Search results for " electrochemical impedance spectroscopy"

showing 4 items of 24 documents

Tuning of solid state properties of Al-Ta mixed oxides

2014

Settore ING-IND/23 - Chimica Fisica Applicatasolid state properties Al-Ta mixed oxides Photoelectrochemistry Electrochemical Impedance Spectroscopy
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A critical analysis of the theory of amorphous semiconductor Schottky barrier for oxides

2014

Settore ING-IND/23 - Chimica Fisica Applicatatheory of amorphous semiconductor Schottky barrier oxides electrochemical impedance spectroscopy
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The origin of slow electron recombination processes in dye-sensitized solar cells with alumina barrier coatings

2004

We investigate the effect of a thin alumina coating of nanocrystalline TiO2 films on recombination dynamics of dye-sensitized solar cells. Both coated and uncoated cells were measured by a combination of techniques: transient absorption spectroscopy, electrochemical impedance spectroscopy, and open-circuit voltage decay. It is found that the alumina barrier reduces the recombination of photoinjected electrons to both dye cations and the oxidized redox couple. It is proposed that this observed retardation can be attributed primarily to two effects: almost complete passivation of surface trap states in TiO2 that are able to inject electrons to acceptor species, and slowing down by a factor of…

Solar cellsCharge injectionPassivationAbsorption spectroscopyIon recombinationThin filmsAluminaAnalytical chemistryGeneral Physics and AstronomyPhotochemistryTime resolved spectraTitanium compounds ; Alumina ; Nanostructured materials ; Semiconductor materials ; Thin films ; Solar cells ; Ion recombination ; Dyes ; Charge exchange ; Charge transfer states ; Charge injection ; Electrochemical impedance spectroscopy ; Time resolved spectraSemiconductor materials:FÍSICA [UNESCO]Ultrafast laser spectroscopyCharge exchangeThin filmSpectroscopyDyesQCChemistryUNESCO::FÍSICANanostructured materialsAcceptorDielectric spectroscopyDye-sensitized solar cellTACharge transfer statesTitanium compoundsElectrochemical impedance spectroscopy
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PBI-based composite membranes for polymer fuel cells

2010

Abstract In the present study poly(2,2-(2,6-pyridin)-5,5-bibenzimidazole) was used for the preparation of novel MEAs for high-temperature polymer fuel cells (HT-PEMFCs). We prepared hybrid materials with two types of silica fillers in order to increase the MEA performances using this polymer. The membranes were characterized in terms of their microstructure and thermal stability. Cell operation tests and Electrochemical Impedance Spectroscopy were used for the characterization of the MEAs. A maximum power density of about 80 mW cm−2 was obtained at 300 mA cm−2 by using an imidazole-modified silica filler. The EIS technique showed that the fillers chiefly help to reduce the charge transfer r…

chemistry.chemical_classificationProton exchange membrane PBI Electrochemical Impedance SpectroscopyFiller (packaging)Materials scienceRenewable Energy Sustainability and the EnvironmentAnalytical chemistryEnergy Engineering and Power TechnologyProton exchange membrane fuel cellPolymerMicrostructureDielectric spectroscopyMembranechemistryChemical engineeringProton exchange membrane PBI Electrochemical Impedance SpectroscopyThermal stabilityElectrical and Electronic EngineeringPhysical and Theoretical ChemistryHybrid material
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