Efficiency improvement in solid-state-dye-sensitized photovoltaics with an amphiphilic Ruthenium-dye

We report a solid-state-dye-sensitized solar cell with an efficiency of 4% over the standard air mass 1.5 spectrum (100mW∕cm2). This was made possible by using an amphiphilic dye with hydrophobic spacers. We attribute the performance to the self-assembly of the dye to a dense layer on the TiO2 surface with its carboxylate groups as anchors and with its hydrophobic isolating chains as blocking layer between hole conductor and TiO2. In addition we studied the dependence of the thickness of the nanoporous TiO2 layer and the device performance. These results show the high potential for solid-state-dye-sensitized solar cells to compete with amorphous silicon cells as low-cost alternative.