Fabrication of highly efficient polythiophene-sensitized metal oxide photovoltaic cells

Poly(3-thiophenylacetic acid)-polymer-sensitized photoelectrochemical cells comprising of either mesoporous TiO2 or SnO2-ZnO electrodes and the electrolyte consisting with redox complex (I3−/I−) were fabricated and characterized. The addition of ionic liquid, 1-methyl- 3-n-hexylimidazolium iodide, into the electrolyte drastically enhanced the cell performance. The cells consisting of the nanoporous TiO2 electrodes showed the incident photon to current conversion efficiency as high as 60% (at 430 nm), while the highest overall power conversion efficiency was ∼2.4% under the irradiance of 100 mW cm−2 (air mass 1.5). The overall efficiency of the cells with nanoporous SnO2-ZnO electrodes was ∼1.5% under the same illumination.