Efficient charge transport in a solid electrolyte with percolated Pt for solid-state fiber dye-sensitized solar cells

Abstract

Percolation effect is introduced in the fabrication of solid-state electrolytes using a metal sputtering process on the surface of a lithium-bis(trifluoromethane)sulfonamide film. The percolation effect provides efficient electron extraction through the solid electrolyte surface. However, the additional presence of metal islands could limit the exciton harvest owing to the lowering of the transparency of the solar cell. To maximize the advantages of percolation-induced charge transportation, the thicknesses of percolation layers based on Pt and Au are precisely controlled under the trade-off between transparency and conductivity. The presence of a 1–3 nm thin percolation layer not only enhances the conductivity of the film but also enhances the efficiency of the reduction of redox reactions at the electrolyte. The origin of enhancements is evaluated by transmission line measurements, cyclic voltammetry, and electrochemical impedance spectroscopy. Because of the better electron distribution in the counter electrode and solid electrolyte interface, the power conversion efficiency of Pt-sputtered S-FDSSCs (solid state fiber dye-sensitized solar cells) increases by 30% instead of reference S-FDSSCs. Additionally, better series resistance ensures that S-FDSSCs maintain 80% efficiency under 500 times the bending fold. By following standard terrestrial for thin-film photovoltaics, capsulated S-FDSSCs can maintain about 60% efficiency in artificial environment tests at 85% relative humidity and 85 °C.