An Electrochromic Device Having Absorption in the Entire Visible Range with Ruthenium-based Metallo-supramolecular Polymers and Polyaniline-Poly(4-styrenesulfonate) Composite Films

• Main Authors: Wan-Hsuan Chou, 周宛璇
• Other Authors: Kuo-Chuan Ho
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/67732236921243844550

碩士 === 國立臺灣大學 === 高分子科學與工程學研究所 === 102 === Only a few limited researches devoting to electrochromic devices (ECDs) having absorption in the entire visible range (or all-band absorption). Electrochromic materials with complementary colour have potential to be fabricated as ECDs having all-band absorption. Comparing with other complicated syntheses of black-to-transparent ECDs, this work provides a simple way to build up a black-to-transparent ECD. Metallo-supramolecular polymers (MEPEs) are metallic-organic complexes. In recent year, MEPEs have shown good performance in many electrochemical systems including eletrochrmism. Several transition metal ions, such as iron (Fe) and ruthenium (Ru), have been proposed as the source of material ions for MEPEs. In this work, optical, electrochemical properties of Ru-based MEPE are presented. Ru-based MEPE, having red colour, offers great redox reversibility and high transmittance change (ΔT=52% at 510 nm) because of the metal-to-ligand charge transfer (MLCT). From EQCM analysis, the molar flux of the anion and solvent could be calculated through the charge and mass change of the thin film. On the other hand, polyaniline doped with polystyrene sulfonate (PANI:PSS) is water-dispersible and suitable to arrange in pairs with Ru-MEPE. These two thin-film materials are easily prepared and coated on ITO substrate by spray coating. The redox reaction for the complementary ECD consisting of Ru-MEPE/PANI:PSS can be driven between -1.5 V and 1.5 V. The ECD becomes black at -1.5 V (Ru-MEPE vs. PANI:PSS) while it is colourless at 1.5 V. The influence of the charge capacity ratio of the two electrodes on the transmittance change of the ECDs has been tried, and the best condition is found at a charge capacity of 0.75. Its largest transmittance change is about 40.1% at 510 nm, as compared to 28.6% and 32.3%, at 550 nm and 700 nm, respectively. The switching times (defined as the time it takes for reaching 95% saturated transmittance change at 510 nm) are 4.0 s for darkening and 1.3 s for bleaching. From the electrochemical analysis, we prepared stable ECD with only a small transmittance decay after 200 cycles at the specific wavelength.