| Summary: | 碩士 === 淡江大學 === 化學工程與材料工程學系碩士班 === 102 === In this study, flexible complementary electrochromic devices (ECD) constructed using polyaniline (Pani) and tungsten trioxide (WO3) thin films with succinonitrile/polyethylene glycol (SN/PEG) composite solid-state electrolyte are fabricated and characterized. Pani and WO3 thin films are prepared by potentiostatic electrodeposition on indium tin oxide (ITO) conducting glass (at part 1 and part 2) or indium tin oxide-polyethylene naphthalate (ITO-PEN) conducting plastic (part 3) as the electrochromic layers. At part 1, liquid electrolyte contain 0.1 M LiClO4 and 1 mM HClO4 in propylene carbonate (PC) solution are prepared and are used to fabricate the ECD. The area of the ECD is 2 × 2 cm2. ECD constructed using stationarty deposition time of Pani thin film and different deposition time of WO3 thin film, then find the best deposition time ratio according to transmittance modulation ability (ΔT) and current density. Using the new method to find the best operation potential range of ECD. Composite solid-state electrolytes contain 0.1 M LiClO4 and 1 mM HClO4 with different SN/PEG ratios (from 95/5 to 65/35 (w/w)) are prepared and are used to fabricate the ECDs. The electrochromic performances of the ECDs using a liquid electrolyte (l-ECD) with ITO or solid-state electrolyte with ITO (s-ECD) or solid-state electrolyte with ITO-PEN (fs-ECD) are investigated and compared. Ion diffusion rate of liquid electrolyte and solid-state electrolyte are investigated by electrochemical impedance spectroscopy (EIS).
Experimental results reveal that the deposition time ratio of Pani thin film and WO3 thin film as 100s：1200s have larger ΔT and current density than other ratio. The best operation potential of the ECD is determined to be 1.0 V for coloring and -0.3 V for bleaching process. Solid-state electrolyte of SN/PEG ratio (90/10) can be effectively inhibit crystallization of SN. l-ECD achieved ΔT of 56.66 % at 700 nm. The ΔT% of s-ECD at SN/PEG ratio of 90/10 is 51.25 % at 700 nm. The ΔT of fs-ECD at SN/PEG ratio of 90/10 is 50.76 % at 700 nm. The coloring/bleaching response times are 20.3 s/9.1 s for l-ECD and are 28.4 s/14.4 s for s-ECD (SN/PEG = 90/10), and fs-ECD (SN/PEG = 90/10) are 26.6 s/16.3 s.The coloration efficiency of l-ECD、s-ECD (SN/PEG = 90/10) and fs-ECD (SN/PEG = 90/10) are 97.0、105.0 and 100.4 cm2/C, respectively. The l-ECD after switching for 1300 cycles, ΔT% decline of 10% compared to the initial ΔT%. The s-ECD (SN/PEG = 90/10) after switching for 4600 cycles, ΔT% decline of 10% compared to the initial ΔT%. The fs-ECD (SN/PEG = 90/10) after switching for 4400 cycles, ΔT% decline of 10% compared to the initial ΔT%. The l-ECD less stable than s-ECD and fs-ECD because liquid electrolyte prone to leak.
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