30% efficient three junction solar cells for space concentrator modules. Final report 1 September 1997-31 May 1998

Technical Report · Wed Jul 15 04:00:00 EDT 1998

OSTI ID:658754

Fraas, L M; Avery, J E

The benefits of mechanically stacked tandem concentrator solar cells were first demonstrated on a NASA mission in 1994. In that case, transparent GaAs cells were stacked on top of infrared-sensitive GaSb booster cells and arrayed in a point-focus solar concentrator module. The results were high efficiency, excellent radiation resistance and high voltage tolerance, all of which sustained some interest in concentrator arrays. Since then, the lens design has evolved to a linear geometry used with high efficiency nontransparent GaInP{sub 2}/GaAs cells on germanium substrates. These high bandgap dual junction cells still leave about 35% of the sun`s longer wavelength energy uncollected. The proposal for this contract was to make the dual junction cell transparent to that long wavelength range and stack it on a GaSb booster cell for added efficiency gains. Tecstar made the transparent dual junction GaInP{sub 2}/GaAs cells on GaAs substrates as a subcontractor, and JX Crystals took on the tasks of booster cell fabrication as well as assembly and testing for this Phase 1 effort. Resulting dual junction cells achieved efficiencies of 29.6% at a 15 sun concentration level.

• Research Organization: JX Crystals, Inc., Issaquah, WA (United States)
• OSTI ID: 658754
• Report Number(s): AD-A--349685/XAB; BMDO--97-FNL; CNN: Contract NAS3-97180
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
CONCENTRATOR SOLAR CELLS
DESIGN
GALLIUM ARSENIDE SOLAR CELLS
PERFORMANCE
SOLAR CELL ARRAYS
SPACECRAFT POWER SUPPLIES