Nanoscale size effects on photoconductivity of semiconducting polymer thin films

Bilayer polymer photoreceptors containing a trap-free tri-p-tolylamine-doped polycarbonate (TTA:PC) layer and a conjugated polymer layer are used to study nanoscale size effects in electronic polymers. A 3-fold enhancement of photogeneration quantum efficiency is observed as the thickness of poly(2,5-pyridylenebenzo-bisthiazole) (PPyBT) is reduced from 100 to 10 nm. The nanometer size effects originate from the small exciton diffusion lengths and the interfacial nature of the photocarrier generation.