STRUCTURAL AND RAMAN SPECTROSCOPIC CHARACTERIZATION OF C-TIO_2 NANOTUBES SYNTHESIZED BY TEMPLATE ASSISTED SOL-GEL TECHNIQUE

摘要

It is of great importance to find ways of improving the charge transport within titanium dioxide nanotubes (TNTs) which will in turn decrease electron-hole pair recombination and subsequently increase the cell efficiency of the dye sensitized solar cells (DSSC). High electron mobility in TNTs relies on the morphology, surface defects and consistence in the crystalline composition. These factors are closely related to the preparation conditions. In this regard this work focuses on synthesis and structural characterization of carbon doped titanium dioxide nanotube. Un-doped and carbon doped titanium dioxide nanotubes (C-TNTs) were synthesized using a template-assisted sol-gel technique employing titanium tetra butoxide precursor and oxalic acid as the dopant. SEM, XRD, and Confocal Raman spectroscopy (CRS) was used to evaluate the morphological and structural properties of the as synthesized TNTs. SEM analysis has revealed that the morphology of TNTs prepared change with introduction of carbon dopant. SEM-EDX spectra has revealed the presence of Ti peaks at 0.45 and 4.9 keV corresponding to Kα1 and Kβ1 emission line respectively. Oxygen exhibits a signal at 0.5 keV corresponding to Kα1 emission line. XRD analysis has revealed the presence of a mixed Anatase-Brookite phase with diffraction peaks at 2θ angles of 25.49°, 38.11°, 40.60° 48.14°, 54.58°, 63.00°, 70.11° and 75.66°. CRS large area scan in the XY direction has revealed the presence of Raman active modes at 153.19 cm~(-1), 205.62 cm~(-1), 328.33 cm~(-1), 404.55 cm~(-1), 523.26 cm~(-1), 523.26 cm~(-1) and 648.69 cm~(-1) belonging to a mixed Anatase-Brookite phase. CRS depth profiling in the XZ direction has also validated the presence of a mixed Anatase-Brookite phase with Raman Active modes at 153.19 cm~(-1), 208.87 cm~(-1), 404.55 cm~(-1), 523.26 cm~(-1) and 648.55 cm~(-1).