Fabrication of iodine-doped pentacene thin films for organic thermoelectric devices

We investigate the relation between the morphology and thermoelectric properties of iodine-doped pentacene thin films grown on the glass substrate. The electrical conductivity and thermoelectric power factor are enhanced with decreasing the film thickness and growth temperature due to the volumetric increase in the thin film phase relative to the bulk phase in the film. The 115 and 190 nm thin films grown at room temperature, whose majority phase is the thin film phase, exhibit high power factor of 1.3×10−5 W m−1 K−2. Also, we demonstrate an improved stability of thermoelectric properties by covering the iodine-doped film with a polyimide tape.