Na2Tb0.5(MoO4)(PO4):0.5Eu3+: A red-emitting phosphor with both high thermal stability and high colour purity

Abstract

A novel red-emitting Na2Tb0.5(MoO4)(PO4):0.5Eu3+ phosphor was successfully synthesized via high temperature solid-state reaction method to explore new red emissions with high thermal stability and high colour purity. The results indicate that the alternating tetrahedrons of [PO4]3- and [MoO4]2- formed in the three-dimensional structure play a decisive role in isolating Tb3+ and Eu3+ ions. This structural isolation increases the concentration quenching of Tb3+ and Eu3+ in single-doped phosphors by more than 50%. In co-doped phosphors, the energy transfer from Tb3+ to Eu3+ was verified by the overlap of luminescent spectra and variations in decay curves. The emission colour of Na2Y1-x-y(MoO4)(PO4):yTb3+,xEu3+ can be tuned from green to red through the energy transfer process by adjusting the ratio of Tb3+/Eu3+. The emission intensity at 150 °C is 84.7% compared to room temperature, as well as the remarkable correlated colour temperature (2425 K) and high colour purity (95.3%) with CIE chromaticity coordinates (0.654, 0.345) make Na2Tb0.5(MoO4)(PO4):0.5Eu3+ as an incredible red-emitting phosphor for both display devices and warm white lighting applications.