NREL and Mitsubishi boast new efficiency records

Researchers at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have achieved conversion efficiency world record for a CIGS (copper indium gallium diselenide) thin-film solar cell of 19.9 percent in testing at a lab. This compares favorably to a conversion efficiency in certain multi-crystalline solar cells of 20.3 percent, providing an important milestone for the coming-of-age of the newer technologies of thin-film vis-a-vis silicon based solar cells. According to NREL, the record was achieved by improvements in the quality of the material applied during the manufacturing process, boosting the power output from the cell.

Meanwhile, Mitsubishi Electric Corporation claims it has set a new world record with a photoelectric conversion efficiency rate of 18.6 percent in a 150-millimeter square practical use multi-crystalline silicon solar cell, an improvement of 0.6 percent over the company's previous record. The company claims it achieved the new record by (1) adding a low reflectivity surface texture on the multi-crystalline silicon wafer, (2) optimizing the p-n junction to increase electric current generation and (3) developing a process to print electrodes on the surface of the silicon (metallization) to reduce shade loss of front grid electrodes. Such technological adaptations contribute to higher efficiency in small installations such as narrow roofs.