Novel hole-transporting materials based on 1,4-bis(carbazolyl)benzene for organic light-emitting devices

Abstract

Novel hole-transporting molecules containing 1,4-bis(carbazolyl)benzene as a central unit and different numbers of diphenylamine moieties as the peripheral groups have been synthesized and characterized. These compounds are thermally stable with high glass transition temperatures of 141-157 uC and exhibit chemically reversible redox processes. Their amorphous state stability and hole transport properties can be significantly improved by increasing the number of diphenylamine moieties in the outer part and by controlling the symmetry of the carbazole-based molecules. These compounds can be used as good hole-transporting materials for organic electroluminescent (EL) devices. The device performance based on tri-and tetra-substituted carbazole derivatives is comparable to that of a typical 4,4'-bis[N-(1-naphthyl)-N-phenylamino] biphenyl (NPB)-based device.

Highly Efficient Green‐Emitting Phosphorescent Iridium Dendrimers Based on Carbazole Dendrons

“…The compound 1-(4′-bromophenyl)-2-phenyl-1H-benzoimidazole was prepared by condensation of N-(4-bromophenyl)-o-phenylenediamine with benzaldehyde. Then it was treated with the carbazole dendrons via the Ulmann reaction [25] to give LG1 and LG2, respectively. The dendrimers with an iridium core were prepared according to a modified, two-step approach, [26] as illustrated in Scheme 1a.…”

“…PEDOT:PSS was obtained from H. C. Starck Baytron. TCCz was prepared as previously described [25] and TBPI was prepared following a literature method [30].…”

Fluorene‐Carbazole Dendrimers: Synthesis, Thermal, Photophysical and Electroluminescent Device Properties

“…Coupling of 2,7-dibromo-9,9-dioctyl-9 H -fl uorene in excess carbazole under ( ∼ 65 ° C for TPD and ∼ 100 ° C for NPB), ease of crystallization and unsatisfactory morphological stability. [ 5,6 ] Recently, AHTMs with high T g such as dendritic carbazole molecules with a fl uorene core, [ 7,8 ] 1,4-bis( N-carbazolyl)benzene as a central unit and different numbers of diphenylamine moieties as the peripheral group, [ 9 ] 1,3,5-tris(2-(9-ethylcarbazolyl-3)ethylene)benzene, [ 10 ] 4,4 ′ ,4 ′ ′ -tri( N -dibenzocarbazolyl)triphenylamine [ 11 ] and monodisperse carbazole-based oligomers, [ 12 ] have been reported.…”

Ruthenium (II) polypyridyl complexes based on bipyridine and two novel diimine ligands with carrier-transporting unit: synthesis, photoluminescence and redox properties

“…The ligand precursors 2-(4-bromophenyl)-5-phenyl-1,3,4-oxadiazole (1) and 1-carbazolyl-4-bromobenzene (2) were synthesized as described in literatures [32,33]. Ru(bpy) 2 Cl 2 $2H 2 O was synthesized in advance [34] to be used as the precursor to synthesize all the ruthenium (II) complexes.…”