WASHINGTON, Nov. 1, 2017 - The National Renewable Energy Laboratory (NREL) has increased the efficiency of quantum dot solar cells. Discovered in 2010, the cells are the newest technology to convert sunlight to electricity. NREL has increased efficiency up to 13.4 percent, compared to the initial lead sulfide quantum dot solar cells which had an efficiency of 2.9 percent. The improvement came from better understanding of the connectivity between individual quantum dots, better overall device structures and reducing defects in quantum dots. “This voltage, coupled with the material’s bandgap, makes them an ideal candidate for the top layer in a multijunction solar cell,” said Joseph Luther, a senior scientist and project leader in the Chemical Materials and Nanoscience team at NREL. The multijunction approach is often used for space applications where high efficiency is more critical than the cost to make a solar module. The NREL research was funded by the Energy Department’s Office of Science.