| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 88 === An all solid-state electrochromic device (ASSECD) is formed by anodically colored polyaniline (PAni) and cathodically colored tungsten trioxide (WO3), separated by a protonic solid polymer electrolyte, poly(2-acrylamido-2-methylpropane sulfonic acid), or PAMPS. This study is about the exploration of the electrochromic properties of the ECD, the influence of water content and oxygen in the electrolyte on the ECD. The stability of the ECD stored without applying voltage will also be discussed in this study.
The PAni and WO3 thin films used in this study were prepared by galvanostatic and potentiostatic electrodeposition methods, respectively. The optical properties of the PAni and WO3 thin films in solid PAMPS were studied with the aid of the hole-method and pseudo reference electrode Ag.
It was found that the coloration efficiency of the device is the sum of the coloration efficiency of PAni and that of WO3, which is consistent with the additive property of the complementary ECD. It was also concluded that the cycling stability of the ECD was influenced by the water content of the PAMPS. Good cycling stability can be obtained when n < 5 (n is the mole ratio of H2O to SO3-). In the memory-test experiment, it was noticed that oxygen would cause the self-bleaching of colored ECD, due to the oxidation on the WO3 electrode. The oxygen content, therefore, plays an important role in determining the memory stability of ECD. Thus, the transmittance window of the device during at-rest will tend to decrease as a result of charge decay. The difference in the loss of the charge capacity for the PAni and WO3 electrodes would hurt the performance of ECD. Charge balancing can be achieved by adding a third electrode, such as platinum wire, so as to improve the lifetime of the ECD.
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