Dye-sensitized solar cells consisting of dye-bilayer structure stained with two dyes for harvesting light of wide range of wavelength

Dye-sensitized solar cells (DSCs) containing dye-bilayer structure of black dye and NK3705 (3-carboxymethyl-5-[3-(4-sulfobutyl)-2(3H)-bezothiazolylidene]-2-thioxo-4-thiazolidinone, sodium salt) in one TiO(2) layer (2-TiO-BD-NK) are reported. The 2-TiO-BD-NK structure was fabricated by staining one TiO(2) layer with these two dyes, step by step, under a pressurized CO(2) condition. The dye-bilayer structure was observed by using a confocal laser scanning microscope. The short circuit current (J(sc)) and the incident photon to current efficiency of the cell (DSC-2-TiO-BD-NK) was almost the sum of those of DSC stained with black dye only (DSC-1-TiO-BD) and DSC stained with NK3705 only (DSC-1-TiO-NK). (C) 2008 American Institute of Physics.