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Characterization of electrochemically deposited thin Mo-O-C-Se film layers

Dukstiene N., Tatariskinaite L., Andrulevicius M.

Materials Science Poland

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2010

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Vol. 28, No. 1

93--103

EN

The paper reports on the composition, morphology and optical properties of thin Mo-O-C-Se film electrodeposited onto SnO2-glass substrate (R = 292 ?/cm2). The composition of films was estimated based on X-ray photoelectron spectroscopy and Fourier transform infrared spectral analysis. Structural elements similar to molybdenum oxides and/or hydroxides, MoSe2, Se and SeO2 were identified on the surface and in the bulk of the electrodeposits. The studies of surface morphology by scanning electron microscopy and atomic force microscopy showed long-sized wires distributed over all the surface. The optical absorption studies revealed the films to be highly absorptive (104? cm-1) with a direct band transition and the bang gap energy of 1.75 eV.

2

Electrochemical Examination of the Influence of H2SeO3 on Molybdenum Electrodeposition on Tin Oxide Electrode from Aqueous Citrate Electrolyte

Dukstiene N., Tatariskinaite L.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 10

1715-1729

EN

Cyclic voltammetry and chronoamperometry have been used to evaluate the electrochemical reactions taking place under SnO2/glass electrode polarization in a solution of Na2MoO4, H2SeO3, sodium citrate (C6H5Na3O7) and in solutions consisting of their mixtures. According to our study, the presence of a small concentration ofH2SeO3 in the electrolyte is necessary to induce the reduction ofMoO4 2 ions. Experimental data support an assumption that the reduction ofMoO4 2 ions to molybdenum could occur when selenium nuclei are initially formed on the electrode. Eventually selenium nuclei induce the electrodeposition of molybdenum, giving finally thin Mo–Se film layers. AAS analysis confirms that in the potential interval between –1.0 and –1.2 V, thin films with a Mo/Se atomic ratio 0.63 and 0.57, respectively, are obtained.

3

Characterization of CuxS Layers Obtained by Adsorption-Diffusion Method on by Adsorption-Diffusion Method on Polycaproamide from K2S5O6 Solutions

Krylova V., Dukstiene N.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 9

1435-1447

EN

CuxS layers on polycaproamide, obtained by the adsorption-diffusionmethod, have been studied. These layers are formed when the ions of pentathionate (K2S5O6) sorbed into polycaproamide react with a solution of copper(I) salt. By X-ray diffraction studies it was determined that the CuxS layers obtained are of three phases, comprising covellite (CuS), geerite (Cu1.6S), anilite (Cu1.75S) and chalcocite (Cu2S). The concentration ratio of the phases depends on the period of polycaproamide sulfuration in a potassium pentathionate solution. Chalcocite prevails in the composition of CuxS film on PKA. The films were characterized by means of IR spectroscopy. IR absorption spectra were investigated in the region of the wavenumbers 200-1400 cm-1. The characteristic absorption maxima were found in the regions 242-243, 268-290, 339-384, 422-463, 538, 611-612, 879-929, 1018-1095, 1186-1224 cm-1 and assigned, respectively, to delta(S-S-S) and ni (Cu-S), gamma r(SO3), ni(S-S) and ni(Cu-S), delta as(O-S-O), delta s(O-S-O), ni (Cu-S), ni s(S-O) and ni as(S-O). Measurements of electrode potentials in CuSO4 solutions of different concentration have shown that the response time and stability of electrodes in Cu2+ ion solutions depend on the phase composition. Electrodes composed from Cu1.75S and Cu1.6S are not stable in CuSO4 solutions. The response time of a Cu2S electrode depends on concentration change. The change of the potential with an active Cu2+ ion concentration is linear in the range of 1.10-3-4.10-2mol_dm-3, the slope of the linear portion being 31.5mVper decade. The obtained experimental values have been compared with the theoretical values calculated on the basis of thermodynamic data.