AVS 53rd International Symposium
    Thin Film Thursday Sessions
       Session TF-ThP

Paper TF-ThP1
Electrochromic Smart Windows Based On Titanium Doped WO@sub 3@ Thin Films

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Thin Film Poster Session
Presenter: A. Karuppasamy, Indian Institute of Technology Madras, India
Authors: A. Karuppasamy, Indian Institute of Technology Madras, India
A. Subrahmanyam, Indian Institute of Technology Madras, India
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Smart windows are electrochromic glass window panes that can change their transparency value in response to an applied voltage pulse. In the present study, we have developed the proton based and lithium based monolithic electrochromic structures consisting of five thin film layers; Glass/ITO/Ti:WO@sub 3@/Ta@sub 2@O@sub 5@/NiO/ITO and Glass/ITO/Ti:WO@sub 3@/LiAlF@sub 4@/NiO/ITO respectively. The Ionic conductor (Ta@sub 2@O@sub 5@) and ion storage layer (NiO) were deposited by electron beam evaporation and the active electrochromic (EC) layer (Ti:WO@sub 3@) was deposited by reactive pulsed dc magnetron sputtering. Pure Titanium and Tungsten metal targets were co-sputtered in argon and oxygen atmospheres keeping the sputtering power constant. The smart window performance of the EC film was systematically studied in three steps. First, the material properties of the EC film were investigated by XRD, AFM, UV-Vis spectrophotometer and Kelvin probe. The thickness and the optical constants were estimated from the reflectance measurements. Secondly, the electrochromic behaviour of the EC film was characterized by cyclic voltammetry (CV). The CV measurements were performed using a potentiostat with a standard three-electrode configuration consisting of the sample as the working electrode.1.0 MLiClO@sub 4@ in PC and 1.0 MHCL were used as electrolytes. Finally, the smart window comprising of five layers were devoloped and tested. The optical modulation (@DELTA@OD), coloration effiiency(CE) and switching time(@tau@@sub s@) for the proton based device was found to be better with typical values; @DELTA@OD = 60%, CE = 80 cm@super 2@/C (at@lambda@=550nm) and @tau@@subs@~1s (for 1cm x 1cm device).