Solar Cell Sets World Efficiency Record

[agent46]

Solar Cell Sets World Efficiency Record At 40.8 Percent

ScienceDaily (Sep. 30, 2008) — Scientists at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have set a world record in solar cell efficiency with a photovoltaic device that converts 40.8 percent of the light that hits it into electricity. This is the highest confirmed efficiency of any photovoltaic device to date.

The inverted metamorphic triple-junction solar cell was designed, fabricated and independently measured at NREL. The 40.8 percent efficiency was measured under concentrated light of 326 suns. One sun is about the amount of light that typically hits Earth on a sunny day. The new cell is a natural candidate for the space satellite market and for terrestrial concentrated photovoltaic arrays, which use lenses or mirrors to focus sunlight onto the solar cells.

The new solar cell differs significantly from the previous record holder – also based on a NREL design. Instead of using a germanium wafer as the bottom junction of the device, the new design uses compositions of gallium indium phosphide and gallium indium arsenide to split the solar spectrum into three equal parts that are absorbed by each of the cell's three junctions for higher potential efficiencies. This is accomplished by growing the solar cell on a gallium arsenide wafer, flipping it over, then removing the wafer. The resulting device is extremely thin and light and represents a new class of solar cells with advantages in performance, design, operation and cost.

NREL's Mark Wanlass invented the original inverted cell, which recently won a R&D 100 award. His design was modified by a team led by John Geisz that further optimized the junction energies by making the middle junction metamorphic as well as the bottom junction. Metamorphic junctions are lattice mismatched – their atoms don't line up. The material properties of the mismatched semiconductors allows for greater potential conversion of sunlight.

http://www.sciencedaily.com/releases/2008/09/080929220900.htm

[kristopher]

1. Whoa there, not so fast...

University Of Delaware-led Team Sets Solar Cell Record

ScienceDaily (July 30, 2007) — Using a novel technology that adds multiple innovations to a very high-performance crystalline silicon solar cell platform, a consortium led by the University of Delaware has achieved a record-breaking combined solar cell efficiency of 42.8 percent from sunlight at standard terrestrial conditions.

That number is a significant advance from the current record of 40.7 percent announced in December and demonstrates an important milestone on the path to the 50 percent efficiency goal set by the Defense Advanced Research Projects Agency (DARPA). In November 2005, the UD-led consortium received approximately $13 million in funding for the initial phases of the DARPA Very High Efficiency Solar Cell (VHESC) program to develop affordable portable solar cell battery chargers.

Combined with the demonstrated efficiency performance of the very high efficiency solar cells' spectral splitting optics, which is more than 93 percent, these recent results put the pieces in place for a solar cell module with a net efficiency 30 percent greater than any previous module efficiency and twice the efficiency of state-of-the-art silicon solar cell modules.

As a result of the consortium's technical performance, DARPA is initiating the next phase of the program by funding the newly formed DuPont-University of Delaware VHESC Consortium to transition the lab-scale work to an engineering and manufacturing prototype model. This three-year effort could be worth as much as $100 million, including industry cost-share.

The ground-breaking research was led by Allen Barnett, principal investigator and UD professor of electrical and computer engineering, and Christiana Honsberg, co-principal investigator and associate professor of electrical and computer engineering. The two direct the University's High Performance Solar Power Program and will continue working to achieve 50 percent efficiency, a benchmark that when reached would mean a doubling of the efficiency of terrestrial solar cells based around a silicon platform within a 50-month span...

http://www.sciencedaily.com/releases/2007/07/070726210931.htm

[midnight]

2. 42.8 VS 40.8. Students VS Government. Students win?

University Of Delaware-led Team Sets Solar Cell Record

ScienceDaily (July 30, 2007) — Using a novel technology that adds multiple innovations to a very high-performance crystalline silicon solar cell platform, a consortium led by the University of has achieved a record-breaking combined solar cell efficiency of 42.8 percent from sunlight at standard terrestrial conditions.


VS.




ScienceDaily (Sep. 30, 2008) — Scientists at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have set a world record in solar cell efficiency with a photovoltaic device that converts 40.8 percent of the light that hits it into electricity. This is the highest confirmed efficiency of any photovoltaic device to date.