Organic photovoltaic solar cells are thinner and less expensive to produce than conventional solar cells made with inorganic silicon wafers, but they do not convert sunlight into electricity as efficiently.

Yang Yang and colleagues, University of California Los Angeles, USA, have taken advantage of the plasmonic effect — by which metals enhance the absorption of light — to improve the power conversion of organic solar cells. The team incorporated Au nanoparticles into the interconnecting layer of a tandem solar cell. This allowed the plasmonic effect to enhance light absorption of both the top and bottom subcells simultaneously. The efficiency of the tandem solar cell was improved from 5.22 % to 6.24 %, an enhancement ratio of 20 %.

• Plasmonic Polymer Tandem Solar Cell
  J. Yang, J. You, C.-C. Chen, W.-C. Hsu, H. Tan, X. W. Zhang, Z. Hong, Y. Yang,
  ACS Nano 2011.
  DOI: 10.1021/nn202144b