Dual-emissions with energy transfer from the phosphor Ca14Al10Zn6O35:Bi3+,Eu3+ for application in agricultural lighting

Bi3+ and Eu3+ co-activated Ca14Al10Zn6O35 (CAZO) phosphors were synthesized by a solid state sintering method. X-ray diffraction (XRD), scan electron microscopy (SEM), photoluminescence (PL) and decay studies were employed to characterize the as-prepared phosphor samples. A dual-emission composed of blue and red luminescence is observed in Bi3+ and Eu3+ co-activated CAZO phosphors, which has potential application in artificial lighting to improve the plant growth. The highest intensities of emissions of CAZO:Bi3+ and CAZO:Bi3+,Eu3+ are obtained at the concentration of Bi3+ at 0.5 mol% and 1.0 mol%, respectively. The overall luminescence color can be tunable from blue, purple, to red by changing the molecular ratio of Bi3+ to Eu3+. The mechanism of energy transfer from Bi3+ to Eu3+ has been demonstrated by decay times of Bi3+ emissions which are varied with Eu3+ content doped in host lattice. The efficiency of energy transfer from Bi3+ to Eu3+ increases with the increase of Eu3+ concentration, which leads to that the internal quantum yields (QY) of both Bi3+ and Eu3+ co-activated CAZO are higher than either of Bi3+ or Eu3+ singly doped phosphor.