Well-Organized Single White-Emitting GdMoBO6:Eu3+, Tb3+, Dy3+/Bi3+ Phosphors Enabled by the Energy Transfer Process for White LED-Based Indoor Lighting

Abstract

In recent years, single white-emitting phosphors and their optical properties have attracted extensive worldwide attention. Aiming at this fact, a series of near-UV excitable Tb3+, Eu3+, and Bi3+/ Dy3+-codoped GdMoBO6 phosphors were developed. Under UV excitations, individual Eu3+ and Tb3+-activated GdMoBO6 phosphors exhibit exceptional red and green emissions due to Tb3+ (5D4 → 7FJ=3–6) and Eu3+ (5D0 → 7FJ=1–4) transitions. The tunable color tone (green to yellowish white) has been obtained in Eu3+ and Tb3+-codoped GdMoBO6 phosphors due to the sensitizing effects of the self-activated host, and the energy transfer process from Tb3+ ions to Eu3+ ions. Additionally, Dy3+/Bi3+ ions were included in the optimized Eu3+-Tb3+-codoped system to enhance the photoluminescence further via the sensitizing effect of the Dy3+/Bi3+ ions. When combined with a 370 nm UV LED chip, the Gd0.573MoBO6:0.04Tb3+, 0.007Eu3+, 0.02Dy3+ system exhibited white light emission with a color rendering index (Ra) of ∼87 and a correlated color temperature of ∼4960 K. Whereas, Gd0.573MoBO6:0.04Tb3+, 0.007Eu3+, 0.02Bi3+ showed a white light emission with a color rendering index (Ra) of 81 and a correlated color temperature of 5114 K. These optimized single-component white-emitting phosphors have potential for white LED-based lighting applications.