A potential red-emitting phosphor Ca2YTaO6:Eu3+: Luminescence properties, thermal stability and applications for white LEDs

A novel red-emitting phosphor tantalate Ca2YTaO6:Eu3+ was synthesized by a solid-state reaction. The purity and surface morphology of the phosphors were characterized. The Ca2YTaO6:Eu3+ phosphors show a sharp emission peak at 612 nm under near-ultraviolet (n-UV) at 395 nm because of the 5D0 → 7F2 transition of Eu3+. The optimal Eu3+ doping concentration in Ca2YTaO6 is 40 mol% and the critical energy-transfer distance of Eu3+ ions was calculated to be 0.9 nm. The emission spectra of Ca2YTaO6:Eu3+ from 300 to 480 K were investigated. The thermal-quenching temperature (T0.5) of Ca2YTaO6:Eu3+ is above 480 K. The color purity of Ca2YTaO6:40 mol%Eu3+ is as high as 99.8%. The luminescence lifetime of Ca2YTaO6:40 mol%Eu3+ was also discussed. The high color purity and high thermal stability of Eu3+-doped Ca2YTaO6 phosphors contribute to its application value in white light-emitting diodes (w-LEDs).