Effect of the chromophores structures on the performance of solid-state dye sensitized solar cells

The effect of metal-free chromophores on dye-sensitized solar cell performance is investigated. Solid state dye-sensitized solar cells (ssDSCs) using different molecular sensitizers based on triphenylamine (TPA) with thiophene linkers and different alkyl chain in the donor unit have been characterized using impedance spectroscopy (IS). We show that different molecular structures play a fundamental role on solar cell performance, by the effect produced on TiO2 conduction band position and in the recombination rate. Dye structure and its electronic properties are the main factors that control the recombination, the capacitance and the efficiency of the cells. A clear trend between the performance of the cell and the optimization level of the blocking effect of the dye structure has been identified in the solid state solar cells with Spiro-OMeTAD hole conductor.This work was ̄nancially supported by the Swedish Energy Agency, the Knut and Alice Wallenberg Foundation, National Natural Science Foundation of China (21120102036, 91233201), National Basic Research Program of China (2009CB220009) and China Scholarship Council (CSC). We acknowledge support by a project from Generalitat Valenciana (ISIC/2012/008). H. Tian would like to thank Sill en scholarship for supporting his visiting research in UJI and also thank Rafael S anchez, Victoria Gonz alez and others from GDFO for their kind help with this research work