Microporous patterned electrodes for color-matched electrochromic polymer displays

2004-06-15
Aubert, Pierre-Henri
ARGUN, Avni A.
Çırpan, Ali
TANNER, David B.
REYNOLDS, John R.
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.