Dye-sensitized solar cell using novel tandem cell structure

The authors report a new tandem cell structure for improving the short-circuit performance of a dye-sensitized solar cell. Two dye-sensitized nanocrystalline TiO 2 films were placed face-to-face as electrodes. As a counter electrode, a platinum mesh sheet with transmittance was inserted between the electrodes. Two TiO 2 anodes were connected in parallel with each other and in series with the Pt-mesh sheet cathode. Because the current density of the two TiO 2 anodes was added, the conversion efficiency was improved from 1.8% to 3.9%. The light energy absorption model in the front and back electrodes well described the output of each electrode. The front electrode thickness was increased according to the model; therefore, the efficiency of the novel tandem cell was improved by up to 4.7% for the thickness of 7.8 µm.