Highly Twisted α-Diketone-Based Thermally Activated Delayed Fluorescence Emitters and their use in Organic Light-Emitting Diodes

We have designed a highly twisted small TADF emitter PXZ-α-DK based on an -diketone (α-DK) as strong acceptor and phenoxazine (PXZ) donor to obtain red-shifted emission in comparison the equivalent linked 9,9-dimethyl-9,10-dihydroacridine (DMAC). The shows at 586 nm DMAC-α-DK 548 1,3-bis(N-carbazolyl)benzene (mCP) host 1.5 wt% doping of emitter, with short-delayed lifetimes 6.9 μs for 7.6 DMAC-α-DK. OLEDs fabricated using these emitters show green electroluminescence 555 DMAC-α-DK, maximum external quantum efficiency, EQEmax, 6.3%, orange 585 PXZ-α-DK, EQEmax 0.8%. corroborate optoelectronic properties DFT calculations.