Poly films electrochromic performance

Poly(67), which is a low-gap material, has been used for the construction of a display in which the polymer acts as both anode and cathode [332]. Electrochromic devices using solid electrolytes have been prepared. One of them consists of poly(3-octylthiophene) or PP films with vanadium oxide as the counterelectrode and poly(ethyleneoxide) as the solid electrolyte [333]. However, the performances of these devices is low, reaching a maximum of 100-cycle operation, due to the instability of the polymers and the high operating temperatures. Much better results have been obtained with poly(EDOT). An electrochromic device based on this material and poly(ethylene oxide)-poly(phosphazene) as the solid electrolyte has been proposed [334] it may operate up to 1000 cycles without losses. 

Electrochromic devices using solid electrolytes have been produced more recently. A device [425] is based on poly(3-octylthiophene) or polypyrrole films with vanadium oxide as a counter-material and poly(ethylen-oxide) as a solid electrolyte. The poor performances (maximum 100 cycles of operation) of these early devices, due to the instability of the materials and the high operating temperature, have been greatly improved by the use of poly(3,4-ethylenedioxythiophene), provided with a low oxidation potential and optimum contrast, and of a poly(ethylenoxide)-poly(phospha-zene) solid electrolyte of high room temperature conductivity [153]. This device may be operated up to 1000 cycles without losses. 

In order to test this possibility, we built an electrochromic window based on Prussian blue (PB) and poly(3-4-ethylenedioxy thiophene (PEDOT) as electrochromic layers and we coated one of the electrode surface with a thin film of Ion Jelly based on [bmimJDCA (figure 4). This electrochromic window built performed reasonably well in what concerns contrast and stability (figure 5). Nevertheless further optimization of this concept should be performed in order to improve the switching velocity. (Vidinha et al., 2008)... 

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