Efficient Solid Emitterswith Aggregation-InducedEmission and Intramolecular Charge Transfer Characteristics: MolecularDesign, Synthesis, Photophysical Behaviors, and OLED Application.

Emissive electron donor–acceptor (D–A)conjugateshave a wide variety of applications in biophotonics, two-photon absorptionmaterials, organic lasers, long wavelength emitters, and so forth.However, it is still a challenge to synthesize high solid-state efficiencyD–A structured emitters due to the notorious aggregation-causedquenching (ACQ) effect. Though some D–A systems are reportedto show aggregation-induced emission (AIE) behaviors, most are onlyselectively AIE-active in highly polar solvents, showing decreasedsolid-sate emission efficiencies compared to those in nonpolar solvents.Here we report the triphenylamine (TPA) and 2,3,3-triphenylacrylonitrile(TPAN) based D–A architectures, namely, TPA3TPAN and DTPA4TPAN.Decoration of arylamines with TPAN changes their emission behaviorsfrom ACQ to AIE, making resulting TPA3TPAN and DTPA4TPAN nonluminescentin common solvents but highly emissive when aggregated as nanoparticles,solid powders, and thin films owing to their highly twisted configurations.Both compounds also display a bathochromic effect due to their intramolecularcharge transfer (ICT) attribute. Combined ICT and AIE features renderTPA3TPAN and DTPA4TPAN intense solid yellow emitters with quantumefficiencies of 33.2% and 38.2%, respectively. They are also thermallyand morphologically stable, with decomposition and glass transitiontemperatures (Td/Tg) being 365/127 and 377/141 °C, respectively. Multilayerelectroluminescence (EL) devices are constructed, which emit yellowEL with maximum luminance, current, power, and external quantum efficienciesup to 3101 cd/m2, 6.16 cd/A, 2.64 lm/W, and 2.18%, respectively.These results indicate that it is promising to fabricate high efficiencyAIE-ICT luminogens with tunable emissions through rational combinationand modulation of propeller-like donors and/or acceptors, thus pavingthe way for their biophotonic and optoelectronic applications. [ABSTRACT FROM AUTHOR]