Carbazolyl-substituted triphenyldiamine derivatives as novel photoconductive amorphous molecular materials

Novel branched molecules, N,N′-bis(4-carbazol-9-ylphenyl)-N,N′-diphenyl[1,1′-biphenyl]-4,4′-diamine and N,N′-bis(4-carbazol-9-ylbiphenyl-4′-yl)-N,N′-diphenyl[1,1′-biphenyl]-4,4′-diamine, have been synthesised and found to constitute amorphous molecular materials with glass-transition temperatures (Tg) 69 and 107 °C, respectively. The electron photoemission spectra of the amorphous films have been recorded and the ionisation potentials of 5.38–5.46 eV have been established. The hole drift mobility (μh) of the carbazolyl-substituted triaryldiamines was studied by the time-of-flight technique and was found to be in the range of 10−3 to 10−4 cm2/V s at an applied electric field of 6.4×105 V/cm.