While organic photovoltaic solar cells have a wide range of potential applications, they still lag behind conventional solar cells in their ability to efficiently convert sunlight into electricity. Now, researchers from the University of California Los Angeles, United States, along with their colleagues from China and Japan, have found that incorporating gold nanoparticles into these organic solar cells can significantly improve the cells’ power conversion. The gold nanoparticles, which are sandwiched between two light-absorbing subcells in a tandem polymer solar cell, take advantage of the plasmonic effect, by which metal helps to enhance the absorption of sunlight. According to Yang Yang, a professor of materials science and engineering, “We have successfully demonstrated a highly efficient plasmonic polymer tandem solar cell by simply incorporating gold nanoparticles layer between two subcells. The plasmonic effect happening in the middle of the interconnecting layer can enhance both the top and bottom subcells simultaneously — a ‘sweet spot’ — leading to an improvement in the power conversion efficiency of the tandem solar cell from 5.22 percent to 6.24 percent. The enhancement ratio is as high as 20 percent.” The team published their findings in the journal ACS Nano.
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