Pyrene-based blue emitters with aggregation-induced emission features for high-performance organic light-emitting diodes

Abstract

Pyrene is a representative aggregation-caused quenching (ACQ) chromophore. Herein, by introducing tetraphenylethylene or triphenylethylene with a typical aggregation-induced emission (AIE) characteristic at pyrene's 2,7-positions, we have succeeded in converting it into AIE luminogens (AIEgens). The new compounds, namely Py-TPE and Py-TriPE, exhibit strong sky-blue emission (<490 nm) with high quantum yields in both aggregated state and solid state. Non-doped organic light-emitting diodes (OLEDs) using Py-TPE and Py-TriPE as emitters are fabricated. Among them, the device with a configuration of ITO/HATCN (5 nm)/TAPC (40 nm)/TCTA (5 nm)/Py-TPE (20 nm)/Bepp2 (45 nm)/Liq (2 nm)/Al emits sky-blue light at 492 nm at a low turn-on voltage (3.1 V) with a maximum luminance of 15 750 cd m⁻², a current efficiency of 7.34 cd A⁻¹, a power efficiency of 6.40 lm W⁻¹ and an external quantum efficiency of 3.19%. The electron transporting and symmetry properties of the present AIEgens are found to play significant roles in improving the luminance of the devices with a low efficiency roll-off. This work thus opens up new avenues for the design of new pyrene-based AIEgens for fabricating blue high-performance OLEDs.