2004 Volume 72 Issue 5 Pages 304-309
An aramid resin, poly(p-phenylene terephtalamide) (PPTA) was available on an ITO electrode as a stable matrix film. Electrochromic iridium oxide was electrodeposited on the electrode. In the oxidized state, original iridium oxide without PPTA film showed blue, while the PPTA / iridium oxide film showed greenish blue: the maximum absorption wavelength of the original iridium oxide film was about 650 nm, while that of the PPTA / iridium oxide film was about 600 nm. The XPS-biding energy of Ir 4f5/2 and Ir 4f7/2 electrons was shifted to about 2 eV higher energy, meaning that the color change was probably due to donating of the lone pair electrons of PPTA to the indium. The electrodeposition of Au on the PPTA / iridium oxide film was carried out. The obtained Au-electrodeposited PPTA / iridium oxide film showed quite different electrochromic properties. New redox current peaks appeared in the CV of the film. The film was colored vermilion in the reduced state and greenish blue in the oxidized state. The XPS-biding energy of Ir 4f5/2 and Ir 4f7/2 electrons was shifted to about 2 eV lower energy, implying that the electrodeposition of Au transformed the electronic state and structure of iridium oxide, suggesting the formation of a -Au-CI-Ir- binuclear Cl-bridged complex and/or the plasmon absorption of the Au microparticles dispersed in the PPTA film.
