Topic
Electrochromism
About: Electrochromism is a research topic. Over the lifetime, 13097 publications have been published within this topic receiving 294637 citations.
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TL;DR: In this paper, a colorimetric method for the in situ study of electrochromic polymers based on the CIE system of colorimetry is reported. But the method is only applicable to dual polymers.
Abstract: We report a colorimetric method for the in situ study of electrochromic polymers based on the CIE system of colorimetry. This method is useful for the comparison of the electrochemical and optical properties of conjugated polymers, and for gaining control of the color of dual polymer electrochromic devices. Twelve electrochromic polymers were investigated using in situ colorimetric analysis in order to define their CIE coordinates and electrochemical potential windows. By controlling the electron density and steric interactions along conjugated polymer backbones, we have developed a set of electrochromic polymers that provides colors throughout the full range of color space. The applicability of the method is illustrated with a model dual polymer device based on poly(2-(3,4-ethylenedioxy)thienyl(biphenyl)) (PBEDOT-BP) and poly(3,6-bis(3,4-ethylenedioxy)thienyl)-N-methylcarbazole) (PBEDOT-NMeCz). This device yields green/brown colors (L* = 48, a* = 0, b* = 20 and L* = 44, a* = 6, b* = 26) interesting for e...
240 citations
TL;DR: In this article, the authors provide an up-to-date review of more than a century of research on the growth of vanadium oxide thin films and the Bohr radius for V2O5 gels.
239 citations
TL;DR: Anodically electrodeposited iridium oxide films from alkaline solutions were investigated for application to electrochromic devices as discussed by the authors, which showed good reaction reversibility and coloration efficiency.
Abstract: Anodically electrodeposited iridium oxide films from alkaline solutions were investigated for application to electrochromic devices Micro-crystalline (diameter: 15A) films obtained by the electrolysis of aqueous alkaline solutions containing iridium chloride, oxalic acid and potassium carbonate showed good electrochromic reaction reversibility The coloration efficiency of the films was about one third that of typical evaporated tungsten oxide films, and the response rate measured by the amount of injected charge was about double The cycle lives of the cells, composed of electrodeposited films, 1M H3PO4-NaOH (pH=3~5), and an activated carbon cloth, were more than 8 × 106 with a 06 V, 1 Hz continuous square wave
237 citations
TL;DR: In this article, a brief updated review of sol-gel-derived electrochromic films of different chemical systems is presented, where performances of selected films measured in electrochemical cells or in devices are discussed and degradation problems experienced by different authors enumerated.
235 citations
TL;DR: In this paper, a review describes recent developments in the synthesis of viologen-based electrochromes with co-redox species and their ECD performance, which includes the incorporation of conducting polymers in the device set-up and/or the addition of complementary redox species.
Abstract: Considerable interest is raised by organic materials owing to their exceptional performance in electronic and optoelectronic applications. Among these, electrochromic materials (EC) that can be switched between a distinct color and a bleached state exhibiting high contrast, multicolor and improved long-term stability are attractive in the fabrication of electrochromic devices (ECDs). Ionic materials, in particular, have received persistent attention owing to their tunable optical and electronic properties. 4,4′-Bipyridinium salts, commonly called viologens (V2+), are a well-recognized class of electrochromic materials that exhibit three reversible redox states, namely, V2+ (dication, pale yellow colored/colorless) ↔ V+˙ (radical cation, violet/blue/green) ↔ V0 (neutral, colorless). The electrochromic properties of these materials can be modulated by varying the nitrogen substituents on the pyridyl ‘N’; also, besides this, varying the counter ions with specific functionalities has been shown to enhance the electrochromic behavior, such as switching time, cycling stability and device performance. Although ECDs based on viologens are well regarded for their low operational voltages, they exhibit certain disadvantages such as low cycle life and poor efficiency of the device in the long term. Extensive efforts have been made to fine tune the EC properties of viologens, either through alteration or by adding suitable electrochromic counter electrode materials, which includes the incorporation of conducting polymers in the device set-up and/or the addition of complementary redox species. Optimization of the device parameters has shown that the addition of such external agents has a positive effect on the overall device performance. This review describes recent developments in the synthesis of viologen-based electrochromes with co-redox species and their ECD performance.
235 citations