CONDUCTING POLYMER SYNTHESIS VIA ION-BEAM-INDUCED PRECURSOR CONVERSION

The poly(paraphenylenevinylene) PPV, conjugated polymer has been deriv ed from a sulfonium salt precursor by ion beam irradiation. A quadrupo le mass spectrometry analysis of the evolved species shows the rapid l oss of the HCl and tetrahydrothiophene groups during irradiation with 100 keV Ne+ indicating the precursor degradation. Rutherford backseatt ering spectrometry confirms the reduction of the sulfur and chlorine c ontent in the PPV film, whereas the infrared spectrum shows that the v ibration mode at 2940 cm(-1) of the sulfonium group has vanished for a 2x10(16) ion fluence. The appearance of the transvinylene peaks, at 3 024 and 965 cm(-1) in PPV, indicates the full conversion of the precur sor into the conjugated polymer for this fluence. The correlation betw een a narrower optical band gap and (by one order of magnitude) higher conductivity of a film implanted with Na+ ions with respect to a Neirradiation shows the doping effect induced by an implantation with el ectronically active species, We conclude to the simultaneous conversio n and doping of the PPV polymer upon ion implantation.