UPCONVERTER-ENHANCED MOLECULAR PHOTOVOLTAICS: TOWARDS COST-EFFECTIVE, BROADBAND SOLAR ENERGY CONVERSION
JENNIFER DIONNE AND MICHAEL MCGEHEE
MATERIALS SCIENCE AND ENGINEERING
Molecular and polymeric photovoltaic devices are promising candidates for large-scale, cost-effective solar energy conversion. Unfortunately, their utility is largely limited by their poor solar absorption in the near-infrared region of the solar spectrum. A typical dye cell only absorbs solar photons with energy greater than 1.7 eV, wasting approximately 49% of the solar spectrum.
The conversion efficiency of such devices can be enhanced by adding upconverters, which combine below-bandgap photons to emit above-bandgap photons that can then be absorbed by the cell. An optimized upconverter could significantly boost the efficiency of next-generation molecular and polymeric solar cells, potentially nearing the Shockley-Queisser limit. The Stanford researchers will develop an efficient, inexpensive upconverting material and add that to dye-sensitized solar cells to prove their concept. They expect that the technology could be applied to other kinds of photovoltaic cells as well.