Infrared spectral enhancement of an electrochromic cell by water removal

The spectroscopic properties of an electrochromic cell in the mid-infrared and near-infrared regions have been investigated. Absorption modes due to moisture were found to hinder the performance of the device by absorbing in the frequency range 3000 cm to 4000 cm. A method was developed to remove water from the cell by paying careful attention to the creation of the electrolyte gel. This electrolyte gel creation process was completed in an argon environment with low moisture content. The experimenters have had great success controlling the mid-infrared region of the cell by removing water from the electrolyte gel and preventing cell contact with air. The opaque state of our device showed 20% to 25% reflectance at 0 V applied potential over a range of 2000 cm to 6000 cm. At –1 V the device was maximally reflective at R=90% from 2000 cm to 6000 cm with a C-H absorption mode lowering reflectance to 65% at 3000 cm. The methods and devices used to create and protect a poly[3,4-(2,2-dimethylpropylene-dioxy)thiophene] (PProDOT-Me2) based electrochromic cell are presented.