Prussian Blue-Viologen Inorganic-Organic Hybrid Blend for Improved Electrochromic Performance

Electrochromic performance of an inorganic-organic layered blend consisting of prussian blue and ethyl viologen has been studied in the form of a device designed to test its performance as well as identify the working mechanism. Initially the sky-blue colored device, consisting of prussian blue and ethyl viologen electrodes, switches reversibly between transparent and dark blue states on application of electrical bias of up to 1.5 V with appropriate polarity. Raman spectroscopic and electrochemical investigations along with control experiments very clearly suggest that reversible redox switching of the two species are responsible for the electrochromism in the device. The fabricated device shows a good optical modulation of more than 50% in dual wavelength region of 400 and 600 nm (blue and red), serving as dual wavelength filter, while maintaining its optical durability for more than 8400 s (1400 pulses) with high coloration efficiency. The inorganic-organic hybrid device comprised of prussian blue and ethyl viologen as its active materials evinces a better class of electrochromic performance apropos to individual electrochromic material.