Luminescence and energy transfer in warm white-light-emitting K3Y(PO4)2:Tb,Eu phosphor for LEDs applications

To obtain warm white-emission in a new single-phase phosphor, a series of Tb–Eu doped K3Y(PO4)2 (KYP) samples were prepared by solid-state reaction method, and their photoluminescence properties were investigated. For Tb-single-doped KYP, the green emission mainly owing to the 5D4–7FJ (J = 3–6) transitions was obtained. For Eu-single-doped KYP, two kinds of emissions were observed, i.e., the line-peak and broad-band emissions, belonging to the Eu3+ 5D0–7FJ (J = 0–4) and Eu2+ d–f transitions, respectively. When Tb–Eu ions were co-doped into the KYP host, the Eu2+, Tb3+ and Eu3+ emissions were all found, which contribute to the blue, green and red components in the visible spectrum, respectively. By adjusting the relative concentrations of Tb and Eu, the emitting light color can be tuned and the warm white-emission was gained in the KYP:0.03 Tb,0.03Eu phosphor. The thermal luminescence stability of the KYP:0.03 Tb,0.03Eu sample was studied. The above investigations reveal that the present phosphors could have potential application in white LEDs.