Tm3+/Dy3+/Eu3+ (Sm3+) tri-activated Y2WO6 as one potential single-phase phosphor for WLEDs

Pure phase Tm3+, Dy3+, Sm3+ and Eu3+ co-activated Y2WO6 single crystal phosphors are synthesized through a hydrothermal method. Upon the excitation of 311 nm, Tm3+, Dy3+, Sm3+ and Eu3+ show tremendous emission properties in their corresponding regions. The optimum concentration of Tm3+ for Y2WO6 phosphors is measured to be around 4%. The energy transfer efficiency from Tm3+ to Dy3+ in-creases gradually with increasing concentration of Dy3+, and reaches up to 72% at 10%Dy3+. The critical distance between Tm3+ and Dy3+ is calculated to be 16.77 angstrom. Hence, dipole-dipole interaction dominates the mechanism of energy transfer. The color tone of Y2WO6. Tm3+, Dy3+ phosphors was effectively tuned to warm white light by co-doping Sm3+ or Eu3+. Furthermore, the energy transfer phenomenon from Tm3+, Dy(3+ )to Sm3+ and Eu3+ is investigated. The photoluminescence properties of Y2WO6 (Tm3+, Dy3+, Sm3+ or Eu3+) phosphors renders them potential candidates for ultra-violet excited white light emitting diodes. (C) 2018 Elsevier BY. All rights reserved.