New Approach to Silicon Aims to Slash Cost of Solar Cells

Prices for solar-generated electricity could soon approach those of power from coal or natural gas thanks to collaborative research between solar start-up. Ampulse Corporation and the US Department of Energy's National Renewable Energy Laboratory (NREL). They have teamed to create a less-expensive alternative to wafer-based crystalline silicon solar cells. By using a chemical vapor deposition process to grow the silicon on inexpensive foil, Ampulse is able to make the solar cells just thick enough to convert most of the solar energy into electricity. No more wasting refined silicon materials in the form of sawdust.

Current crystalline silicon technology, while high in energy conversion efficiency, involves processes that are complex, wasteful, and energy intensive. First, half the refined silicon is lost as dust in the wafer-sawing process, driving module costs higher. A typical 2-m boule of silicon loses as many as 6000 potential wafers during sawing. Second, the wafers produced are much thicker than necessary. To efficiently convert sunlight into electricity, they need only one-tenth the typical thickness. 

NREL, DOE's Oak Ridge National Laboratory (ORNL), and Ampulse have teamed on an approach to eliminate this waste of material. Chemical vapor deposition allows silicon to grow on inexpensive foil.

NREL developed the technology to grow high-quality silicon. ORNL developed the metal foil that has the correct crystal structure to support that growth. Ampulse is installing a pilot manufacturing line in NREL's Process Development Integration Laboratory (PDIL), where solar companies can work closely with NREL scientists on integrated equipment to answer pressing questions related to their technology development, as well as rapidly overcoming R&D challenges and risk. The PDIL program is focused on transformative innovation in the domestic PV industry.

With knowledge and expertise acquired from the PDIL pilot production-line tools, Ampulse plans to design a full-scale production line to accommodate long rolls of metal foil. The Ampulse process goes straight from pure silicon-containing gas to high-quality crystal silicon film, therefore, a wafer can be made as thin as needed.

Recently, with its SunShot Initiative, DOE challenged researchers to lower the cost of solar energy by two-thirds to $1 per watt installed. This goal necessitates disruptive innovation, which is just what Ampulse is doing, said Martha Symko-Davies, Solar Business Manager for  PDIL.

Source:

NREL News