Y3+ is in a twisted triangular prism and could be substituted by various rare earth elements. The photoluminescence of Dy3+ and Tm3+ were investigated in Y1-xDyxGa3(BO3)4 (0 ≤ x ≤ 0.10) and Y1-yTmyGa3(BO3)4 (0.01 ≤ y ≤ 0.10), whose phase purity was confirmed by powder X-ray diffraction. Dy3+ emits yellowish white light and Tm3+ emits blue light under their respective f-f excitations (350 and 358 nm). The optimal concentrations in the singly-doped phosphors are 7 and 3 atom%, respectively. When co-doping Dy3+ and Tm3+ in YGa3(BO3)4, there was no energy transfer between them. Eventually, a white light emission could be obtained with the CIE coordinates of (0.325, 0.329) in Y0.91Dy0.07Tm0.02Ga3(BO3)4 under the excitation of 364 nm.