Tunable luminescent chromaticity of CaZnOS: Bi3+, Eu3+ with white emitting based on energy transfer

A series of Bi 3+ or Eu 3+ ion single doped and Bi 3+ and Eu 3+ co-doped CaZnOS phosphors were synthesized via high temperature solid state method. Under ultraviolet (UV) excitation, CaZnOS: Bi 3+ has an intense emission band ranged from 400 to 600 nm owing to the 3 P 1,0 → 1 S 0 transition of Bi 3+ . And CaZnOS: Eu 3+ shows superior red emissions due to the characteristic 5 D 0 → 7 F J ( J = 1, 2, 3, 4) transitions of Eu 3+ . Tunable emission chromaticity from cyan, white, yellow to red is obtained by regulating the proportion of Eu 3+ in CaZnOS Bi 3+ , Eu 3+ . The energy transfer mechanism from Bi 3+ to Eu 3+ was confirmed to be a quadrupole-quadrupole interaction based on the overlap of emission band of Bi 3+ and excitation band of Eu 3+ combined with the luminescent lifetime measurement. In addition, CaZnOS: 2.5 mol% Bi 3+ , 3 mol% Eu 3+ phosphor with optimized concentrations has standard white light chromaticity coordinates (0.315, 0.323) and activation energy about 0.372 eV, which reflects its potential application in ultraviolet-chip excited white light emitting diodes (W-LEDs).