Aggregation-Induced Emissions of Fluorenonearylamine Derivatives:  A New Kind of Materials for Nondoped Red Organic Light-Emitting Diodes

A new kind of fluorenonearylamine derivatives possessing vagarious red-emitting aggregation-induced emission (AIE) characteristics was reported for the first time. On the basis of theoretical calculations and experimental results, the AIE was found to originate from the unique dimer (excimer) specifically in the aggregates. In the crystals of both compounds, every two molecules are bond together by intermolecular O···H or C···C bonds to form particular dimers. In virtue of their nice solid-state red fluorescence, nondoped red-light OLEDs based on these AIE-active materials were fabricated. The devices exhibited low turn-on voltages of about 3 V, luminescence of 14135 and 4813 cd m-2, and efficiencies of 1.40 and 0.35 lm W-1 based on the two materials. The results demonstrated that such AIE-active materials are promising candidates for nondoped red emission OLED applications.