Efficient near ultraviolet organic light-emitting devices based on star-configured carbazole emitters

Efficient near ultraviolet organic light-emitting devices with the maximum external quantum efficiency of 3.3% were fabricated using novel star-configurated carbazole derivatives (MTPC) as emitters. Beside the main peak wavelength at 408 nm, an obvious longer wavelength tail with peak emission at 493 nm was observed, which was certified because of the emission of exciplex between MTPC and TPBI exciton confiner. Our results clearly suggest that the star-configurated carbazole derivatives are potential to be served as high efficient near ultraviolet emitters and as hosts for visible color dopant.