Electrochromic Properties of Sputtered Iridium Oxide Thin Films with Various Film Thicknesses

Abstract

Iridium oxide is an anodic electrochromic material, which takes on a blue-black color through electrochemical oxidation and turns to transparent via reduction. Hydrated amorphous Ir oxide thin films with various thicknesses from 20 to 400 nm were prepared by reactive sputtering in a H 2 O atmosphere, and their transmittance spectra in both the bleached and colored states as well as their response times were examined in this study. The bleached and colored transmittances decreased with increasing film thickness according to Lambert's law, and the absorption coefficients in the bleached and colored states were estimated to be 3. , respectively, at a wavelength of 600 nm. The results point to almost all the Ir atoms being electrochemically active and contributing to the color change. A maximum transmittance change of 81% was obtained for the 400 nm-thick film. Further, there was a trade-off between the response speed and the transmittance change. The response speed slowed down with increasing the film thickness, while the coloring and bleaching response time for the thick films was several tens of seconds.

Two-color electrochromic devices using a tungsten oxide and nickel oxide double layer

“…This result agrees with the previously reported data showing that the transmittance change increased with increasing thickness of the EC layers. [33][34][35] The data for the IWNI device with a doublelayer thickness of 200 nm were studied in more detail because the device showed higher performance.…”

Compensative Electrochromic Device Utilizing Electro-deposited Plasmonic Silver Nanoparticles and Manganese Oxide to Achieve Retention of Chromatic Color

“…[2][3][4] Various types of EC materials, including inorganic and organic materials, have been investigated. Transition metal oxides, [5][6][7][8][9][10] Prussian blue, [11][12][13] and Prussian blue analogs 14,15 are examples of inorganic EC materials. These inorganic EC materials have excellent stability and have already been utilized as smart windows.…”

The determination of electrolyte stability and conditions for electrochromic WO3 films deposition

“…The color change of these materials is a result of an electrochemical reaction. The initial state, which is usually transparent, changes to colored as a result of electrochemical reduction (the so-called cathodic materials) [3,4] or electrochemical oxidation (the so-called anodic materials) [5,6]. The tungsten trioxide is a well-known cathodic material [7].…”