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20 March 2008


RoseStreet opens full-spectrum solar cell development center

RoseStreet Labs Energy Inc of Phoenix, AZ, USA has formally opened its new solar cell development center, which includes a full-spectrum photovoltaic pilot line as well as a laboratory for solar cell packaging and interconnection.

The firm is a 50:50 joint venture formed in October 2006 between RoseStreet Labs LLC and Sumitomo Chemical Co Ltd of Tokyo, Japan with start-up capital of $6.6m to develop both thin-film and multi-junction high-efficiency solar cells for both the concentrated photovoltaic (CPV) and flat-panel markets. After R&D and product development during 2007, last August the firm announced p lans to install the pilot line, which should enable the firm to field test prototypes this year in terrestrial CPV distributed energy, flat panel, space and architectural applications.

RoseStreet Labs Energy collaborates locally on packaging with FlipChip International LLC (a subsidiary of RoseStreet Labs LLC that supplies products and services for wafer bumping and wafer-scale packaging). In addition, Sumika Electronic Materials Inc (a subsidiary of Sumitomo Chemical that is also based in Phoenix and specializes in epitaxial processes and services) will continue to provide support for manufacturing and development.

“The innovative RoseStreet Energy approach to utilization of solar energy is based on recent research breakthroughs at major scientific institutions,” says chief technical officer Dr Wladek Walukiewicz. “The research advances allowed for realization of new concepts of high-efficiency solar cells,” he claims.

In 2005 RoseStreet Labs agreed exclusive patent licenses with both the US Department of Energy’s Lawrence Berkeley National Laboratory (LBNL) as well as Cornell University for devices that use a significantly larger fraction of the solar spectrum compared to existing products.

Consequently, the firm is commercializing LBNL’s multi-band technology (developed by Walukiewicz and Kin Man Yu at LBNL), which uses oxygen impurities to split the conduction band of zinc manganese tellurium (ZnMnTe). This enables devices to achieve the efficiencies of a triple-junction device with the manufacturing cost and simplicity of a single-junction device, it is claimed (more than 50% for triple-band material, in theory).

RoseStreet Energy is also commercializing the InGaN multi-junction technology of LBNL and Cornell, which should provide the thermal and radiation properties necessary for next-generation CPVs used in distributed energy power generation. Practical efficiencies of more than 48% in both single-junction and multi-junction devices are potentially achievable, it is claimed.

“Our objective is to develop the high-performance solar cells at prices competitive with current commercial technologies,” says Walukiewicz. “Our progress during our first year has been substantial and our momentum is building for the launch of both our thin-film multi-band and multi-junction high-efficiency solar cells,” adds RoseStreet Labs Energy’s chairman Bob Forcier. “Customer interest has been exceptionally strong for our future product lines on an international basis,” he adds.

See related item:

RoseStreet Labs establishes JV with Sumitomo Chemical

Search: Solar cell Photovoltaic CPV InGaN