Search results for "Electrode"
showing 10 items of 950 documents
Interface Solid-State Reactions in La0.8Sr0.2MnO3/Ce0.8Sm0.2O2 and La0.8Sr0.2MnO3/BaCe0.9Y0.1O3 Disclosed by X-ray Microspectroscopy
2019
The stability of the electrode/electrolyte interface is a critical issue in solid-oxide cells working at high temperatures, affecting their durability. In this paper, we investigate the solid-state chemical mechanisms that occur at the interface between two electrolytes (Ce0.8Sm0.2O2, SDC, and BaCe0.9Y0.1O3, BCY) and a cathode material (La0.8Sr0.2MnO3, LSM) after prolonged thermal treatments. Following our previous work on the subject, we used X-ray microspectroscopy, a technique that probes the interface with submicrometric resolution combining microanalytical information with the chemical and structural information coming from space-resolved X-ray absorption spectroscopy. In LSM/BCY, the …
Influence of pressure on ultrasonic cavitation activity in room temperature ionic liquids: An electrochemical study
2019
Abstract This paper provides proofs of the respective contributions of dissolved gases and solvent vapor on cavitation activity in sonoreactors. This activity can be detected by electrochemistry because the fluctuating events measured at the electrode surface are only linked to physical effects of cavitation. As ionic liquids present very low volatilities, their vaporization is reduced, and cavitation bubbles only depend on the presence of gases. Then, cavitation activity may be trigged by reactor atmosphere control. Applying severe depression within an irradiated ionic liquid medium contributes to removing dissolved gases, thus quenching cavitation activity. A specific sonoelectrochemical …
Amorphous semiconductor—electrolyte junction. Energetics at the a-WO3—electrolyte junction
1991
In order to elucidate the influence of thickness and amorphous structure on the kinetics of electron exchange with redox couples in solution, a critical re-examination of the energetics at the amorphous anodic WO3 films (a-WO3)—electrolyte junction has been performed, based on a recent theory of amorphous semiconductor (a-SC) Schottky barrier. The admittance study of the barrier performed in a large interval of electrode potential at changing frequency and film thickness allowed the determination of the energy levels as well as the distribution of localized electronic states within the mobility gap of the films. The new energetic picture derived is able to explain some features of the kinet…
Hybrid electrochemical/electrochromic Cu(II) ion sensor prototype based on PANI/ITO-electrode
2017
Abstract Conducting polymer polyaniline (PANI) based electrochromic films were electrochemically synthesized on indium tin oxide (ITO) covered glass electrodes and their electrochromic performances were investigated by spectroscopic methods before and after the incubation in Cu(II) ion containing aqueous solution. Chemical structure of synthesized PANI layer was evaluated by FTIR. The electrochromic performance of PANI film was determined by measuring of spectroscopic signals before and after the incubation of PANI film coated electrode in Cu(II) ion containing solution. During the change of potential, which was applied to PANI-modified electrode, the colour of PANI thin film turned from gr…
Relation between molecule ionization energy, film thickness and morphology of two indandione derivatives thin films
2016
Abstract Nowadays most organic devices consist of thin (below 100 nm) layers. Information about the morphology and energy levels of thin films at such thickness is essential for the high efficiency devices. In this work we have investigated thin films of 2-(4-[N,N-dimethylamino]-benzylidene)-indene-1,3-dione (DMABI) and 2-(4-(bis(2-(trityloxy)ethyl)amino)benzylidene)-2H-indene-1,3-dione (DMABI-6Ph). DMABI-6Ph is the same DMABI molecule with attached bulky groups which assist formation of amorphous films from solutions. Polycrystalline structure was obtained for the DMABI thin films prepared by thermal evaporation in vacuum and amorphous structure for the DMABI-6Ph films prepared by spin-coa…
Relating Measuring Signals From P O 2 Electrodes to Tissue P O 2: A Theoretical Study
1992
Organ surface P O 2 measurement by oxygen sensitive electrodes has proved to be an efficient tool for monitoring changes in tissue oxygenation status in a number of experimental and clinical situations. A parameter giving more direct information is the P O 2 distribution within tissue cells which, however, can only be assessed by more invasive methods. To date, a quantitative relation between P O 2 electrode measurements and P O 2 in tissue cells has not been established. Part of this problem lies in the fact that any surface electrode P O 2 measurement is not confined to tissue cells but rather represents some average over P O 2 values in a certain volume containing not only tissue cells b…
Electrochemical behaviour of Nafion®+cupromeronic phthalocyanine films
1999
Abstract The surface of indium tin oxide (ITO) and graphite+polymer composite electrodes can be modified by Nafion ® films containing a little amount of dispersed electroactive substances, such as phthalocyanines. This procedure allows electroanalytical information on the electroactive deposited substance to be obtained. The preparative methods of these type of modified electrodes are discussed from voltammetric results in this work. The proposed equivalent circuit explains the voltammetric differences between these electrodes. The Nafion ® net acts as a permeable membrane to the hydrogen ions. Besides, the presence of methylviologen within the Nafion ® film makes the electron transport thr…
Current rectification in a single molecule diode: the role of electrode coupling.
2015
We demonstrate large rectification ratios (> 100) in single-molecule junctions based on a metal-oxide cluster (polyoxometalate), using a scanning tunneling microscope (STM) both at ambient conditions and at low temperature. These rectification ratios are the largest ever observed in a single-molecule junction, and in addition these junctions sustain current densities larger than 10^5 A/cm^2. By following the variation of the I-V characteristics with tip-molecule separation we demonstrate unambiguously that rectification is due to asymmetric coupling to the electrodes of a molecule with an asymmetric level structure. This mechanism can be implemented in other type of molecular junctions u…
Study of the role of particle-particle dipole interaction in dielectrophoretic devices for biomarkers identification
2015
A three dimensional Coupled Monte Carlo-Poisson method has been used to evaluate the impact of particle-particle dipole interactions in the equilibrium distribution of a system of uncharged polarizable particles suspended in a static liquid medium under the action of an oscillating non-uniform electric field generated by polynomial electrodes. We compare the simulated distributions with experimental ones both for micro- (MDA-MB-231 breast tumor cells) and nano-(multiwall carbon nanotubes) particles. In both cases the equilibrium distributions near the electrodes are dominated by dipole interactions which locally enhance the DEP effect and promote long particles chains.
A nanostructured sensor of hydrogen peroxide
2017
Abstract A nanostructured electrochemical sensor of hydrogen peroxide was fabricated growing self-standing Pd nanowires (Pd NWs) into polycarbonate (PC) membranes through a simple metal galvanic deposition. Conditions of deposition were adjusted in order to attain 2–5 μm long Pd wires. Characterization of Pd-NWs was performed by scanning electrode microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Properties of the nanostructured sensor were studied by cyclic voltammetry and chronoamperometry in phosphate buffer—ethanol solution. Addition of pure ethanol to the test solution was essential in order to increase wettability of the nanostructures. Sensing features were comp…