Polymer‐Based Solid Electrochromic Cell for Matrix‐Addressable Display Devices

Abstract

Electrochromic display devices (ECD) based on polymer electrolytes are of growing importance in view of their specific properties compared to liquid devices. One of them, which is very interesting from a practical point of view, is the possibility of obtaining a strong dependence of the response time of the display on the temperature. This particular property may be conveniently used to obtain matrix‐addressable displays. The electrochromic characteristics of electrolyte/stainless steel display devices have been investigated using cyclic voltammetry and chronoamperometry coupled with optical reflection measurements. The polymers used in this study are , , and . The thermal sensitivity of these displays is mainly due to the change of the electrolyte conductivity vs. temperature. For PEO‐based electrolyte, this variation is related to a transition between a crystalline and an “amorphous” or liquid state, at 50–70°C. On the other hand, PPO and PVP based electrolytes are amorphous in the temperature range investigated. PVP based electrolytes presents a glass transition temperature around 50–60°C. These studies show that better performances of ECD are obtained with lithium electrolytes in comparison to protonic electrolytes. This point will be discussed in this paper.