Nanosized Gd2O3:Eu3+ red phosphor is prepared using a template method from metal salt impregnated into a crystalline cellulose and is dispersed using a bead mill wet process. The driving force of the surface coating between Gd2O3:Eu3+ and mica is induced by the Coulomb force. The red phosphor nanosol is effectively coated on mica flakes by the electrostatic interaction between positively charged Gd2O3:Eu3+ and negatively charged mica above pH 6. To prepare Gd2O3:Eu3+-coated mica (Gd2O3:Eu/mica), the coating conditions are optimized, including the stirring temperature, pH, calcination temperature, and coating amount (wt%) of Gd2O3:Eu3+. In spite of the low luminescence of the Gd2O3:Eu/mica, the luminescent property is recovered after calcination above 600℃ and is enhanced by increasing the Gd2O3:Eu3+ coating amount. The Gd2O3:Eu/mica is characterized using X-ray diffraction, field emission scanning electron microscopy, zeta potential measurements, and fluorescence spectrometer analysis.

A3-2x/3Al1-zInzO4F: Eux3+ (A=Ca, Sr, Ba, x=-0.15, z=0, 0.1) oxyfluoride phosphors were simply prepared by thesolid-state method at 1050oC in air. The phosphors had the bright red photoluminescence (PL) spectra of an A3-2x/3Al1-zInzO4Ffor Eu3+ activator. X-ray diffraction (XRD) patterns of the obtained red phosphors were exhibited for indexing peak positionsand calculating unit-cell parameters. Dynamic excitation and emission spectra of Eu3+ activated red oxyfluoride phosphors wereclearly monitored. Red and blue shifts gradually occurred in the emission spectra of Eu3+ activated A3AlO4F oxyfluoridephosphors when Sr2+ by Ca2+ and Ba2+ ions were substituted, respectively. The concentration quenching as a function of Eu3+contents in A3-2x/3AlO4F:Eu3+ (A=Ca, Sr, Ba) was measured. The interesting behaviors of defect-induced A3-2x/3Al1-zInzO4-αF1-δphosphors with Eu3+ activator are discussed based on PL spectra and CIE coordinates. Substituting In3+ into the Al3+ positionin the A3-2x/3AlO4F:Eu3+ oxyfluorides resulted in the relative intensity of the red emitted phosphors noticeably increasing byseven times.