Cookies

We use cookies to ensure that we give you the best experience on our website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue.

Durham University

Department of Chemistry

Publication details for Prof. Ivana Evans

Rodriguez-Garcia, Melissa Monzerrat, Williams, J. A. Gareth & Evans, Ivana Radosavljevic (2019). Single-Phase White-Emitting Phosphors Based on Apatite-Type Gadolinium Silicate, Gd9.33(SiO4)6O2 Doped with Dy3+, Eu3+ and Tb3+. Journal of Materials Chemistry C 7(25): 7779-7787.

Author(s) from Durham

Abstract

Two series of new apatite-type silicate materials were synthesised and characterised with the aim of achieving white light emission from single-phase phosphors. The Gd9.33(SiO4)6O2 host was doped systematically with Dy3+, Tb3+ and Eu3+ to tune the emission to the white light region. Eight new phosphors with emission very near the ideal white light point are reported. The best properties are found for the 0.5%Tb, 0.03%Eu co-doped Gd9.33(SiO4)6O2 , with colour coordinates (0.340, 0.341) and a correlated colour temperature of 5190 K, corresponding to the white light region. The temporal decay of emission from the doped ions was measured following pulsed excitation of the Gd3+ host. An evaluation of energy transfer and quenching effects in the phosphors has been made based on the lifetimes so obtained. In particular, a comparison of the Eu3+ lifetimes in the Dy,Eu co-doped phosphors with those in the Tb,Eu-containing materials suggests quenching of the 5D0 excited state of Eu3+ by the Dy3+ ions. These observations imply that the combination of Eu3+ and Dy3+ ions may not provide optimal efficiencies in phosphors, and that the combination of Eu3+ and Tb3+ is likely to be superior for optimising the emission properties.