Enhanced effect of co-doping of Ln3+ on the luminescent properties of BaSiO3:Eu3+ red phosphors

Abstract

In this work, Ba1-xSiO3:xEu3+ and Ba0·84SiO3:0.08Eu3+,0.08Ln3+（Ln = La, Y or Gd）series phosphors are obtained by calcining the precursors pre-synthesized via chemical co-precipitation method. The XRD patterns demonstrate the main phase is a chain silicate BaSiO3 formed by (SiO3)2- groups and Ba2+ ions with monoclinic crystal. Under the monitoring of 616 nm emission, the PLE spectra of Ba1-xSiO3:xEu3+ phosphors consist of several peaks at 246 nm, 320 nm, 363 nm, 382 nm, 393 nm, 414 nm, 464 nm and 535 nm with the strongest intensity at 393 nm, while four emission peaks located at 591 nm, 616 nm, 654 nm and 705 nm are found under activation at 393 nm, attributed to the 5D0→7Fj（j = 1,2,3,4）transition of Eu3+ ions. The highest emission peak appears at 616 nm in the case of 8 mol% Eu3+ doping. Although the emission intensity of the phosphors decreases gradually with the temperature increasing, it can maintain at 43.4% of that at room temperature even up to 250 °C. After co-doped with La3+，Y3+ or Gd3+ ions, the emission intensity of the phosphors at 616 nm is increased by 1.31, 1.32 or 1.75 times as a result of strengthening the crystal field, and the fluorescence lifetime is prolonged from 1.29 ms to 1.59 ms after co-doped Gd3+, ascribed to an energy transfer process of Gd3+→Eu3+. All these indicate the red phosphor has the potential in application for the white LEDs under the ultraviolet excitation.