Enhanced photovoltaic performance of dye-sensitized solar cells with TiO2 micro/nano-structures as light scattering layer

Double layered TiO2 micro/nano-structured photo-anodes have been constructed for dye-sensitized solar cells (DSSCs). Mesoporous TiO2 nanoparticles serve as under layer to improve the dye absorption and TiO2 microflowers or nanorod aggregates serve as cover layer to provide prominent light scattering effect as well as electron pathways. The as-prepared architecture was characterized with field emission scanning electron microscopy. The TiO2 microflower scattering layer enhanced the photocurrent of DSSCs due to the increased light absorption by the strong light scattering effect, and reduced electron transfer resistance via the direct electron pathways. Enhanced light scattering effect was observed from TiO2 microflower based cell in the whole visible light range through the UV-Vis and IPCE measurements. Reduced electron transfer resistance was validated by electrochemical impedance test. The contrast experiments between the TiO2 microflowers and TiO2 nanorod aggregates further demonstrated that such open structured TiO2 microflowers are more effective to improve the performance of DSSCs. It is expected that the photo-anode design with TiO2 microflowers as scattering layer will be an alternative approach to improve the performance of DSSCs.