Amrita Biswas

Solution-processed Cu2XSnS4 (X = Fe, Co, Ni) photo-electrochemical and thin film solar cells on vertically grown ZnO nanorod arrays

This article presents the photo-electrochemical and photovoltaic performances of solution processed Cu2XSnS4 (X = Fe, Co, Ni) thin films on ZnS coated vertically aligned ZnO nanorod (NR) arrays for the first time. The optical, structural and electrical properties of all the synthesized structures were investigated using various characterization techniques. The electrocatalytic activities of the superstrate structures were characterized by taking cyclic voltammetry (CV) measurements and performing electrochemical impedance spectroscopy (EIS) analyses. Furthermore, the photovoltaic performances of the devices with architecture ITO/ZnO-NRs/ZnS/Cu2XSnS4/Au were investigated under AM 1.5 illumination condition. The thin film solar cells with Cu2FeSnS4 (CFTS), Cu2CoSnS4 (CCTS) and Cu2NiSnS4 (CNTS) photoactive layers exhibited power conversion efficiency (PCE) values of 2.73%, 3.23% and 2.71% respectively. All the devices exhibit good electrochemical as well as photovoltaic performance under illuminations and have shown potential to fabricate nontoxic solution processed high efficient devices.

Photo-electrochemical properties and electronic band structure of kesterite copper chalcogenide Cu2–II–Sn–S4 (II = Fe, Co, Ni) thin films

Herein, we report a spin coating route for the deposition of multifunctional quaternary copper chalcogenide Cu2–II–Sn–S4 (II = Fe, Co and Ni) thin films on ITO glass substrates. The surface morphology of the thin films is a uniform porous like structure with an average film thickness of 1.5 μm. The formation of single phase Cu2FeSnS4 (CFTS), Cu2CoSnS4 (CCTS) and Cu2NiSnS4 (CNTS) thin films was confirmed by Raman spectroscopy, which reveals two principal Raman peaks of the A1 phonon mode. Due to the presence of the d6, d7 and d8 electronic configurations within Fe2+, Co2+ and Ni2+ ions, respectively, all the materials show a spin magnetic moment per ion of 3.33 μB, 2.45 μB and 1.31 μB for CFTS, CCTS and CNTS, respectively, as described by the electronic band structure calculation (WIEN2k code). All the thin films have estimated band gap values of 1.87 eV, 1.57 eV and 1.74 eV, respectively, with enhanced photocurrent properties and electrocatalytic activity. Significantly improved charge transfer properties of the thin films were observed from electrochemical impedance spectroscopy analysis under dark and visible light illumination conditions. These thin films are promising for use in photoelectrochemical and solar cell applications.

Effect of chemical modification of a natural polysaccharide on its inhibitory action on mild steel in 15% HCl solution

Abstract Many of the synthetic corrosion inhibitors being used currently, are toxic and therefore research for developing environmentally benign corrosion inhibitors is of great importance. Inhibitors such as natural polysaccharides of plant origin are popular due to its non-toxic nature. Here, the toxicity of a natural polysaccharide, guar gum, and its modified form, cationic guar gum was studied and their inhibitory effects were investigated by gravimetric, electrochemical and surface morphology studies. Both the inhibitors are found to be effective and their adsorption on metal is in accordance with the Langmuir adsorption isotherm. Experimental results are in consonance with the results of quantum chemical calculations by density functional theory.