Electro-active monomers and polymers containing 3-arylcarbazol-9-yl fragments

Abstract

Monomers and polymers containing 3-arylcarbazol-9-yl fragments were synthesized. The materials were examined by various techniques including differential scanning calorimetry, thermogravimetry, electron photoemission spectrometry and xerographic time of flight technique. The electron photoemission spectra of the layers of the derivatives showed ionization potentials of 5.35–5.45 eV. Hole drift mobilities in the layers of the monomers dispersed in polymeric host bisphenol Z polycarbonate (50%) range from 10 −6 to 1.6 × 10 −5 cm 2 V −1 s −1 at high electric fields at room temperature. The synthesized polymers have been tested as hole-transporting materials in bilayer OLEDs with Alq 3 as the emitter. The device with polymer containing (1-naphtyl)phenylamino substituted carbazolyl fragments exhibited the best overall performance with turn-on voltage of ∼3 V, a maximum photometric efficiency of 4.1 cd/A and maximum brightness of ca. 22,900 cd/m 2.