Yellow phosphors of high quantum yields excitable by both ultraviolet and blue light with Gd₃BWO₉ as the host

Yellow phosphors play an important role in the fabrication of white light LEDs. In this study, we synthesized a series of yellow phosphors with Gd₃BWO₉ (GBWO) as the host material. The broad emission band in the range of 400 ​nm–620 ​nm is attributed to the ³P₀→¹S₀ transition of Bi³⁺. The emission color is tuned from green to yellow by co-doping of Eu³⁺ or Sm³⁺ with Bi³⁺ in GBWO. Additionally, yellow phosphors excited by blue light (λ_ex ​= ​487 ​nm) were obtained by co-doping Tb³⁺ with Eu³⁺ or Sm³⁺ in GBWO host. The emission can be tuned from green to yellow and orange by adjusting the ratio of Tb³⁺/Eu³⁺ and Tb³⁺/Sm³⁺. The quantum yield of GBWO:0.25 ​Tb³⁺, 0.03Eu³⁺ yellow phosphor reaches 70.2%, and the quantum yield of GBWO:0.25 ​Tb³⁺, 0.05Eu³⁺ orange phosphor is as high as 83.7%. The present yellow phosphors that can be excited by both ultraviolet and blue light and having high quantum yields can be candidates for the application in white LED.