Nanostructured photoelectrodes and polymeric nanointerfaces engineering: the critical transition from rigid to flexible dye-sensitized solar cells

In view of obtaining light-weight, wearable and low-cost supply systems for low power electronics, the integration of dye-sensitized solar cells (DSSCs) in portable devices represents an important target for the scientific community. Nevertheless, some modifications of the standard DSSC architecture are mandatory: first and foremost the flexibilization of the electrodes and the optimization of the electrodes/electrolyte nanointerfaces upon bending. In this respect, vertically aligned TiO2 nanotubes (NTs) are here presented as suitable photoelectrode material, in combination with UV-curable polymer electrolyte gel or membranes. TiO2 NTs are grown both on flexible meshes and metallic foils, accurately controlling their size and transparency by properly modifying the preparation process. The use of specifically selected polymer electrolytes assures both higher durability with respect to standard liquid electrolyte-cells, and suitable nanointerface with the TiO2 photoelectrode, thus limiting the charge recombination phenomena. The third important modification is represented by the cell architecture: the geometries proposed in this work satisfy the requirements in terms of efficiency, stability, low cost and flexibility.