Abstract
An Electrochromic window (ECW) is a strong candidate for an optical shutter. An ECW is composed of the conductive polymer as a working electrode and V2O5 as a counter electrode. The ECW technology switches between colored and bleached stages. In this paper the modification of a V2O5 thin film as a counter electrode is studied to increase contrast ratio of ECWs by adding TiO2 into V2O5. The dependence of the intercalation properties and transmissivity of V2O5-TiO2 composite films on various chemical compositions, a preparation and characterization of the films for use as a transparent ion storage layer in organic ECWs are focused on in this paper. A V2O5-TiO2 composite film was synthesized with sol-gel electrophoresis deposition method. Indium Tin Oxide (ITO) coated glass was used as an electrically conductive and transparent substrate. A V2O5-TiO2 composite film with V/Ti ratio of 70/30 in the reduced state showed 6 to 13improvement of transmissivity between 380 nm and 800 nm wavelengths as compared to a V2O5 thin film in the same state. Li+ intercalation rate was also observed to be higher. The composite film exhibited twice of capacitance than that of the V2O5 film. An ECW with the composite film exhibited 6higher contrast ratio than that with the V2O5 film. The contrast ratio of the ECW, measured as Δ%T, was equal to 56%, and ranged from 2to 58between the colored and bleached state measured at 580 nm wavelength. The color change response speed was also faster, i.e., only two seconds between fully colored and bleached stages.
Similar content being viewed by others
References
C Xu, L Lui, S Legenski, M Le Guilly, M Taya, A Weidner, “Enhanced Smart Window Based on Electrochromic (EC) Polymers.” Smart Structures and Materials, Proc. SPIE 5051, 404–411 (2003)
C.M. Lambert, Sol. Energy Mater. Sol. Cells. 76, 489–499 (2003).
W. Chen, Y. kaneko, N. Kinomura, “Preparation and Electrochromic Properties of V-Nb mixed-Oxide Films by Evaporation.” Journal of Applied Electrochemistry, 33, 515 (2003).
Kyoungho Lee, Guozhong Cao, “Enhancement of Intercalation Properties of V2O5 Film by TiO2 Addition.” J. Phys. Chem. B, 109, 11880–11885 (2005).
C. J Fontenot, J. W Wiench, M Pruski, G. L Schrader, J. Phys. Chem. B, 104, 11622 (2000).
J Steven, Seana Limmer, Yun Wu, Tammy P. Chou, Carolyn Nguyen, Guozhong Cao, Adv. Funct. Mater. 12, 59–64 (2002).
Chunye Xu, Lu Liu, Susan E. Legenski, Dai Ning, Minoru Taya, Journal of Materials Research, 19 (7), 2072–2080 (2004).
Shawn A. Sapp, Gregory A. Sotzing, John R. Reynads, Chem. Mater. 10, 2101–2108 (1998).
C. G. Granqrist, Handbook of Inorganic Electrochromic Materials, (Elsevier, 1995) pp. 265–275.
Dai Ning, Chunye Xu, Lu Liu, Calen Kaneko, Minoru Taya, Proc. of SPIE, 5759, 260–267 (2005).
Calen Kaneko, Chunye Xu, Lu Liu, Dai Ning, Minoru Taya, Proc. of SPIE, 5759, 518–524 (2005).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kim, S., Xu, C. & Taya, M. Enhanced contrast ratio of an electrochromic window (ECW) based on a V2O5-TiO2 composite thin film as a counter electrode. MRS Online Proceedings Library 928, 1426 (2006). https://doi.org/10.1557/PROC-0928-GG14-26
Received:
Accepted:
Published:
DOI: https://doi.org/10.1557/PROC-0928-GG14-26