Yellow electrochromic polymer materials with fine tuning electrofluorescences by adjusting steric hindrance of side chains

Abstract

A series of novel conducting conjugated yellow-to-transmissive electrochromic (EC) polymers were designed and synthesized to research their structure–property relationships, achieving electrofluorescent (EF) switching with applied external potential. These bifunctional materials are based on repeat units of bi-phenyl-1,3,4-oxadiazole and thiophene derivatives with different side chains. The polymers present a similar yellow color and emit various fluorescences with applied reduction potential, and they can turn to nearly transparent and non-fluorescent with oxidization potential. The optical contrast, electrochemical, electrochromic and electrofluorescent switching properties were also characterized in detail. A device containing these polymers was also fabricated that can achieve electrochromic and electrofluorescent switching simultaneously, making these polymers promising candidates for electro-bifunctional materials.