Light Weight, Low Cost, High Efficiency Solar Cells for Space Planar Arrays.
Abstract
The objective of the High Efficiency Solar Cell Program was to develop a cost effective, high efficiency solar cell that could be easily integrated into existing Air Force space systems to provide increased BOL and EOL efficiency. Gallium arsenide (GaAs) solar cells at 18% efficiency are state of the art; this program desired to increase the solar conversion efficiency of solar cells to >20%. Spectrolab, Inc. met this objective with a GalnP/GaAs/Ge triple junction solar cell structure, which successfully demonstrated AMO, 28 C efficiencies up to 23.3% for a 2x2 cm solar cell. The lot average efficiency of 75 cells delivered to the Air Force was 22.0%. The triple junction cell was developed in two parts, a GalnP/GaAs tandem cell and Ge bottom cell. At the end of the program, the top tandem cell was capable of contributing 22% to the overall cell efficiency and the Ge cell was capable of contributing 1.9%. The cells were extensively tested, including electron radiation, temperature coefficient, 30 day humidity tests, and thermal vacuum cycling to show that these cells were a viable direct replacement for GaAs cells and capable of operating in nominal space environments.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1997
- Accession Number
- ADB220921
Entities
People
- David Lillington
- Terry Cavicchi