Novel electrofluorochromic materials based on asymmetric D-A-D′ type indolocarbazole-imidazole-triarylamine derivatives

Abstract Five indolocarbazole-imidazole-triphenylamine derivatives (5a-e) were designed and synthesized as novel D-A-D′ asymmetric type electrofluorochromic (EFC) materials. Their thermal properties, photophysical properties and electrochemical properties were studied. Five compounds could form uniform amorphous films due to good thermal stability. All compounds exhibited reversible redox-active and EFC characteristics, both the ultraviolet absorption (UV) spectra and the photoluminescence (PL) spectra changed with the change of voltage applied. Intramolecular charge transfer (ICT) characteristics made the compounds more sensitive response to voltage applied. Finally, the EFC devices of five compounds were successfully fabricated, the CV curves of 300 cycles were used to test the stability of the devices. Five devices displayed blue fluorescent switching characteristics and showed different electrochemical behaviors under different voltage applied. Among them, the device of the compound 5e with –OCH3 exhibited the most stable device performance. The asymmetric D-A-D′ type small molecules with the redox-active can provide the feasibility for realizing multifunctional EFC devices.