(August,03) Spectrolab, a subsidiary of The Boeing Company, enhances a triple junction photovoltaic cell’s efficiency resulting in 36 percent of concentrated sunlight converted into electricity. Spectrolab’s achievement is a necessary step to achieve one of the U.S. Department of Energy’s major PV initiative goals, to develop solar modules that convert more than 33 percent of the sun’s energy into electricity as targeted in the High Performance PV Project.
“The modified cell design better suits the terrestrial solar spectrum and opens the path for higher performance terrestrial concentrators,” said David Lillington, President of Spectrolab. “And, because the terrestrial cell we have developed is similar to our conventional space cells, it can be implemented in production, and manufactured in very high volumes with minimal impact to production flow.”
A significant advantage of concentrator systems is that fewer solar cells are required to achieve a specific power output, thus replacing large areas of semiconductor materials with relatively inexpensive optics that provide optical concentration. The slightly high cost of multijunction cells is offset by the use of fewer cells. Due to the higher efficiency of multijunction cells used in the concentrator modules, only a small fraction of the cell area is required to generate the same power output compared to crystalline silicon or thin-film flat-plate modules.
The terrestrial solar cell is a modified version of Spectrolab’s Improved Triple Junction (ITJ) space solar cell.
The terrestrial concentrator cell, measuring approximately one-quarter of a square centimeter in area, was fabricated and tested at Spectrolab and then re-measured at the National Renewable Energy Laboratory (NREL) in Golden, Colorado.