Structural and optical characterizations of sol-gel derived europium doped YAG materials: powders and films

Sol-gel route has been successfully used to obtain pure Y3Al5O12 and Y3Al5O12:Eu3+ powders and films. Advanced YAG coatings were achieved by two techniques, the spray and dip-coating methods, giving rise to different characteristics and properties. The materials structure and microstructure were analyzed by means of X-ray diffraction and scanning electron microscopy. It has been shown that sol-gel processed YAG powders crystallize around 900degreesC whereas a temperature much higher is necessary to obtain this compound by solid state synthesis (approximate to 1500degreesC). Additionally the surface of the films was observed by atomic force microscopy. Eventually, laser induced luminescence spectra, as well as luminescence decays of Eu3+ ions show undoubtedly the spectral features of a Eu3+ emitting centre embedded in a unique site of D-2 symmetry.