TAILORING ELECTROCHROMIC PROPERTIES USING POLY(N-VINYLCARBAZOLE) AND L-2-(2'-THIENYL)-5-(5''-VINYL-2''-THIENYL)PYRROLE) BLENDS

Blends of l-2-(2'-thienyl)-5-(5''-vinyl-2''-thienyl)pyrrole) (PSNPhS) and poly(N-vinylcarbazole) (PVK) were prepared in mass ratios of 1:4, 3:2, and 4:1. Their electrochromic properties were characterized using cyclic voltammetry, in situ spectroelectrochemistry, and spectrocolor imetry. Solid-state electrochromic devices were prepared using ITO/Myl ar substrates and a solid polymer electrolyte, with cast films of the polymer blends deposited on the working electrode. The color contrasts of these devices were measured by spectrocolorimetry conforming to th e Commission International de l'Eclairage (CIE) methods. The observed color changes in the p-doped state of the devices were compared using the CIE color coordinate values and correlate (R-2 = 0.97) With the qu antity of PSNPhS present in the blend, These combinations of PSNPhS an d PVK yielded colors similar to those of natural vegetation and soils, as desired.