NASA Scientific and Technical Aerospace Reports

20040120911 National Renewable Energy Lab., Golden, CO
Polycrystalline Thin Film Photovoltaics: Reseasrch, Development, and Technologies
Ullal, H. S.; Zweibel, K.; von Roedern, B.; May 2002; 14 pp.; In English
Report No.(s): DE2004-15007048; NREL/CP-520-32187; No Copyright; Avail: Department of Energy Information Bridge
II-VI binary thin-film solar cells based on cadmium telluride (CdTe) and I-III-VI ternary thin-film solar cells based on
copper indium diselenide (CIS) and related materials have been the subject of intense research and development in the past
few years. Substantial progress has been made thus far in the area of materials research, device fabrication, and technology
development, and numerous applications based on CdTe and CIS have been deployed worldwide. World record efficiency of
16.5% has been achieved by NREL scientists for a thin-film CdTe solar cell using a modified device structure. Also, NREL
scientists achieved world-record efficiency of 21.1% for a thin-film CIGS solar cell under a 14X concentration and AM1.5
global spectrum. When measured under a AM1.5 direct spectrum, the efficiency increases to 21.5%. Pathways for achieving
25% efficiency for tandem polycrystalline thin-film solar cells are elucidated. R&D issues relating to CdTe and CIS are
reported in this paper, such as contact stability and accelerated life testing in CdTe, and effects of moisture ingress in thin-film
CIS devices. Substantial technology development is currently under way, with various groups reporting power module
efficiencies in the range of 7. 0% to 12.1% and power output of 40.0 to 92.5 W. A number of lessons learned during the
scale-up activities of the technology development for fabrication of thin-film power modules are discussed. The major global
players actively involved in the technology development and commercialization efforts using both rigid and flexible power
modules are highlighted.
NTIS
Photovoltaic Cells; Thin Films; Solar Cells; Research and Development
20040120912 National Renewable Energy Lab., Golden, CO
DOE/NREL Fundamental and Exploratory Research into Solar Cells
Matson, R.; McConnell, R.; May 2002; 12 pp.; In English
Report No.(s): DE2004-15007046; NREL/CP-520-31484; No Copyright; Avail: Department of Energy Information Bridge
This conference paper describes the U.S. Department of Energy / National Renewable Energy Laboratory supports
fundamental and exploratory research into solar cells. The purpose of the following set of research projects is twofold: (1) to
provide fundamental experimental and theoretical foundations to existing photovoltaic (PV)/solar cell technologies, and (2)
to explore whole new possibilities in PV/solar cell technologies, however revolutionary or unconventional they might be. As
surely as a number of revolutionary new solar cell technologies will most likely involve high-risk, long-term R&D to bring
them to fruition, and may also well be needed as a complement to a future energy portfolio, so we also need timely results.
As such, one of the primary driving motives for this effort is the possibility of developing one or more ‘leapfrog’ technologies.
These are technologies that have the distinct possibility of ‘leaping ahead’ of existing technologies rather than taking the more
characteristic development time of 10 to 20 years.
NTIS
Research and Development; Solar Cells
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ENVIRONMENT POLLUTION
Includes atmospheric, water, soil, noise, and thermal pollution.
20040111149 Lawrence Livermore National Lab., Livermore, CA
Technical Basis Document No. 6: Waste Package and Drip Shield Corrosion
Farmer, J.; Pasupathi, V.; Nair, P.; Gordon, G.; McCright, D.; Aug. 01, 2003; In English
Report No.(s): DE2004-15005729; UCRL-LR-155288; No Copyright; Avail: National Technical Information Service (NTIS)
The waste package and drip shield will experience a wide range of interactive environmental conditions and degradation
modes that will determine the overall performance of the waste package and repository. The operable modes of degradation
are determined by the temperature regime of operation (region), and are summarized here. Dry-Out Region (T(ge) 120 C; 50
to 400 Years): During the pre-closure period, the waste package will be kept dry by ventilation air. During the thermal pulse,
heat generated by radioactive decay will eventually increase the temperature of the waste package, drip shield and drift wall
to a level above the boiling point, where the probability of seepage into drifts will become insignificant. Further heating will
push the waste package surface temperature above the deliquescence point of expected salt mixtures, thereby preventing the
formation of deliquescence brines from dust deposits and humid air. Phase and time-temperature-transformation diagrams
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