Host Materials For Electrophosphorescent Devices Research Articles

Carbazole/oligofluorene end-capped hexanes: solution-processable host materials for phosphorescent organic light-emitting diodes

High-performance solution-processable host materials for electrophosphorescent devices have been developed via a new method of aromatic double end-capping alkylization.

“Click” Synthesis of a Bipolar Dendrimer as a Host Material for Electrophosphorescent Devices

A new solution-processable bipolar dendrimer with carbazole units as hole-transporting units and oxadiazole units as electron-transporting units was efficiently synthesized based on a convergent approach by alternation of a Cu-catalyzed azide/alkyne cycloaddition reaction and Williamson ether synthesis. The orthogonal chemistry completely avoided protection and activation of the focal points in the process of dendrimer synthesis. The dendrimer showed a wide bandgap and good thermal stability. Electrophosphorescent devices with the configuration ITO/PEDOT:PSS/bipolar dendrimer: Ir(ppy)(3)/TPBI/LiF/Al were fabricated. The devices showed a maximum current efficiency of 16.8 cd.A(-1), a maximum power efficiency of 4.22 lm.W-1 and an external quantum efficiency of 5.7%.

A New Host Material for Electrophosphorescent Devices

A New Host Material for Electrophosphorescent Devices

Well Defined Carbazol-3,9-Diyl Based Oligomers as Host Materials for Organic Electro-Phosphorescent Devices

Well defined carbazol-3,9-diyl-based derivatives as host materials for electro-phosphorescent devices have been synthesized by the modified Ullmann reaction as a key step. The full characterization of their structure by mass spectrometry, infrared absorption and proton magnetic resonance spectroscopy is presented. The amorphous compounds with glass transition temperatures of 103–154°C possess high thermal stability with onset decomposition temperatures exceeding 360°C. Conjugation of the 3,9-linked systems is rather confined within one carbazole unit, retaining large triplet energies suitable for green and red electro-phosphorescence. Using the new host material, efficient green phosphorescent organic light emitting diodes was demonstrated.