Development of Electrochromic Device with Poly(3,4-ethylenedioxythiophene) on Invisible Silver-Grid Transparent Electrode

Abstract

Electrochromic (EC) reaction is defined as a reversible color change which induced by the electrochemical redox reactions. The EC device is promising as an optical modulation device such as a display and a window. However, a flexibilities of the EC device is unsatisfied because conventional EC device consists of transparent conductive oxide on the glass substrate. To overcome this, we have developed a gravure offset printed invisible Ag-grid transparent electrodes by using Ag-nanoparticles ink,[1] and demonstrated that a powder electroluminescent device by this transparent electrode showed the high bending stability.[2], [3] Therefore, it is also expected the realization of EC device showing high bending durability.In this study, the novel EC device composed of poly(3,4-ethyenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) has been fabricated on a gravure offset printed fine Ag-grid transparent electrode and evaluated optical and electrochemical properties. Scanning the potential from 0 V (vs. Ag/Ag+) to the negative direction, the cathodic current due to the reductive reaction of PEDOT:PSS was observed, and the absorbance correspond to the coloration of PEDOT:PSS was increased. Then, when scanning the potential to the positive direction, the anodic current due to the oxidative reaction of PEDOT:PSS was observed, and the absorbance was decreased. This changing in the absorbance were observed several tens of times. These evaluation results demonstrate that PEDOT:PSS develops a reversible color change with the EC reaction on the fine silver-grid transparent electrode. Reference [1] M. Ohsawa, N. Hashimoto, Mater. Res. Express, 5, 085030 (2018).[2] N. Takeda, S. Tsuneyasu, K. Yanagawa, N. Hashimoto, M. Ohsawa, T. Satoh, Electron. Lett., in press.[3] M. Ohsawa, N. Hashimoto, N. Takeda, S. Tsuneyasu, T. Satoh, Flex. Print. Electron. (under review). Figure 1