Pyrene-Based Blue AIEgen: Enhanced Hole Mobility and Good EL Performance in Solution-Processed OLEDs

Abstract

Organic luminogens with strong solid-state emission have attracted much attention for their widely practical applications. However, the traditional organic luminogens with planar conformations often suffer from the notorious aggregation-caused quenching (ACQ) effect in solid state for the π–π stacking. Here, a highly efficient blue emitter TPE-4Py with an aggregation-induced emission (AIE) effect is achieved by combining twisted tetraphenylethene (TPE) core and planar pyrene peripheries. When the emitter was spin-coated in non-doped OLEDs with or without a hole-transporting layer, comparable EL performance was achieved, showing the bifunctional property as both an emitter and a hole-transporting layer. Furthermore, its EL efficiency was promoted in doped OLED, even at a high doping concentration (50%), because of its novel AIE effect, with a current efficiency up to 4.9 cd/A at 484 nm.

Pyrene-based aggregation-induced emission luminogens and their applications

“…48 Furthermore, Yanget et al reported the highly efficient blue emitter TPE-4Py 26 with an AIE effect, which is achieved by a combination of a twisted tetraphenylethene (TPE) core and planar pyrenes on the periphery. 49 Its EL efficiency was enhanced in doped OLEDs, at high doping concentration (50%), with a current efficiency up to 4.9 cd A À1 at 484 nm (Fig. 17).…”

3,3′-Bicarbazole-Based Host Molecules for Solution-Processed Phosphorescent OLEDs

“…Because the n-butyl group in BCz-nBuPh exhibited less steric hindrance than the t-butyl group in BCz-tBuPh , molecules of BCz-nBuPh within the film exhibited a strong degree of molecular aggregation. t-Butyl groups have been introduced to blue emitting molecules to prevent molecular quenching [ 21 , 22 ]. BCz-tBuPh with t-butyl groups was expected to yield better host materials than BCz-nBuPh with regard to thermal and optical properties.…”

Aggregation-Induced Emission Properties in Fully π-Conjugated Polymers, Dendrimers, and Oligomers

“…Pyrenes have also been employed to decorate TPE instead of being located at the core of the structure [ 67 ]. In this case, the Suzuki coupling between a boronic acid derivative of 2,7-ditertbutylpyrene and 1,1,2,2-tetrakis(4-bromophenyl)ethene furnished oligomer 23 .…”