Sky-blue thermally activated delayed fluorescence material employing a diphenylethyne acceptor for organic light-emitting diodes

Abstract

The strong electronegativity of sp-hybridized carbons, contributed by their large s character (50%), inspired the development of diphenylethyne as an electron acceptor to construct a sky-blue thermally activated delayed fluorescence material, 1,2-bis(4-(10H-phenoxazin-10-yl)phenyl)ethyne (DPE-DPXZ), using 10H-phenoxazine (PXZ) as an electron donor fragment. A sky-blue organic light-emitting diode employing DPE-DPXZ as the emitter demonstrated an external quantum efficiency exceeding 10%. Furthermore, another alkyne derivative, 1,2-bis(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)ethyne (DPE-DDMAc), in combination with 9,9-dimethyl-9,10-dihydroacridine (DMAc) as the donor was also studied to explore the singlet–triplet splitting energy governed by donor–acceptor alternation.