The structure of synthesized samples was evaluated by X-ray powder diffraction with a Stoe powder diffractometer equipped with a position sensitive detector. Transmission electron microscopy (TEM) was made with Philips CM20 SuperTwin microscope operating at 200 kV.
Excitation spectra were recorded with a Spectra Pro 750 mono- chromator, equipped with Hamamatsu R928 photomultiplier. The excitation source – 450W Xenon arc lamp was coupled with 275 mm excitation monochromator. The emission spectra (Ar+/Kr+ laser ILM 120 kexc. = 488 nm, 567 nm, and HeNe laser JDSU kexc. = 632 nm) were measured at