3,3 0 -Di(9-(4-butylphenyl)carbazyl) and 3,3 0 -di(9-ethylcarbazyl)-based hydrazones were synthesized by the multi-step synthetic route including oxidative dimerization of 9-(4-butylphenyl)carbazole and 9-ethylcarbazole, formylation of the dimmers obtained and the reactions of the formyl derivatives with different hydrazines. The chemical structure of the compounds was confirmed by 1 HNMR, IR and mass spectroscopy. The hydrazones synthesized form stable glasses with the glass transition temperatures exceeding 140 C. The values of ionisation potentials measured by electron photoemission technique are in the range of 5,21-5,4 eV. The hole drift mobilities in the films of the 50% solid solutions of the hydrazones in Financial support from Samsung Electronics and from the Lithuanian State Science and Studies foundation is gratefully acknowledged. 95=[407]bisphenol Z polycarbonate established by the xerographic time-of-flight technique exceed 10 À5 cm 2 =Vs at high electric fields.

No abstract

No abstract

No abstract

BACKGROUND: Carbazole derivatives are well known to exhibit interesting electro-and photo-active properties due to their hole-transporting ability, strong absorption in the ultraviolet spectral region and blue-light emission. One of the most widely studied materials among carbazole-containing oligomers is poly[9-(2,3-epoxypropyl)carbazole] (PEPK). The main field of application of this oligomer is electrophotographic microfilming. It is also used for the manufacture of multicolour slides and in the photothermoplastic recording of information. Unfortunately, due to its high ionization potential, which reaches 5.86 eV, the possibilities of application of this compound in optoelectronic devices are rather limited. RESULTS: PEPK-based charge transporting oligomers, incorporating hydrazone moieties, are reported. The oligomers were prepared by chemical modification of PEPK. The materials obtained were examined using various techniques including differential scanning calorimetry and ultraviolet, infrared and NMR spectroscopy. Electron photoemission spectra of layers of the synthesized oligomers showed ionization potentials (I p ) in the range 5.4-5.5 eV. CONCLUSION:The synthesized oligomers possess a larger π -conjugated system and show ionization potentials of ca 5.4 eV. Therefore, they are more suitable for use in optoelectronic devices with quicker photoresponse than unmodified PEPK.