High-contrast electrochromic and electrofluorescent dual-switching materials based on 2-diphenylamine-(9,9-diphenylfluorene)-functionalized semi-aromatic polymers

Abstract

Two kinds of electrochromic and photoluminescence-active semi-aromatic polyamide and polyimide were prepared via condensation polymerization from a novel diamine, N,N-di-(4-aminophenyl)-2-amino-9,9-diphenylfluorene, with cycloaliphatic dicarboxylic acid and dianhydride, respectively. These polymers showed excellent solubility and increased thermal stability with 10% weight loss in excess of 450 °C in a N₂ atmosphere. Due to the stable electrochemistry and improved solid-state fluorescence properties, the polymer films exhibited repeatable and high-contrast electroswitching in both coloration and emission (ΔT% = 80–85%, I_off/I_on = 152.1–177.9). Especially, the polyamide still showed excellent electroswitching stability even after hundreds of cycles.