Indium Tin Oxide Conductive Glass Research Articles

New fabrication technique of conductive polymer/insulating polymer composite films and evaluation of biocompatibility in neuron cultures

Poly(vinyl alcohol), PVA, produces a flexible composite polymer film with electrical, optical and electrochemical properties very similar to those of polypyrrole (PPy). The rate of electrochemical polymerization depends on the diffusion rate of the electrolyte across the PVA film to the indium tin oxide (ITO) electrode. In particular, a solvent with a hydrophilic nature easily penetrates into the PVA film. By applying this new process, we demonstrate a unique method of forming an electrically conductive pattern in PVA film. It will be possible to develop electrodes for electrical stimulation of the nervous system using the conducting polymer, PPy. Then, by applying a similar technique, we fabricated poly(3,4-ethylenedioxythiophene), PEDOT/PVA, composite films and investigated their basic electrochemical properties. Moreover, in this study, in order to develop a novel cell-culture system which makes it possible to communicate with cultured cells, fibroblasts were cultured on PPy- and PEDOT-coated ITO conductive glass plates for 7 days. The result reveals that the PPy and PEDOT films support the secretory functions of the cells cultured on its surface. The PPy- and PEDOT-coated electrodes may be useful to culture the cells on.

Preparation and photoelectrocatalytic activity of Pt(TiO2)–TiO2 hybrid films

A novel platinised TiO2 film, Pt(TiO2)–TiO2, was prepared by a two-step procedure in which TiO2 as a ‘binding layer’ was first loaded on ITO (indium–tin oxide) conductive glass plates, and then the platinised TiO2 particles in the suspension was dip-coated on the TiO2 film. The resultant hybrid film was characterized by X-ray reflection diffraction, scanning electron microscope, diffuse reflectance spectra and photoelectrochemical measurement. The experimental results showed that the Pt(TiO2)–TiO2/ITO hybrid film not only was much more stable than the single Pt(TiO2)/ITO film but also possessed rather high photocatalytic and photoelectrocatalytic activities compared with the pure TiO2/ITO film. With respect to formic acid solution, the chemical-oxygen-demand removal efficiency of photoelectrocatalytic oxidation for Pt(TiO2)–TiO2/ITO film is apparently higher than that of photocatalytic and photoelectrocatalytic oxidation of TiO2/ITO film, respectively.

Electrochemical charging and electrocatalysis at hybrid films of polymer-interconnected polyoxometallate-stabilized carbon submicroparticles

Using the layer-by-layer technique, carbon submicroparticles, that have been modified and stabilized with monolayers of Keggin-type phosphododecamolybdate (PMo12O 40 3− ), can be dispersed in multilayer films of organic polymers, poly(3,4-ethylenedioxythiophene), i.e., PEDOT, or poly(diallyldimethylammonium) chloride, i.e., PDDA, deposited on glassy carbon or indium-tin oxide conductive glass electrodes. The approach involves alternate treatments in the colloidal suspension of PMo12O 40 3− -covered carbon submicroparticles in the solution of monomer, 3,4-ethylenedioxythiophene or in solution of PDDA polymer. Electrostatic attractive interactions between anionic phosphomolybdate-modified carbon submicroparticles and cationic polymer layers permit not only uniform and controlled growth of the hybrid organic–inorganic film but also contribute to its overall stability. The system composed of PMo12O 40 3− -covered carbon submicroparticles dispersed in PEDOT is characterized by fast dynamics of charge transport and has been used to construct symmetric microelectrochemical redox capacitor. The PDDA-based system has occurred to be attractive for electrocatalytic reduction of hydrogen peroxide.

Mechanisms of pulse response and differential response of bacteriorhodopsin and their relations.

Bacteriorhodopsin (BR) films are oriented and deposited on indium tin oxide conductive glass by using electrophoretic sedimentation and Langmuir-Blodgett methods to construct sandwich-type photocells, respectively. The pulse response photoelectric signal of the BR photocell under pulsed laser and the differential response photoelectric signal under irradiation of interval light are measured. The origins of these two types of photoelectric responses and their correlations are analyzed. The pulse response signal initiates from the ultrafast charge separation of the retinal and the proton translocation followed by the deprotonation and reprotonation of the Schiff base and its surrounding amino acids. This is a quick response and is the preceding reaction of the differential response. The differential response signal is caused by the charging and discharging of the continuous proton current of the BR light-driven proton pump at light-on and light-off, which is a slow process. The differential response is related to not only the construction of the BR photocell but also the coupling mode of measurement. To observe the differential response signal, the BR photocell must have large enough B3 and B3' components in its pulse response as well as an alternative coupling mode to measure it.

A morphological study of polypyrrole films grown on indium-tin oxide conductive glass

In this study a detailed examination was carried out of variables that control the winkle morphology observed in p-toluenesulfonate doped polypyrrole films formed by electropolymerization on tin-doped indium oxide (ITO) coated glass using either methanol/water or water alone as solvents. Results are in agreement with an earlier study in which the porous nature of the substrate was identified as the most influential of the factors controlling the morphology. Other factors found to be important included: nature and size of the dopant ions, solvent, and concentrations of pyrrole and dopant. Examination of still-moist free-standing conductive films by light microscopy demonstrated that the wrinkles are not an artifact due to post-deposition shrinkage.

Morphology of polypyrrole films grown in thin-layer cells and on indium-tin oxide conductive glass

Examination by atomic force microscopy and scanning electron microscopy of the non-conducting substrate poly(methyl methacrylate) and the polypyrrole free-standing film formed at its surface in a thin-layer cell has led to an understanding of how such films may be formed. A mechanism is proposed for the origin of the wrinkle morphology observed in thin-layer cells under certain conditions, and attention is drawn to its similarity to the morphology of polypyrrole films formed on indium—tin oxide glass electrodes. In both cases it is proposed that the porous surface of the substrate on which the film grows acts as a template for nucleation sites.