| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 93 === In this thesis, two conducting polymers, polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT) were used to construct a complementary electrochromic device (ECD), in which PANI served as the anodically coloring material and PEDOT as the cathodically coloring one. After knowing the electrochemical and optical properties of these two materials, the effect of the coloring and bleaching voltages on the optical attenuation performance and the cycling stability of the ECD were discussed. Moreover, the design equations for the ECD with different charge capacity ratios (CCRs), and the use of ionic liquid as an electrolyte were also discussed.
For PANI thin film, the operating potential window was controlled between -0.5 and 0 V. From the spectral analysis, the adding of proton into electrolyte enhanced the cycling stability. By the analysis of the coloration efficiency, PANI thin film has three values of the coloration efficiency. In the chosen operating potential (-0.5~0 V), the coloration efficiency was calculated to be 25 cm2/C. From the EQCM analysis, not only ClO4- dominated the neutrality of PANI but anion also played an important role. For PEDOT thin film, the operating potential window was controlled between 0.3 and -1.0 V and the coloration efficiency was calculated to be 206 cm2/C, so that it dominated the color change of the ECD. From the EQCM analysis, the mass of PEDOT thin film increased with cycling numbers. This may due to the porous morphology that the solvent (propylene carbonate) would accompany with cations being inserted into the PEDOT film or anions (H+ and Li+) with larger mobility being incorporated into the film first and then blocked the expulsion of anions.
The bleached and colored state transmittances at 570 nm of the PANI-PEDOT ECD were 58~62% at -0.6 V and 15~20% at 1.0 V, respectively, with delta T of about 40~45%. After 11,400 cycles, delta T of the ECD was 41.6%, which was 96% of its initial value; after 23,200 cycles, delta T of the ECD was 33.8%, and was 78% of the initial value. The response times for the coloring and bleaching processes were 1.1 s and 0.4 s, respectively. The coloration efficiency of the ECD was 285 cm2/C at 570 nm and this value was quite close to the sum of the coloration efficiency of each EC material. The optical attenuation performances of ECDs with different CCRs were also measured. The consumed charges of the ECDs were found to be equal to the charge capacity of PEDOT and the experimental data were fitted well by the design equations. By choosing ionic liquid as an electrolyte, ΔT remained 85% of the initial
value after 2 x 104 cycles. This shows that electrolyte is an important
issue for the cycling stability.
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