Wide band electrochromic displays based on thin conducting polymer films

New, wide band. flexible electrochromic displays have been realized with mi croporous membranes metallized with gold that acts both as an electrode and a reflecting layer. A control of the relative contribution of specular and diffuse reflectance to the optical response of displays can be achieved by Varying the size of pores in the membrane. The active layer is a thin cond ucting polymer layer electrochemically deposited on the metallized membrane . Polydiphenylamine and poly(3,4-ethylenedioxythiophene), which show good e lectrochemical and optical properties, were used as active layers. These de vices exhibit great contrast in the visible/near infrared (IR) spectral reg ion with high reflectance in their reflecting state. IR reflectance measure ments showed that swelling can induce reversible wide band contrast in mid- IR and far-IR. These results were correlated to morphological changes induc ed by ions movements in the polymer films by using EQCM measurements with f ast simultaneous acquisition of frequency and impedance. (C) 2001 Elsevier Science Ltd. All rights reserved.