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Microwave assisted biosynthesis of rice shaped ZnO nanoparticles using Amorphophallus konjac tuber extract and its application in dye sensitized solar cells

Kumar P. N., Sakthivel K., Balasubramanian V.

Materials Science Poland

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2017

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Vol. 35, No. 1

111--119

EN

Rice shaped ZnO nanoparticles have been synthesized for the first time by a biological process using Amorphophallus konjac tuber extract and used as a photoanode in a dye sensitized solar cell. The glucomannan present in aqueous tuber extract acted as a reducing agent in the synthesis process, further it also acted as a template which modified and controlled the shape of the nanoparticles. The synthesized nanoparticles were dried by microwave irradiation followed by annealing at 400 °C. The FESEM and TEM images confirmed that the synthesized ZnO nanoparticles had rice shaped morphology. Furthermore, the X-ray diffraction studies revealed that the prepared ZnO nanoparticles exhibited wurtzite phase with average particle size of 17.9 nm. The UV-Vis spectroscopy studies confirmed the value of band gap energy of biosynthesized ZnO nanoparticles as 3.11 eV. The photoelectrodes for dye sensitized solar cells were prepared with the biosynthesized ZnO nanoparticles using doctor blade method. The photoelectrode was sensitized using the fruit extract of Terminalia catappa, flower extracts of Callistemon citrinus and leaf extracts of Euphorbia pulcherrima. The dye sensitized solar cells were fabricated using the sensitized photoelectrode and their open circuit voltages and short circuit current densities were found to be in the range of 0.45 V to 0.55 V and 5.6 mA/cm2 to 6.8 mA/cm2, respectively. Thus, the photovoltaic performances of all the natural dye sensitized ZnO solar cells show better conversion efficiencies due to the morphology and preparation technique.

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Effect of deposition temperature on structural, optical and electrical properties of copper bismuth sulphide (CuBiS2) thin films deposited by chemical bath deposition

Balasubramanian V., Kumar P. N., Sengottaiyan D.

Materials Science Poland

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2017

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Vol. 35, No. 2

329--334

EN

The effect of deposition temperature on the structural, optical and electrical properties of copper bismuth sulphide (CuBiS2) thin films deposited by chemical bath deposition onto glass substrates at different deposition temperatures (40 °C, 50 °C, 60 °C and 70 °C) for 5 hours deposition time period was investigated. The obtained films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and optical absorption spectra. All deposited films were polycrystalline and had an orthorhombic structure. Their grain size had changed with deposition temperature and their compositions were nearly stoichiometric. The optical band gap value was decreased from 2.44 eV to 2.33 eV with increasing the film thickness. Electrical parameters such as mobility and type of electrical conduction were determined from the Hall effect measurements. They showed that the obtained films have n-type conductivity and mobility values of the copper bismuth sulphide (CuBiS2) films have changed with deposition temperature.

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Investigation of sol-gel processed CuO/SiO2 nanocomposite as a potential photoanode material

Tenkyong T., Bachan N., Raja J., Kumar P. N., Shyla J. M.

Materials Science Poland

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2015

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Vol. 33, No. 4

826--834

EN

Synthesis and characterization of a highly efficient photoconductive nanocomposite comprising of two common metal oxides: copper oxide (CuO) and silicon dioxide (SiO2>/sub>) are being reported in this paper. The CuO/SiO2 nanocomposite has been synthesized using a cost-effective and facile sol gel route. The structural, chemical and optical properties of the prepared samples have been studied using various characterization techniques. The UV-Vis analysis revealed better absorption in the case of the nanocomposite as compared to its parent materials. X-ray diffraction (XRD) analysis has been employed to determine the structural formation of the nanocomposite and the crystallite size with the use of Scherrer's formula. The photo conductivity study of the sample showed enhanced photocurrent in the case of nanocomposite as compared to its single components, thus, presenting it as a potential candidate for solar cell applications, especially as photoanode material in the dye-sensitized solar cells (DSSC).