Diarylamino-substituted perylene compound: synthesis, fluorescence, and application in yellow LEDs

The fluorescent molecule N,N-bis(3',5'–bis(trifluoromethyl)-[1,1'–biphenyl]-4–yl)perylen-3-amine (TFPA) was designed and synthesized by introducing the strong electron-withdrawing trifluoromethyl group and the strong electron-donating diphenylamino group, with perylene as the core. The structure of the target product was identified by nuclear magnetic resonance, and its UV–vis absorption properties, fluorescence emission properties, quantum yield and lifetime were studied systematically. The results showed that the HOMO of TFPA was mainly localized in the perylene part with a small part localized in the triphenylamine structure. The LUMO was almost localized in the perylene part. Therefore, the ground-state absorption of TFPA is mainly attributed to the π–π* transition accompanied by with little the slight intramolecular charge transfer effect. The maximum emission peak (534 nm) of TFPA in the solid state was 18 nm redshifted compared to that of TFPA in solution (516 nm). TG results show that TFPA still does not decompose at 300 ℃, indicating good thermal stability. In addition, a yellow-light-emitting diode device based on the fluorescent molecule TFPA was constructed (CIE coordinates: 0.45, 0.54). The LED device showed good color purity (color purity: 97.8%). The results showed that TFPA was a luminescent material with excellent thermal stability and high color purity and had potential for use in fabricating yellow LEDs.