Preparation and characterization of palladium-doped titanium dioxide for solar cell applications

The syntheses of TiO2 and Pd/TiO2 nanoparticles were carried by hydrolysis of alkoxide precursors using the reverse micelles method using titanium tetrabutoxide and palladium acetylacetonate as precursor metals. The method was modified by precipitation with the addition of n-butanol and then washed with an ethanol/water solution at a ratio of 1:1. Morphological characterization was performed by scanning electron microscopy and structural by X-ray diffraction and spectroscopy of Raman scattering. Electrical characterization was performed by impedance spectroscopy and the optical energy gap was determined from transmittance measurements Tauc plot fittings. The material was characterized by a suspension of spherical nanoparticles on the order of 100 nm confirmed by Scanning electron microscopy analysis. They also presented good ionic conductivity as indicated by impedance spectroscopy. Raman spectroscopy showed a systematic frequency shift to the left together with peak broadening as the amount of palladium incorporated onto TiO2 increases, which is characteristic of mesoscopic grains. X-ray diffractograms were carried with washed and dried powder samples and showed a mixture of anatase and brookite phases, with anatase as the predominant one.