Optical spectroscopy and Judd-Ofelt analysis of Eu3+ doped in Na2ZnP2O7 with high thermal stability for display applications

Na2ZnP2O7: x mol. % Eu3+ phosphors with different dopant concentrations (x = 1, 2, 4, 6, 8) have been synthesized via high-temperature solid-state reaction. X-ray diffraction, scanning electron microscopy analyses and infrared (IR) spectroscopy were applied for detailed structural characterization. Under 393 nm excitation, the photoluminescence spectra displayed the D-5(0) -> F-7(J) (J = 1, 2, 3, 4) intra-4f shell transitions related to Eu3+ ion. The radiative lifetime was estimated using the Omega(2) and Omega(4) Judd-Ofelt (J-O) intensity parameters. The highest luminescence intensity was achieved for an optimal europium concentration of 4 mol. %. The temperature-dependent photoluminescence and Commission Internationale de l'Eclairage chromaticity diagram were investigated. It was found that Eu3+-doped Na2ZnP2O7 exhibited good thermal stability and its emission intensity decreased slightly above room temperature. In addition, the color purity of this phosphor was about 99%. Na2ZnP2O7: Eu3+ phosphor can be considered as potential red phosphor for application in ultraviolet-pumped white light-emitting diodes.