Development of high-efficiency-cascade solar cells. Technical progress report No. 5, July 1, 1981-December 31, 1981
The present experimental work is focusing principally on the GaAlAsSb/GaAsSb cascade cell, which is of particular interest since it offers the optimum bandgap combination of 1.8/1.2 eV for maximum efficiency in high temperature concentrator applications. The major problem experienced thus far in the development of the AlGaAsSb/GaAsSb cell has been the relatively low open circuit voltages (V/sub oc/) that have been characteristic of both top and bottom cell junctions. Addressing this problem continues to be a major objective of the continued development of this cell. The AlGaAs/GaAs cell is being retained as a backup to the antimonide cell. Although the AlGaAs/GaAs cell is not capable of achieving the optimum 1.8/1.2 eV bandgap combination, it avoids problems associated with lattice mismatch with the GaAs substrate and offers a more proven materials technology. Computer analysis of this cell shows that a 1.92/1.43 eV bandgap combination is capable of achieving an active area efficiency of about 27% at Am1.5, 300/sup 0/K, 1 sun. At 500 suns this cell is predicted to have efficiency values of about 30% at 300/sup 0/K and 20% at 475/sup 0/K. Experimental AlGaAs/GaAs cells without AR coatings have exhibited measured efficiency values of about 16% at AM1.5, 1 sun. This development effort has been focusing on performance improvement through improved tunnel junction performance, better ohmic contacts, and an optimized AR coating and on fabricating larger area cells.
- Research Organization:
- Solar Energy Research Inst., Golden, CO (USA); Research Triangle Inst., Research Triangle Park, NC (USA)
- DOE Contract Number:
- AC02-77CH00178
- OSTI ID:
- 5357547
- Report Number(s):
- SERI/PR-8136-1-T12; ON: DE82014517
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
ALUMINIUM ARSENIDES
ALUMINIUM COMPOUNDS
ANTIMONY COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
CASCADE SOLAR CELLS
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
COMPUTERIZED SIMULATION
CONCENTRATOR SOLAR CELLS
CRYSTAL STRUCTURE
CURRENTS
DEPOSITION
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRIC CURRENTS
ELECTRIC POTENTIAL
EQUIPMENT
FABRICATION
GALLIUM ANTIMONIDES
GALLIUM ARSENIDE SOLAR CELLS
GALLIUM COMPOUNDS
GRADED BAND GAPS
JUNCTIONS
MICROSTRUCTURE
OPTIMIZATION
P-N JUNCTIONS
PERFORMANCE
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PNICTIDES
SEMICONDUCTOR JUNCTIONS
SIMULATION
SOLAR CELLS
SOLAR EQUIPMENT
SURFACE COATING
TEMPERATURE DEPENDENCE
TUNNEL EFFECT