PICOSECOND STUDIES OF ULTRAFAST PROCESSES IN PHOTOCONDUCTING PHENYLATED POLY(PHENYLENE VINYLENES)

Fast processes in phenylated poly(phenylene vinylenes) (P-PPVs) after absorption of ultrashort UV light pulses were studied by the Auston-sw itch technique, time-correlated single-photon counting and excite-and- probe measurements in the nanosecond and picosecond time regions. The temporal behaviour of the transient photocurrent and the fluorescence are shown to be very similar. Both kinetics contain a nanosecond and a picosecond time component. The transient absorption bands observed wi th 6 ps time resolution show wavelength-dependent rise and decay times . From these results we infer that singly and doubly charged carriers are formed in P-PPV within 100 ps. In the nanosecond time range multip le trapping of carriers dominates.