2,7-Bis(diarylamino)-9,9-dimethylfluorenes as Hole-Transport Materials for Organic Light-Emitting Diodes†

摘要: 2,7-Bis(p-methoxyphenyl-m′-tolylamino)-9,9-dimethylfluorene (1′), 2,7-bis(phenyl-m′-tolylamino)-9,9-dimethylfluorene (2′) and 2,7-bis(p-fluorophenyl-m′-tolylamino)-9,9-dimethylfluorene (3′) have been synthesized using the palladium-catalyzed reaction of appropriate diarylamines with 2,7-dibromo-9,9-dimethylfluorene. These molecules glass-transition temperatures 15–20 °C higher than those for their biphenyl-bridged analogues, are 0.11–0.14 V more readily oxidized. Fluorescence spectra fluorescence quantum yields dimethylfluorene-bridged species similar, but peaks absorption 1′–3′ considerably red-shifted relative to analogues. Time-of-flight hole mobilities 1′–3′/polystyrene blends in a similar range Analysis according disorder formalism parameters rather biphenyl species, somewhat lower zero-field mobility values. Density functional theory (DFT) calculations suggest that enforced planarization fluorene bridge leads slightly larger reorganization energy neutral/cation electron-exchange system. Organic light-emitting diodes fabricated as hole-transport layer tris(8-hydroxy quinoline)aluminium electron-transport lumophore. Device performance shows correlation ionization potential amine materials paralleling seen biphenyl-based systems, show comparable potential.