Highly Efficient Dye-Sensitized Solar Cells with Gel-Coated Graphene and Graphene/Carbon Nanotube Composites as the Counter Electrode

J. Ouyang
National University of Singapore, SG

Keywords: dye-sensitized solar cells, graphen, carbon nanotubes

Summary:

Dye-sensitized solar cells (DSCs) are promising to be the next-generation solar cells arising from their high light-to-electricity conversion efficiency and low fabrication cost. During the photon-to-electron conversions process, the regeneration of iodide from triiodide at the counter electrode is an important step. It requires the counter electrode conductive and catalytic for the reduction of triiodide. Platinum (Pt) is conventionally the popular material for the counter electrode of DSCs. The most efficient Pt counter electrode is fabricated by pyrolysis of Pt precursors at a temperature higher than 380 ◦C. However, such a high-temperature process prevents the Pt deposition on flexible substrates like polymers. In addition, the noble Pt significantly increases the cost of DSCs. Therefore, great effort has been made in the search for new materials as the counter electrode of DSCs. Here, we report highly efficient DSCs with graphene or graphene/carbon nanotube composites as the counter electrode. Graphene and graphene/carbon nanotube composites are fabricated by gel coating. The photovoltaic efficiencies are comparable to that with Pt as the counter electrode.