Luminescence properties and energy transfer of Tb 3+ , Eu 3+ co-doped YTaO 4 phosphors obtained via sol-gel combustion process.

Tantalate is considered as a valuable and efficient luminescence host because of its intense absorption in the ultraviolet area and excellent chemical properties. In this work, a series of pure YTaO 4 :Eu 3+ and/or Tb 3+ crystals were prepared via a sol-gel combustion method. The morphology, structure, and optical properties of the samples were discussed in detail. The Eu 3+ , Tb 3+ co-doped YTaO 4 samples are consisted of small spherical particles of around 18 nm. The prepared YTaO 4 :Tb 3+ and/or Eu 3+ samples exhibit the characteristic wide excitation band around 210-300 nm, the characteristic narrow red emission of Eu 3+ ( 5 D 0  →  7 F 2 ) transitions and green emission of the Tb 3+ ( 5 D 4  →  7 F 5 ) transitions when excited by UV light. It is focused on the energy transfer processes from the YTaO 4 to Tb 3+ as well as Eu 3+ ions and from Tb 3+ to Eu 3+ ions of YTaO 4 :Eu 3+ /Tb 3+ phosphors. Color-tunable emissions are realized through adjusting the types of rare earth ion (Eu 3+ and Tb 3+ ) and relative doping concentrations excited by a single wavelength. That is to say, the obtained Tb 3+ and Eu 3+ co-doped YTaO 4 phosphors have a promising prospect in lasers, white light diodes (WLED), fluorescent lamp, and field emission display devices, etc.