Improved conversion efficiency of dye-sensitized solar cells by using novel complex nanostructured TiO2 electrodes

A novel complex nanostructured TiO2 electrode and fabrication process were proposed and demonstrated to improve the performance of dye-sensitized solar cells (DSSCs). In the proposed process, a nanoporous TiO2 layer was firstly fabricated on the FTO (fluorine-doped tin oxide) conducting substrate by an anodization process, then a nanoparticulate TiO2 film was deposited on the nanoporous TiO2 layer by the screen printed method to form the complex nanostructured TiO2 electrode. The experiments demonstrated that the nanoporous TiO2 layer can enhance the light scattering, decrease the contact resistance between TiO2 electrode and FTO, and suppress the recombination of I-3(-) ion with the injected electrons of FTO. The process variables are crucial to obtain the optimized performance of DSSCs. By adopting the optimized process, improved conversion efficiency of DSSCs was achieved at AM 1.5 sunlight.