Achieving high-efficiency green NaYSiO4:Tb phosphors by optimizing host structure through cation doping

Abstract

Rare earth activated color converted phosphors have been widely used in solid-state lighting and display fields. Developing phosphors with high luminous efficiency is of great significance for light-emitting devices. Concentration quenching is the main factor limiting the improvement of phosphor luminescence efficiency during increasing the activator doping level. In this study, a novel structural optimization strategy is developed to overcome the impact of concentration quenching. In Tb3+ activated NaYSiO4 (NYSO), large-size Gd3+ ions are introduced to adjust the distance of rare earth ions and suppress the energy transfer between Tb3+ luminescent centers. It is shown that at a critical Tb3+ concentration, for which concentration quenching tends to occur in NaYSiO4:Tb3+, Gd3+ incorporation successfully raises the internal quantum efficiency from 64.8 % for Tb3+-singly-doped NYSO up to 80.6 % for Gd3+/Tb3+ co-doped one. The findings can offer a feasible pathway in promoting the luminescent properties of silicate phosphor hosts.