Luminescence properties and energy transfer of Tb~(3+), Eu~(3+) co-doped YTaO_4 phosphors obtained via sol-gel combustion process

摘要

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+) (~5D_0→~7F_2) transitions and green emission of the Tb~(3+) (~5D_4→~7F_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.