Doping of oligo(phenyl acetylene) with iodine vapour

The doping with I2-vapour and dopant effusion of thin films of conjugated oligomers are reported in this work. The layers have been created solvent-free, by initiated chemical vapour deposition (iCVD). FTIR spectra show an interaction of the dopant with the phenyl ring of the oligomer. Reflectance/transmittance measurements showed a saturation of the dopant in the 400 nm thick layers after 40 min. The films change from transparent to brown-green in the doping process and show a drastic increase in conductivity. The material is quite easily processable and can be grown at an adequate rate (3.5 nm/min) for thin film device applications.