Absorption spectra electrochromic devices

The considerable changes in the optical absorption of CPs during the dopingundoping process are at the basis of many proposals for electrochromical devices, such as smart windows, whose light transmission can be electrically controlled, and various display devices. Due to the drastic change that appears in their visible spectrum, PTh [122-124] and PAni [125] are... 

The modification of the redox state of PEDOT will change its morphology [35, 64, 65] and absorption spectrum. Hence its absorption can be tuned electrochemlcally. PEDOT and other PEDOT-type polymers therefore exhibit electrochromic properties, which can be utilized in appropriate devices [62, 66, 67]. Conductivity will change simultaneously and may be used to switch the area between source and drain in a transistor-like structure [68]. 

The absorption spectrum of PEDOTrPSS strongly depends on the PEDOT oxidation state, and this has motivated many groups to investigate this material in electrochromic devices (see Chapter 10). 

By combining two electrochromic materials whose neutral states are transparent in file visible, with one electrode anodically colored while the other is cathodically colored, allows fabrication of a device that can switch between highly transmissive and absorptive states. These kinds of ECDs are used as smart windows. In the case of electrochromic materials where the neutral state shows absorption in the visible, it is possible to choose as the secondary electrode a material whose neutral state absmption is conqilementaiy to fiiat of the primary electrode, and its reduced form shows file same color as t of file oxidized form of file primary electrode. In other words, file combination of the spectra of two con lementary colors leads to absorption over the whole visible spectrum turning file device black. Upon potential switching between file two redox states, the electrochromic cell will turn from black to the characteristic color of the original forms. 

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