In-situ spectroscopic studies of viologen based electrochromic device

摘要

Fabrication and operation of simple solid state electrochromic devices usingethyl viologen diperchlorate in a polymer matrix is presented here. In-situRaman and transmission/absorption studies have been done to establish theorigin of bias induced color change, between a transparent and navy blue color,in the electrochromic device. The origin of bias induced color change has beenattributed to the bias induced redox switching between its viologen dicationand free redicle forms. Fundamental reason behind colour changes of viologenmolecule has been established. In-situ UV-Vis spectra reveals that the navyblue color of the device under biased condition is not due to increase in thetransparency corresponding to blue wavelength but due to suppression of thetransparency corresponding to the complementary colors. Absorption modulationhas been reported from the device with good ON/OFF contrast of the device.