Study on the Complementary Electrochromic Systems

• Main Authors: Shung-Jen Yu, 余尚仁
• Other Authors: Kuo-Chuan Ho
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/93490950498689625485

碩士 === 國立成功大學 === 化學工程研究所 === 83 === A solid-state electrochromic system is presented.　It is transparent and comprised of a tungsten oxide and Prussian blue (PB) thin film or its analog couple in combination with a proton- conducting, solid-polymer electrolyte.　Tungsten oxide thin films have been electrodeposited on TO glass.　PB thin films have been deposited by electrodeposition-galvanostatic (ED-G) method.　The transparent electrolyte is poly(2- acrylamido-2-methylpropane sulfonic acid), or Poly-AMPS, which was prepared by UV polymeriz- ation. The tungsten oxide thin films, which were prepared potentiostatically between －0.35 ∼ －0.45V vs. Ag/AgCl and maintained charge density below 600 mC/cm2 show have enough stability after 1,000 cycles. The transmittance difference measured at wavelength of 550 nm was greater than 75％. The show increasing absorption capability by higher potentials, the films suffered degradation due to hydrogen evolution. When potential is more negative than －0.4V(vs. Ag/AgCl). The WO3/ Poly-AMPS/PB devices were operated at low applied voltages, ＋1.2V to darken and －0.6V to bleach. The response time was 20s for bleaching, and 17s for darkening when the devices size was 5cm × 5cm. The coloration efficiency of the device is measured to be 53.9 cm2/C at 550nm.　 Two factors mainly responsible for the lack of electrochemical stability for the complementary device of WO3/Poly-AMPS/PB. Namely, the oxygen-containing polymer electrolyte and the charge imbalance between WO3 and PB electrodes. By substitating PB electrode with a PB analog, the indium hexacyanoferrate( InHCF),the device WO3/Poly-AMPS/InHCF apparently accomplishes higher cycling stability. This is because there is no need to precharge WO3 and thus preventing charge loss from the WO3 electrode.