engleski

Structure, microstructure and photoluminescence of nanocrystalline Ti-doped gahnite

A series of Ti-doped ZnAl2O4 (gahnite) samples with doping levels of 0, 1.8, 3.8, 5.4 and 11.6 at% Ti in relation to Al were prepared by a sol-gel technique. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), EPR spectroscopy, UV-vis reflectance spectroscopy and photoluminescence (PL) studies. Diffraction patterns indicated that all samples were nanocrystalline, with a spinel-type structure, space group Fd m. Titanium doping of gahnite caused an increase of unit-cell parameter and diffraction line broadening. The structure of samples was refined by the Rietveld method, simultaneously with the analysis of diffraction line broadening. TEM investigations confirmed that samples had spinel-type structure, and showed that samples contained evenly shaped particles of about 20 nm in size. Ti-doped samples exhibited strong absorption at wavelength <400 nm, and blue photoluminescence under excitation with λexc=308 nm.

transition metal alloys and compounds ; sol-gel processing ; crystal structure ; X-ray diffraction ; transmission electron microscopy ; luminescence

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