Vertical electrochromic display

Abstract

A directly addressable display device comprising at least one pixel cell (-), each pixel cell (-) being arranged for displaying a symbol, which symbol is repeatedly switchable between an on-state and an off-state, wherein each pixel cell (-) comprises an electrochromic layer () comprising an electrochromic and electrochemically active organic polymer material being electrochemically switchable between two different visually detectable coloring states; a counter electrode layer () comprising an electronically conductive material, wherein said counter electrode layer () in the viewing direction of the display device is arranged behind said electrochromic layer (); an electrolyte layer (), which electrolyte layer () is solid and arranged spatially between, and in ionic contact with, said electrochromic layer () and said counter electrode layer (); a symbol defining layer () which is electronically and ionically insulating, arranged in direct ionic contact with said electrochromic layer (), and which comprises one or more openings (-) which encloses said electrolyte layer () and defines the shape of said symbols; wherein said electrolyte layer () comprises a composition comprising a polyelectrolyte selected from one or more cationic polymers, wherein the electrolyte is substantially free of small cations.