Production and shaping of high performance phosphors by using the sol–gel process: Yttrium aluminum garnet (Y3Al5O12)

Luminescent Y3Al5O12:Tb3+ (YAG:Tb3+) phosphor thin films and powders have been successfully prepared by the sol–gel route from alkoxide precursors. Advanced coatings were produced by spray and dip-coating from stabilized sols. X-ray diffraction (XRD), attenuated total reflectance/Fourier transform infrared spectroscopy (ATR/FTIR) and atomic force microscopy (AFM) were used to investigate the structure and morphology of layers. YAG phases of high purity were obtained for both powders and films. AFM study revealed coatings of homogeneous topography, whatever the deposition technique. However, dip-coated samples exhibited a much smoother topography, characterized by a root mean square (rms) roughness much lower than that of spray-coated ones. Laser induced emission spectra and decay times of Tb3+ ions in a spray-coated film were recorded. Measurements exhibit the characteristic green emission of Tb3+. Effectiveness of the Tb3+ doped coatings under UV excitation is also illustrated by pictures.