In this study Cu 2+ +Eu 3+ co-doped ZnO(ZnO/Cu 2+ +Eu 3+ ) solid solution powders were synthesized by solution combustion method using as oxidant agent zinc nitrate hexahydrate and as fuel urea; the Cu 2+ concentrations were 0, 1, 2, 3, 10, and 20 %Wt; the Eu 3+ ion concentration was fixed in 3%Wt. The samples after were annealed at 900˚C by 20 h in air. The structural results showed the largely presence of a wurtzite solid solution of Cu 2+ +Eu 3+ doped ZnO, at high Cu 2+ doping CuO and Eu 2 CuO 4 phases are also present. Morphological properties were analyzed using scanning electron microscopy (SEM) technique. However it is important to remark that the Cu 2+ ions suppress the Eu 3+ ion photoluminescence (PL) by means of an overlap mechanism between Cu 2+ absorption band and Eu 3+ emission band (e.g. 5 D 0 → 7 F 2 ) of the Eu 3+ emission spectra.
Monodisperse ZnO solid spheres nanostructures were synthesized and deposited on Si (100) silicon substrates by the hexamethylenetetramine (HMTA)-assisted hydrothermal method at high temperature (200˚C). In this case the HMTA is used as structure directing agent (SDA) to growth of the ZnO solid spheres. The source material used was zinc nitrate hexahydrate under a chemical reaction of hydrolysis-condensation of the Zn 2+ salt aqueous solution. The structure and morphology of the ZnO solid spheres were studied by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Furthermore, the photoluminescence (PL) of the ZnO solid spheres was measured to optical characterization of the product. The remarkable influence of the HMTA as structure directing agent and the reaction temperature to the formation of the solid spheres nanostructures is demonstrated.
In this work, ZnO, Ce 3+ doped ZnO (ZnO/Ce 3+) and Cu 2+ + Ce 3+ co-doped ZnO (ZnO/Cu 2+ + Ce 3+) solid solutions powders were synthesized by a solution combustion method maintaining the Ce 3+ ion concentration constant in 3%Wt while the Cu 2+ ion concentration was varied in 1, 2, 3, 10 and 20%Wt. After its synthesis, all the samples were annealed at 900˚C by 24 h. The ZnO, ZnO/Ce 3+ and ZnO/Cu 2+ + Ce 3+ powders were structurally characterized using X-ray diffraction (XRD) technique, and the XRD patterns showed that for pure ZnO, Cu 2+ undoped ZnO/Ce 3+ and ZnO/Ce 3+ doped with the Cu 2+ ion, the three samples exhibited the hexagonal wurtzite ZnO crystalline structure. However, the morphology and particle size of both samples were observed by means of a scanning electron microscopy (SEM); from SEM image, it is observed that the crystallites of both samples are agglomerated forming bigger amorphous particles with an approximate average size of 1 μm. In addition, the photoluminescence of the ZnO, Ce 3+ doped ZnO and Cu 2+ + Ce 3+ doped ZnO samples was measurement under an illumination of 209 nm wavelength (UV region): for the ZnO/Ce 3+ sample, your emission spectrum is in the visible region from blue color until red color; the UV band of the ZnO is suppressed. The multicolor emission visible is attributed to the Ce 3+ ion photoluminescence, while for the ZnO/Cu 2+ + Ce 3+ , its emission PL spectrum is quenching by the Cu 2+ ion, present in the ZnO crystalline.
After the synthesis process all the samples were annealed at 900˚C by 24 h. The pure ZnO, ZnO: Ce 3+ and ZnO/Cu 2+ + Ce 3 powders were structurally characterized using X-ray diffraction (XRD) technique, the XRD patterns showed that for either undoped and doped with the Cu 2+ ion both exhibited the hexagonal wurtzite ZnO crystalline structure, also the diffraction peaks of both samples types showed a little change toward lesser angles. The morphology and particle size of the samples were observed by means of a scanner electron microscopy (SEM); from SEM imagen is observed that the crystallites of the samples are agglomerated forming cage-like hollow structures caused by the combustion process. The cage-like structures have approximate size of 800 nm. In addition, the photoluminescence of pure ZnO, ZnO: Ce 3+ and ZnO: Cu 2+ + Ce 3+ compounds was measurement as a function of Cu 2+ ion concentration under a excitation wavelength of 378 nm in the UV region. As an important result, it is observed that by Auger phenomena of non-radiative recombination, the UV emission of the ZnO is quenching.
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