A new type of p-doping for polyacetylene

Summary form only given. We report here a new p-doping for polyacetylene which seems to be very promizing. The new dopant is the ion: (CF/sub 3/SO/sub 2/)/sub 2/N/sub -/ (TFSI). It is possible to use various counter-ions in the salt and make so to performe electrochemical or chemical doping. For chemical doping we used the copper salt in a CH/sub 3/CN solution and observed a swelling and a color change of the sample. For electrochemical doping we used the lead or the lithium salt in various solvents such as CH/sub 3/CN or (C/sub 2/H/sub 5/)/sub 2/NSO/sub 2/N(C/sub 2/H/sub 5/)/sub 2/. With electrochemical doping we reached a maximum doping level close to 8% and the conducdvity increased up to 20 S/cm. A spontaneous slow dedoping process occured. We performed Raman measurements with various wawelenghts and we observed the characteristic peaks of cis and trans polyacetylene simultaneously. This behaviour can be interpreted as the result of an inhomogenous, doping of the sample. More surprising is the photoluminescence of the systems which does not depends on the way the samples were doped (electrochemically or chemicaly). This photoluminescence is also independent on the wawelenght: we observed this behaviour with an energy between 1,7 eV for a 6471 /spl Aring/ exciting line and 1,975 eV for a 4880 /spl Aring/ exciting line. We have also performed EPR and Infra-Red Spectroscopy experiments to complete our study of these new p-doped samples.