Researchers at UCLA’s school of engineering and UCLA’s California Nanosystems Institute (CNSI) have developed a device to convert sunlight into electricity efficiently and cost effectively using organic polymers. UCLA’s Yang Yang’s research team has built a device with a new 'tandem' structure for power-conversion. In July 2011, the device had 8.62 percent power-conversion efficiency. After incorporating infrared-absorbing polymer material into the device, its power-conversion efficiency dramatically increased to 10.6 percent, reaching a new world record. The recipe for this record-breaking tandem polymer solar cell included stacking photoactive layers with complementary absorption spectra. Cells with varying absorption bands allow a broader spectrum of solar radiation to be harvested. It is important to note, however, that compatible materials must be used in the tandem cells to ensure efficient light harvesting.