Stable Tunable Luminescence of Hetero-valent Eu Ion Activated BaInTaO Phosphors Synthesized by Defect-Induced Self-Reduction in the Molten-Salt Method.

Functional materials with stable and adjustable luminescence have recently become a research hotspot for their broad application prospects. Tunable luminescence can be realized by the doping of hetero-valent europium ions. High-temperature hydrogen atmosphere reduction is required in the traditional preparation of Eu-doped phosphors. Herein, an anoxic molten-salt medium environment was established to form oxygen vacancy defects in the reaction system and induce the self-reduction of Eu ions to obtain Eu ions. X-ray photoelectron spectroscopy (XPS) results confirm the existence of Eu and Eu ions in the samples, and the fluorescence spectrum shows that hetero-valent Eu ions can synergistically emit light effectively. Under 266 nm ultraviolet light excitation, the white light emission was successfully realized for a BaInTaO:Eu phosphor by different emission combinations of Eu and Eu ions. In addition, the BaInTaO:Eu phosphor exhibits adjustable luminescence from greenish-yellow to red exciting at 390-490 nm, which has superior stability in a high-temperature and high-humidity environment. Therefore, it is very promising that BaInTaO:Eu will be used as multi-color functional materials in many fields such as communication encryption and colorful decoration.