Mukherjee, Smita and Chakraborty, Sreeanta and Samanta, Aniruddha and Ghosh, Jiten and Mukhopadhyay, Anoop Kumar (2017) Band gap tuning in gold nanoparticle decorated TiO2 films: effect of Au nanoparticle concentration. Materials Research Express , 4 (6). Article No-065016 . ISSN 2053-1591

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Highly crystalline titanium dioxide (TiO2) and gold nanoparticle (Au NP) incorporated TiO2 films (with varying Au NP concentration), prepared by sol-gel route have been compared as regards their optical absorption spectra. Results indicated an increase in absorbance as well as systematic shift of the absorption edge towards the visible region, with increase in Au NP concentration, upto a critical concentration, beyond which a decrease in absorbance was observed. The optical band gap, calculated from the UV-Vis spectra, shows significant decrease (Delta = 0.14 eV) with respect to pristine TiO2, for this critical concentration (10% Au NP in TiO2 by volume), above which the decrease (Delta) was found to be less. The morphology of the composite film at this critical concentration revealed a homogeneous microstructure comprising particles of similar to 50 nm. The optimum band gap decrease was found to be associated with a structural change from rutile for the pristine to anatase-rutile mixed phase for the composite film. X-ray diffraction and transmission electron microscopy results indicated a reasonably good match of the lattice spacing for the optimum film. Preliminary current-voltage measurements indicated decrease in electrical resistivity of the optimum Au-TiO2 film, compared to that of its pristine counterpart.

Item Type: Article
Subjects: Engineering Materials
Depositing User: Bidhan Chaudhuri
Date Deposited: 29 Jan 2018 11:53
Last Modified: 29 Jan 2018 11:53

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