Enhanced Durability of an All-Solid-State WO₃ Based Electrochromic Device on a Single Substrate by Using a Complementary Anodically Coloring Poly(o-ethoxyaniline)

Electrochromic (EC) devices represent one of the most promising energy-saving and solar control technologies for the market of energy-efficient building and optoelectronic devices by offering dynamic control of the optical transmission of visible and near-infrared light. Although notable results are achieved in terms of material and EC performance, a continuous and intense effort is currently devoted to the development of effective solid-state systems capable of providing excellent durability. Here, poly(o-ethoxyaniline) (POEA), a derivative of PANI capable of being more easily processed by solution deposition techniques than PANI, is used as both anodic EC and protective layer to fabricate a complementary all-solid-state WO3/POEA based EC device on a single-glass substrate. The introduction of POEA, synthesized by chemical oxidative polymerization, enabled a more marked protection against the degradative processes occurring at the anode side, promoting at the same time a more effective conversion between the different WO3 redox states, fast switching dynamics, and a high coloration efficiency (eta = 150 cm(2) C- 1). Besides determining a significant gain in EC performance, POEA permits us to maintain a good optical response and electrochemical stability after 1000 CV cycles, conferring an enhanced durability with respect to similar monolithic all-solid-state WO3 based EC devices.