Microporous patterned electrodes for color-matched electrochromic polymer displays

The emergence of electroactive and conducting polymers offers new opportunities for the design of materials for electrochromic devices (ECDs). Of these, poly(3,4-alkylenedioxythiophene)s (PXDOTs) and their derivatives exhibit the most promising electrochromic (EC) properties. Here, we report the use of highly porous metallized membranes which allow the production of patterned, rapid-switching, reflective ECDs. Using poly(3,4-ethylenedioxithiophene) (PEDOT), poly(3.,4-propylenedioxythiophene) (PProDOT), and the dimethyl-substituted derivative PProDOT-Me-2 as the active EC materials, we have obtained switching times of 0.1-0.2 s (5-10 Hz) to achieve full EC contrast. These polymers yield reflective contrast values of up to 90% in the NIR and similar to60% in the visible regions. In addition, the ECDs were switched repetitively, 180 000 times with less than 10% contrast loss. We have also demonstrated a 2 x 2 pixelated display device built using shadow mask patterning. Two cathodically coloring polymers which exhibit two distinct colors in their neutral states (blue and red) are patterned on a porous metallized electrode to yield a highly contrasted surface. Upon simultaneous oxidation of these polymers, the bi-color surface is rapidly bleached presenting a uniform shiny gold surface.