• AKBAR ESHAGHI

Articles written in Bulletin of Materials Science

• Photoinduced properties of nanocrystalline TiO2 sol–gel derived thin films

In this paper, nanostructure TiO2 thin films were deposited on glass substrates by sol–gel dip coating technique. X-ray diffraction and Fourier transform infrared spectroscopy were used to determine film behaviour. The super-hydrophilicity was assessed by contact angle measurement. Photocatalytic properties of these films were evaluated by degradation of methylene blue under UV irradiation. The XRD pattern of TiO2 powder samples confirmed the presence of polycrystalline anatase phase with a crystal size of 17 nm. The results indicated that UV light irradiation had significant effect on super-hydrophilic and photocatalytic properties of TiO2 thin films.

• Investigation of superhydrophilic mechanism of titania nano layer thin film—Silica and indium oxide dopant effect

In this paper, TiO2–SiO2–In2O3 nano layer thin films were deposited on glass substrate using sol–gel dip coating method. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle measurements were used to evaluate chemical structure, surface composition, hydroxyl group contents and superhydrophilicity of titania films. FTIR result indicated that Si–O–Si, Si–O–Ti and Ti–O–Ti bands formed in TiO2–SiO2–In2O3 sample. According to XPS, the hydroxyl content for TiO2, TiO2–SiO2 and TiO2–SiO2–In2O3 films was calculated as 11.6, 17.1 and 20.7%, respectively. The water contact angle measurements indicated that silica and indium oxide dopant improved the superhydrophilicity of titania nano film surface especially in a dark place. The enhanced superhydrophilicity can be related to the generation of surface acidity on the titania nano film surfaces. In the present state, superhydrophilicity is induced by the simultaneous presence of both Lewis and Bronsted sites.

• Effect of crystal structure on photoinduced superhydrophilicity of copper grafted TiO2 nanostructure thin film

In this work, copper grafted titanium dioxide (rutile and brookite) thin films were deposited on glass substrates using the dip-coatingmethod. Field emission scanning electron microscopy and X-ray photoelectron spectroscopy were used to evaluate the surface morphology and properties of the film surfaces. The water contact angle on the film surfaces during irradiation and storage in a dark place was measured by a contact angle analyser. The results indicate that copper grafted titanium dioxide brookite thin film showed higher hydrophilicity than copper grafted titania rutile thin film.

• Effect of TiO2–graphene nanocomposite photoanode on dye-sensitized solar cell performance

In this research work, graphene–TiO2 photoanodes with various graphene concentrations (0, 0.5, 1, 1.5 and 2 wt%) were deposited on fluorine tin oxide glass substrates as working electrodes for dyesensitized solar cells. The structure, morphology, surface composition and dye adsorption of the photoanodes were investigated by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy and UV–VIS–NIR spectroscopy, respectively. The photocurrent–voltage characteristics of the dye-sensitized solar cells were examined using a solar simulator. The results indicated that the dye adsorption on photoanode surfaces increases with the increase in the graphene content. In addition, dye-sensitized solar cells efficiency increases with the increase in the graphene content to 1.5 wt% and then decreased. The efficiency of the dyesensitized solar cell, based on the TiO2–1.5 wt% graphene nanocomposite, increased by 42% with respect to the pristine sample.

• Investigation of chemical etching and surface modification effect on the superhydrophobic, self-cleaning and corrosion behaviour of aluminium substrate

In this study, superhydrophobic surfaces were fabricated on aluminium substrates by chemical etching method and surface modification with perfluorooctyl trichlorosilane (PFTS). The superhydrophobic surface of the aluminium substrate was synthesized by two-step process: first, the roughness on the aluminium surface was created by the chemical etching method. Then, the surface energy of the rough aluminium substrate was reduced by immersion in the PFTS solution. The surface wettability was measured by a droplet contact angle measurement. The morphology and chemical composition of the surface were detected by field emission scanning electron microscope and attenuated total reflection-Fourier transform infrared methods, respectively. The self-cleaning properties of the coated and bare aluminium substrates were investigated. Corrosion behaviour of the samples was evaluated using Tafel polarization and salt spray methods. The contact angle measurement results showed that the surface roughness due to chemical etching reduced the contact angle on the aluminium substrate to 24°and after surface modification, the contact angle increased to 157°. In the Tafel polarization test, after creating a superhydrophobic surface, the corrosion current density and corrosion potential of the aluminium substrate reached from 94.3 to 28.82 (${\mu}$A cm$^{-2}$) and -0.695 to -0.68 V, respectively. The superhydrophobic aluminium surface showed self-cleaning effect.

• # Bulletin of Materials Science

Volume 46, 2023
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020