Scientists boosted the significance of tandem polymer solar cells by successfully testing cells with low-bandgap polymers that achieved certified conversion efficiencies of 8.62 ± 0.3% with respect to standard terrestrial reporting conditions. That’s the highest independently measured efficiency for a polymer solar cell, say researchers from the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and UCLA, who co-authored a report in the Feb. 12 issue of Nature Photonics. ...