Characterization of 6PV phenylene vinylene oligomer thin films

Investigations of phenylene vinylene oligomer thin films with 7 phenyl, 6 vinyl units (6PV) have been performed by optical and electrical measurements, The optical characterizations including infrared, Raman and UV-VIS spectroscopies were discussed by comparing the results with those obtained in poly(p-phenylene vinylene) (PPV). The electrical properties of oligomer based diodes were studied by measuring the current-voltage-temperature characteristics and the thermally stimulated currents (TSC). At high fields, tunneling of carriers through the interfacial barrier would occur while at lower fields, two distinct temperature ranges were observed. In the high temperature range (> 250 K), a field assisted mechanism occurs involving localized states in the oligomer bulk whereas in the low temperature range, hopping conduction is probable. The TSC spectrum shows two relaxation peaks at 219 and 261 K which correspond to trap depths of 0.4 and 0.55 eV. The deep traps appeared as a characteristic of phenylenevinylene oligomers. (C) 1998 Elsevier Science B.V.