Preparation and luminescent properties of tunable polychromatic phosphors CaNaB5O9: RE3+(RE = Dy, Eu, Tb)

Abstract A series of CaNaB5O9: RE3+ (RE = Dy, Eu, Tb, Tb/Eu, Dy/Eu) phosphors were prepared by the traditional high temperature solid state method. The crystal structure, morphology and luminous properties were characterized by powder X-ray diffraction, scanning electron microscopy and fluorescence spectra, respectively. The influence of rare earth ion doping concentration on the luminescence performance of samples was discussed. The optimal doping concentrations of Dy3+, Eu3+ and Tb3+ were 1 mol%, 15 mol% and 5 mol%, respectively. Under certain wavelength excitation, the samples CaNaB5O9: Dy3+, CaNaB5O9: Eu3+ and CaNaB5O9: Tb3+ can emit white light, red light and green light respectively. Under the near ultraviolet excitation of 369 nm, Ca1-x-yNaB5O9: xTb3+, yEu3+ phosphors can effectively transfer the excitation energy from Tb3+ to Eu3+. The luminous color changes gradually from green to yellow. Under the excitation of 393 nm, the emission spectra of CaNaB5O9: Dy3+, Eu3+ phosphors show the typical transition emission of Dy3+ and Eu3+. The red emission from energy transition of Eu3+ adds red light to the white emission of Dy3+ and decrease the color temperature. The results show that the sample CaNaB5O9: RE3+ (RE = Dy, Eu, Tb) can be the candidates of color-tunable phosphors for W-LEDs.