Blue-emitting Ba2Ca(PO4)2:Eu2+, Tb3+ phosphor for full-spectrum w-LEDs applications

Abstract

Ba2Ca(PO4)2:xEu2+, yTb3+ phosphors with good crystallinity and morphology was prepared by high-temperature solid-state method. The optimal excitation wavelength of Ba2Ca(PO4)2:xEu2+, yTb3+ phosphor is 349 nm, it shows a broad emission band with the highest peak at 453 nm and a narrow emission band at 544 nm after being excited. With the addition of Tb3+, the blue emission peak intensity of Eu2+ increase, the intensity of blue emission(453 nm) in Ba2Ca(PO4)2:0.5%Eu2+, 1%Tb3+ (y = 1%) is more than three folds that of Ba2Ca(PO4)2:0.5%Eu2+(y = 0). The energy transfer from Tb3+ to Eu2+ and the promotion of Eu3+→Eu2+ reaction by co-doping Tb3+ in BCP enhances the blue emission intensity. In Ba2Ca(PO4)2 matrix, the energy transfer mechanism from Tb3+ to Eu2+ is electric dipole-dipole interaction, and the energy transfer efficiency can reach up to 88%. The activation energy of Ba2Ca(PO4)2:0.5%Eu2+, 1%Tb3+ phosphor is 0.229 eV, which indicates that it has good thermal stability. The w-LED made of ultraviolet chip and Ba2Ca(PO4)2:0.5%Eu2+, 1%Tb3+ and Ba2Mg(PO4)2:1%Eu2+ phosphors has ultrahigh color rendering index (Ra = 92.0). Ba2Ca(PO4)2:xEu2+, yTb3+ powder is a new blue-cyan phosphor that can be applied to full-spectrum w-LEDs.