Search results for "electrochromism"
showing 10 items of 50 documents
Electrochromic Devices Incorporating Cr Oxide And Ni Oxide Films:
2000
Abstract Transparent films of Cr oxide and Ni oxide were made by reactive DC magnetron sputtering in Ar+O2+H2. They displayed anodic electrochromism with charge capacities similar to that of W oxide. Cr oxide was stable in acidic environments, while Ni oxide was stable in basic environments. Electrochromic devices were made with pristine Cr oxide or Ni oxide films operating in conjunction with W oxide and a proton conducting electrolyte. Of the two oxides, Cr oxide film allowed device operation at a lower voltage span, while the device with Ni oxide film yielded a higher transmittance in the bleached state, a larger absorptance modulation, and a more neutral color.
ELECTRODEPOSITION OF NOVEL POLY(NAPHTHALENEDIIMIDE-QUATERTHIOPHENE) THIN FILMS AND APPLICATIONS IN PLASTIC OPTOELECTRONICS DEVICES
2013
A novel symmetric naphthalenediimide-quaterthiophene derivative (NDIT4d) has been polymerized on different substrates including glassy carbon and ITO/PET electrodes by means of electrochemical methods. XPS and UV-VIS spectroscopy as well as cyclic voltammetry have been employed for characterizing the thin film chemical features, the band gap and the HOMO and LUMO levels. DFT computational studies were in close agreement with the experimental observables also showing intriguing geometrical effects on the band gap energy values. The comparison of the energy levels locations of the electrodeposited poly(naphthalenediimide-quaterthiophene) derivative (e-PNDIT4) and P3HT thin films transferred b…
Spatiotemporal colorimetry to reveal electrochemical kinetics of poly(o-toluidine) films along ITO surface
2018
Abstract Sheet resistance of transparent conducting electrodes can affect dramatically the electrochromic response of surface confined active species in any electrochromic device. The generated gradient of effective potential on the electrode surface has a direct impact on the electrochemical kinetics of these species. In this work, the electrochromic poly (o-toluidine) (POT) film, a derivative polyaniline, was deposited along a narrow, long transparent indium tin oxide (ITO) supporting electrode with a sheet resistivity of 30 Ω cm−1. This configuration was used as a model to simulate a surface electrical conduction from the external metallic contact to the opposite extreme of ITO with an i…
<title>Properties of ITO transparent electrode thin films on different substrates</title>
2003
Indium tin oxide (ITO) is optically transparent semiconductor that finds extensive applications in liquid crystal displays, photovoltaic cells, touch screen displays, electrochromic smart windows and more. As with all such electrode materials, there is a compromise between conductivity and optical properties. Different substrate materials and underlying layers are playing important role in transparency (better contrast and less absorption, increased brightness), surface morphology (smoothness, homogeneously) and conductivity of the ITO films. We compared optical, electrical and morphology properties of ITO films onto polymer substrate, obtained from company "SIDRABE Inc." (Latvia) and ITO f…
Digital video-electrochemistry (DVEC) to assess electrochromic materials in the frequency domain: RGB colorimetry impedance spectroscopy
2021
Abstract This work is the first one allowing the characterization of electrochromic devices simultaneously at various parts on their surface and different rates of color change. We describe a new proficient and affordable methodology for reporting electrochromic parameters such as coloration efficiency, optical contrast, and switching time based on the use of digital video-electrochemistry (DVEC) in the ac regime, namely RGB colorimetry impedance spectroscopy. Simultaneously with the electrochemical impedance spectroscopy, the RGB color changes of an electrochromic electrode were recorded by a CCD digital camera at 120 digital images per second. In such conditions, RGB electrochromic change…
<title>Long-term testing results of WO<formula><inf><roman>3</roman></inf></formula>-based electrochromic c…
1997
Two batches of the samples of electrochromic cell with WO3 and IrOx electrodes and Sb2O5 (DOT) water based solid electrolyte were tested at constant contrast ratio up to 107 cycles or stored during five years and the changes of current-voltage characteristics were studied. Two kinds of the changes were observed. The shift of curves along the voltage axis is supposed to be associated with the changes in the oxidation degree of tungsten oxide, while the changes in their shapes are associated with changes of water content in pores. The processes in the samples during cycling and storing are discussed.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the…
<title>Influence of treatment on stability of electrochromic WO<formula><inf><roman>3</roman></inf></formula&g…
1997
The influence of exposure in vacuum of 10-2 - 10-3 Pa and temperature treatment at 720 - 730 K in water vapor atmosphere on stability of tungsten oxide films in 0.1 N H2SO4 electrolyte were studied. The processes that take place during the film exposure in vacuum, determine the reduction of charge injection at the constant voltage change condition. In the case of temperature treatment the opposite changes of charge injection were observed. This indicates to opposite processes in films during both expositions. According to exposures characters, they could be a reduction of tungsten oxide initiated by oxygen evacuation from film in vacuum and film oxidation in water vapor media at high temper…
Chemical and electrochemical behaviour of 4,4’,4’’,4’’’-tetrakis(dimethylamino)-tetraphenylethylene in an oxidant environment: Toward a new sensor fo…
2020
Abstract Electrochromic compounds are suitable candidates for being used in sensor design. Here we report the use of 4,4’,4’’,4’’’-tetrakis(dimethylamino)-tetraphenylethylene for detecting both NO2 and SO2. Whereas the sensing mechanism in the case of nitrogen dioxide is a simple chemical oxidation reaction, in the case of sulfur dioxide, the mechanism is much more complex and the reaction requires the presence of t-butylhydroperoxide to take place. By modifying the detection conditions both compounds can be detected in gas phase. Additionally, a wide electrochemical study has been carried out to understand the role played by the t-butylhydroperoxide in the reaction with sulfur dioxide.
Validation of the mass response of a quartz crystal microbalance coated with Prussian Blue film for ac electrogravimetry
2000
Prussian Blue (PB) films have been considerably studied for many research applications such as electrochromic material development, new material for batteries, etc. Many analytical techniques were employed for examining PB electrochemical behaviour in solution and the quartz crystal microbalance (QCM) used in the alternative regime (ac electrogravimetry) appeared as an attractive in situ mass sensor due to its low cost and its high mass sensitivity. Unfortunately, the validity of the common Sauerbrey equation was questionable with these films or in other terms if the QCM was used as a pure mass sensor. In this work PB film is examined through acoustic measurements and the response can be in…
Innovative Combination of Three Alternating Current Relaxation Techniques: Electrical Charge, Mass, and Color Impedance Spectroscopy. Part II: Prussi…
2009
The simultaneous recording of three impedance functions (electrochemical impedance, color, and mass impedance) allows the role of different species to be distinguished easily during electrochemical processes in conducting and electrochromic films. Herein, this technique has been applied to the study of the Prussian blue films at several potentials between the blue form (Prussian blue) and the colorless form (Everitt’s salt). At these potentials, these electrochemical reactions take place by means of exchange of different ions. Thus, the exchange of potassium cations is related to the changes of absorbance at 690 nm, whereas the exchange of protons does not introduce color changes at this wa…