NASA SBIR 2004 Solicitation


PROPOSAL NUMBER: 04 E2.06-8384
SUBTOPIC TITLE: Energy Conversion for Space Applications
PROPOSAL TITLE: CuInGaAlSe2 solar absorbers on flexible high-temperature substrates

SMALL BUSINESS CONCERN (Name, E-mail, Mail Address, City/State/Zip, Phone)
ITN Energy Systems, Inc.
8130 Shaffer Parkway
Littleton, CO 80127-4107

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Dr. Lawrence Woods
8130 Shaffer Parkway
Littleton, CO 80127-4107

ITN Energy Systems (ITN) proposes to take the next step in spacecraft solar array development, building upon previous development and new findings to make the definitive light-absorber layer for high-power, lightweight and flexible thin-film photovoltaics (TFPV). ITN's innovative approach is to alloy CuInSe2 (CIS) with both aluminum and gallium bandgap widening elements in the chalcopyrite matrix to form CuInGaAlSe2 (CIGAS) for simultaneous optimization of the bandgap and material properties. Both Ga and Al will be used to take advantage of the alloy enhancing properties that each offers when used in moderation, while avoiding the detrimental issues when using too much of any one element to achieve the optimum bandgap of about 1.45 eV for a single-junction in the space solar spectrum. Furthermore, a recently available novel lightweight, flexible and transparent substrate will be used that was specifically designed to enable high-temperature CIGAS depositions as needed for the highest efficiency TFPV. TFPV specific power of over 1500 W/kg at the blanket/module level would be achievable The novel transparent substrates would also enable additional power from bifacial visible light collection and lower temperature operation, from improved infra-red (IR) transmission, in addition to enabling TFPV fabrication by low-cost roll-to-roll processing.

ITN's proposed technology, potentially decreasing the weight of spacecraft solar power by 75%, would have broad impact on NASA spacecraft weight and launch costs. NASA applications would also benefit from a wide-bandgap PV device, as proposed, for better thermal stability, better temperature coefficients, and higher-voltage solar arrays. Furthermore, the high specific power (W/kg) and ability of the proposed TFPV to be integrated into the balloon, high-altitude airship (HAA) or tent fabric, would enable balloon or HAA applications, in addition to modular and quick deploying tents for surface assets or lunar or Mars base power. The high specific power and power density would also enable Earth and Mars unmanned aerial vehicles (UAV) applications.

Two of the most important, near-term markets for high-efficiency flexible lightweight photovoltaics are spacecraft and aerostats/high-altitude airships (HAA). The target customers for this market are aerospace companies, defense, and communications industries. The largest market is in the evolving HAA industry, but there is also an opportunity in the well-established satellite community. Market projections indicate that approximately 16.5 MW of flexible thin film PV power will to be launched for HAA's, and 1.0 MW of space PV power will be launched between 2007 and 2011. In the long term, as the costs eventually come down with manufacturing process improvements and economies of scale, the PV space/HAA product technology can be leveraged for the implementation of the low-cost monolithic tandem PV terrestrial product. The terrestrial PV market is projected to be a $163 ? 302 M (min and max estimates) per year market by 2010 for thin-film technologies in North America alone, with a compound annual growth rate between 16.1% and 32.3%.