Bi(3+) and Eu(3+) Activated Luminescent Behaviors in Non-Stoichiometric LaO(0.65)F(1.7) Structure

Optical materials composed of La(1-)(p)(-)(q)Bi(p)Eu(q)O(0.65)F(1.7) (p = 0.001–0.05, q = 0–0.1) were prepared via a solid-state reaction using La(Bi,Eu)(2)O(3) and NH(4)F precursors at 1050 °C for two hours. X-ray diffraction patterns of the phosphors were obtained permitting the calculation of unit-cell parameters. The two La(3+) cation sites were clearly distinguished by exploiting the photoluminescence excitation and emission spectra through Bi(3+) and Eu(3+) transitions in the non-stoichiometric host lattice. Energy transfer from Bi(3+) to Eu(3)(+) upon excitation with 286 nm radiation and its mechanism in the Bi(3+)- and Eu(3+)-doped host structures is discussed. The desired Commission Internationale de l’Eclairage values, including emissions in blue-green, white, and red wavelength regions, were obtained from the Bi(3+)- and Eu(3+)-doped LaO(0.65)F(1.7) phosphors.