Solid-state oligomer electrolyte with amine–acid interaction for dye-sensitized solar cells

A pair of poly(ethylene glycol) oligomers with terminal groups capable of providing amine–acid interactions are used in dye-sensitized solar cells (DSSCs) as an electrolyte that can be easily solidified at room temperature. In spite of its solidity, the oligomer electrolyte has high ionic diffusion and good permeability into the nanopores of a TiO2 electrode. The electron diffusion coefficient and lifetime in a photoelectrode are largely affected by the adsorptive interaction between cations and the TiO2 surface. The energy-conversion efficiency of DSSCs using the oligomer electrolyte is greater than 4.5%. Long-term storage at room temperature demonstrates that the stability of the oligomer electrolyte system is superior to that of a volatile solvent electrolyte.