Improvement of photovoltaic performance of solid-state dye-sensitized solar cells by iodine doping in conjugated polymer

The performance of solid-state dye-sensitized solar cells using a conjugated polymer, poly(2-methoxy,5-(2′-ethyl-hexoxy)-1,4-phenylenevinylene) (MEHPPV), was greatly improved by iodine doping in the hole transporting layer. The surface photovoltage spectroscopy (SPS) and electric-field-induced surface photovoltage spectroscopy (EFISPS) study on the undoped and iodine doped MEHPPV films were performed and indicated that iodine doping turned the n-type conduction of MEHPPV to p-type conduction, which was accompanied by an improvement of photocurrent from 27 μA/cm2 to 148 μA/cm2.