Structural characterization and electrical conductivity of poly(phenylethynyl) copper doped with iodine and 2,3-dichloro-5,6-dicyano-p-benzoquinone

Abstract

Poly(phenylethynyl)copper was prepared by reacting phenylacetylene with Cu + ions. Its dc conductivity drastically increases on doping with iodine and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ). An investigation using IR and UV spectroscopy, X-ray diffraction and Solid State NMR revealed that on iodine doping structural changes occur caused by a reaction between Cu(I) and the dopant. On the contrary, on doping with DDQ the structure is preserved. The large conductivity increase with the latter dopant originates from charge transfer between the polymer chain (donor) and DDQ (acceptor), evidenced by a transformation from a quinone into a semiquinone structure of the DDQ molecule.