Conductivity and photoconductivity of undoped and doped Langmuir‐Blodgett films of a polymer with hexaalkoxytriphenylene side‐groups

Langmuir‐Blodgett films from a polymer with triphenylene moieties in the side groups deposited on a quartz substratum with aluminium and gold electrodes show a dark conductivity in the plane of the Langmuir‐Blodgett film. This dark conductivity is increased using gold electrodes as compared with aluminium electrodes. It depends in a superlinear way upon the applied electric field and is not enhanced by oxygen. The dark conductivity can be enhanced by doping the Langmuir‐Blodgett films with iodine but it is not influenced by doping the Langmuir‐Blodgett films with 2,4,7‐trinitro‐9‐fluorenone. Upon excitation in the absorption band of the triphenylene moiety an in‐plane photocurrent, which is enhanced by oxygen, could be observed. Also the photocurrent is enhanced by using gold electrodes. Doping the Langmuir‐Blodgett films with iodine or 2,4,7‐trinitro‐9‐fluorenone quenches the photocurrent. Up to 10 W/m 2 the photocurrent depends linearly upon the intensity of the incident light.