TiO 2 nanoparticles doped with different concentrations of cobalt (4, 8, 12 and 16 %) were synthesized by sol-gel method at room temperature with appropriate reactants. In general, TiO 2 can exist in anatase, rutile, and brookite phases. In this present study, we used titanium tetra iso propoxide and 2-propanol as a common starting materials and the obtained products were calcined at 500°C and 800°C to get anatase and rutile phases, respectively. The crystalline sizes of the doped and undoped TiO 2 nanoparticles were observed with X-ray diffraction (XRD) analysis. The functional groups of the samples were identified by Fourier transform infrared spectroscopy (FTIR). From UV-VIS diffuse reflectance spectra (DRS), the band gap energy and excitation wavelength of doped and undoped TiO 2 nanoparticles were identified. The defect oriented emissions were seen from photoluminescence (PL) study. The spherical uniform size distribution of particles and elements present in the samples was determined using two different techniques viz., scanning electron microscopy (SEM) with energy-dispersive spectrometer (EDX) and transmission electron microscope (TEM) with selected area electron diffraction (SAED) pattern. The second harmonic generation (SHG) efficiency was also found and the obtained result was compared with potassium di hydrogen phosphate (KDP).

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Cerium-doped zinc sulfide nanorods with flower-shaped morphology have been successfully synthesized in air atmosphere through simple chemical precipitation method. The incorporation of Ce 3? was confirmed by X-ray diffraction and energy-dispersive spectrum. The doping of Ce 3? ions has significant influence on the optical properties of the synthesized rods. UVVis absorption spectroscopy measurements have shown that the absorption peak of doped ZnS was red shifted compared to undoped ZnS. Photoluminescence measurements reveal that luminescence intensity of Ce 3? was enhanced considerably by the energy transfer from ZnS. The existence of functional groups was identified using Fourier transform infrared spectrometer. Field emission scanning electron microscope results show a uniform growth pattern of the nanorods with flowerlike structure. High resolution transmission electron microscopy results showed that the doped ZnS nanocrystals are composed of uniform nanorods with average diameter of 22 nm and length of 140 nm. The thermal stability of the nanorods was confirmed using thermo gravimetric and differential thermal analysis.

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Herein, we suggest a simple chemical precipitation method for the preparation of bare and different levels of Zn doped MnO2 nanoparticles as electrodes for supercapacitors.