Efficient exciplex emission from intramolecular charge transfer material

• New exciplexes formed between DMAC-DPS and a series of electron donor and acceptors have been systematically demonstrated.
• DMAC-DPS:PO-T2T exciplex offered EQE, luminance and current efficiency of 9.08%, 35,000 cd/m2 and 30 cd/A, respectively.
• 6 ± 1 wt.% DMAC-DPS:PO-T2T exciplex offered EQE of 8%.

New exciplexes formed between a typical intramolecular charge transfer (ICT) material (bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (DMAC-DPS)) and a series of electron donor and acceptors in donor:acceptor system have been systematically demonstrated. It is found that such ICT materials could form exciplex with both standalone electron donor and acceptor materials with itself as acceptor and donor components, which is based on the presence of both donor and acceptor species in the ICT material. The emission spectra of exciplex OLEDs based on ICT materials could be regularly tuned ranging from blue to yellow color by changing energy level alignment between ICT and standalone donor/acceptor materials. Among these exciplexes, DMAC-DPS:PO-T2T combination offered the highest exciplex EL performance, with its peak external quantum efficiency, luminance and current efficiency of 9.08%, 35,000 cd/m2 and 30 cd/A, respectively. On the other hand, we also found that the exciplex efficiency was insensitive with the weight ratio between ICT material and acceptor, which means ‘doping’ of ICT material into the acceptor. Our finding extend the usage and selection scope of the TADF material.

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