Reduction of Eu3+ to Eu2+ in Ba1−xSrxGd1−yYyB9O16:Eu phosphor: Synthesis, composition controlling, and tunable luminescence

Abstract

Eu2+ and Eu3+ codoping phosphor have attracted much attention due to their tunable luminescence color and potential application in lighting and display. In this work, Eu3+ ions are controllably reduced to Eu2+ ions in Ba1-xSrxGd1-yYyB9O16 to synthesize Eu2+ and Eu3+ codoping phosphors by using a high-temperature solid-state method. In the obtained phosphors, the Eu2+ shows a blue emission of ∼460 nm, and Eu3+ shows a characteristic red emission with a maximum at ∼617 nm. The relative emission intensity of Eu2+ and Eu3+ can be tuned by the incorporation of Sr2+ or Y3+, which results in a tunable luminescence color in the range of purplish blue to purplish red. The results indicate that BaGd0.2Y0.76B9O16:0.04Eu simultaneously show bright red and blue emission, and its chromatic coordinate is the closest to the white-light region. The tunable luminescence color is explained on the basis of the crystal structure of BaGdB9O16.