Porous, platinum nanoparticle-adsorbed carbon nanotube yarns for efficient fiber solar cells.

Pt is a classical catalyst that has been extensively used in fuel cell and solar cell electrodes, owing to its high catalytic activity, good conductivity, and stability. In conventional fiber-shaped solar cells, solid Pt wires are usually adopted as the electrode material. Here, we report a Pt nanoparticle-adsorbed carbon nanotube yarn made by solution adsorption and yarn spinning processes, with uniformly dispersed Pt nanoparticles through the porous nanotube network. We have fabricated TiO(2)-based dye-sensitized fiber solar cells with a Pt-nanotube hybrid yarn as counter electrode and achieved a power conversion efficiency of 4.85% under standard illumination (AM1.5, 100 mW/cm(2)), comparable to the same type of fiber cells with a Pt wire electrode (4.23%). Adsorption of Pt nanoparticles within a porous nanotube yarn results in enhanced Pt-electrolyte interfacial area and significantly reduced charge-transfer resistance across the electrolyte interface, compared to a pure nanotube yarn or Pt wire. Our porous Pt-nanotube hybrid yarns have the potential to reduce the use of noble metals, lower the device weight, and improve the solar cell efficiency.