3,9′-Bicarbazole-Based Compounds with Reactive Functional Groups as Potential Cross-Linkable High Triplet Energy Hole-Transporting Materials

Abstract

New oxiranyl-substituted derivatives of 3,9′-bicarbazole were synthesized by synthetic route involving Ullmann coupling, Vilsmeier formylation, reduction with sodium borohydride and the interaction of hydroxymethyl derivatives with 2-(chloromethyl)oxirane. The optical, photophysical and photoelectrical properties of the newly synthesized materials were studied. The electron photoemission spectra of the materials revealed the ionization potentials ranging range from 5.55 to 5.70 eV. Time-of-flight hole drift mobilities of bisphenol Z polycarbonate doped with 50 wt.% 3,9′-bicarbazole -based compounds exceed 10⁻⁶ cm²/V · s.

Keywords:

• Carbazole derivatives
• hole drift mobility
• ionization potential
• oxiranyl functionalized

Acknowledgment

Financial support of this research by the Research Council of Lithuania (grant No. TAP67/2010) is gratefully acknowledged. Dr. V. Gaidelis is thanked for the help in ionization potential measurements.