Spray-processable red-to-transmissive electrochromic polymers towards fast switching time for display applications

Abstract

Novel spray-processable red-to-transmissive electrochromic polymers poly[3,4-di(2-ethylhexyloxy)thiophene-co-thiophene-co-3,4-di(methoxy)thiophene] with different monomer ratios have been synthesized and the electrochromic properties such as optical contrast, switching speed and long term switching stability were characterized. The incorporation of the simple thiophene unit into the polymer with the monomer ratio DEHOT : Th : DMOT = 1 : 0.2 : 0.8 successfully improves the switching speed (t₉₅ = 1.6 s) with a high optical contrast ΔT_max = 56% at 518 nm, which constitutes a forward step toward the dynamic electrochromic displays.