New Solar Cell Boasts High Efficiency, Lower Cost

Panasonic and SunPower have unveiled the specifications of a new technology that allows silicon solar cells to achieve record efficiency at a cost that they say is competitive with carbon-based fuels.

Until now, the record was held by a cell developed in Australia two decades ago. The new development is seen as significant progress for silicon solar cells, the most common devices on the market. The details were outlined recently at the Institute of Electrical and Electronics Engineers (IEEE) Photovoltaic Specialists Conference in Denver.

"Amazingly, the 20-year-old efficiency record was eclipsed at this conference by three companies, Panasonic, Sharp, and SunPower," says Richard Swanson, cofounder and former president of SunPower.

The new design combines technologies used in the most efficient designs of solar cells already on the market, which already are made by SunPower and Panasonic. The SunPower cells have improved efficiency because both positive and negative contacts are on the back of the cell, not on the front, which would block sunlight.

Panasonic adds a feature that provides more efficiency: It applies thin films of silicon to both sides of the crystalline silicon wafers in the cell to prevent imperfections at or near the wafers' surfaces from trapping electrons, which would decrease current and voltage.

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The new solar cell turns 25.6 percent of sunlight energy into electricity. This may seem like a small improvement in efficiency over the 25 percent achieved by the previous record holder, which was developed in Australia at the University of New South Wales.

But even this small edge can mean far greater power output from a large array of solar cells. More important, it demonstrates that the design adjustments to solar cells by both Panasonic and SunPower can lead to even greater improvement from future research.

Panasonic says the price for such panels are likely to be competitive with more conventional, carbon-based sources of electricity. Still, Martin Green, the Australian researcher who developed the previous record holder, says they will need high-quality - and high-cost - silicon crystals. Green's designs often use lower-cost silicon and, as a result, are being adopted by several manufacturers of solar cells.

By Andy Tully of Oilprice.com