A Novel Family of Boron-Containing Hole-Blocking Amorphous Molecular Materials for Blue- and Blue–Violet-Emitting Organic Electroluminescent Devices

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Abstract

A novel family of amorphous molecular materials that function as hole blockers in organic electroluminescent (EL) devices, tris(2,3,5,6-tetramethylphenyl)borane (TPhB), tris(2,3,5,6-tetramethylbiphenyl-4-yl)borane (TBPhB), tris(2,3,5,6-tetramethyl-1,1′;4′,1″-terphenyl-4-yl)borane (TTPhB), and tris[4-(1,1′;3′,1″-terphenyl-5′-yl)-2,3,5,6-tetramethylphenyl]borane (TTPhPhB), have been designed and synthesized. They readily form stable amorphous glasses with high glass-transition temperatures, and are characterized by reversible cathodic reduction and relatively large HOMO–LUMO energy gaps. High-performance blue- and blue–violet-emitting organic EL devices have been developed using TBPhB, TTPhB, and TTPhPhB as hole blockers and N,N′-di(1-naphthyl)-N,N′-diphenyl[1,1′-biphenyl]-4,4′-diamine, tri(p-terphenyl-4-yl)amine, and N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine as emitters.

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