Impacts of intramolecular B–N coordination on photoluminescence, electronic structure and electroluminescence of tetraphenylethene-based luminogens

• Two tetraphenylethene-based luminogens with B–N coordination are synthesized.
• They are thermally stable and show aggregation-induced emission.
• The B–N coordination improves emission property and lowers LUMO energy levels.
• The B–N coordination is conducive to electroluminescent property of the luminogens.

N,C-Chelate four-coordinate organoborons are a new class of luminogenic materials but the impacts of intramolecular B–N coordination on the optoelectronic properties of the luminogens are not fully understood. In this work, B–N coordination is grafted onto two tetraphenylethene (TPE)-based luminogens and the thermal stabilities, optical properties and electronic structures of the generated organoborons are investigated and compared with those of counterparts without B–N coordination. Both luminogens are thermally stable and show aggregation-induced emission. The presence of B–N coordination not only improves photoluminescent property of the luminogens, affording excellent solid-state fluorescence quantum yields up to unity, but also lowers the LUMO energy levels, owing to pπ–π* conjugation. The application of both organoborons as emitters for organic light-emitting diodes is evaluated. The devices of them exhibit superior electroluminescent efficiencies to the devices of counterparts, demonstrating that B–N coordination is conducive to electroluminescent property of the luminogens.

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