Cascade solar cells
A monolithic cascade cell for converting incident radiation, particularly solar radiation, into electrical energy at a high efficiency with at least three layers of semiconductive Group III-IV material is described. The top layer is doped into p and n regions with a homojunction therebetween and has a bandgap such that photons above a predetermined energy interact with the semi-conductive material to produce a potential across the homojunction and current flow and photons below that energy pass through the first layer to a second similar layer having a lower bandgap so that some of the radiation passing through the first layer produces a potential across a homojunction in the second layer to improve the overall energy conversion efficiency of the cell. The first and second layers are separated by at least a third layer of a Group III-V material, similarly doped into p and n regions with a tunnel junction formed therebetween to provide a low voltage electrical connection between the first and second layers. In one embodiment, the first and second layers are connected in series to be additive so that current flow takes place between contacts associated with the first and second layers. In another embodiment, the first and second layers are connected in opposition with a third terminal connected to the third layer which, in this case, need not be a tunnel junction. Alternatively, the two layers may be light producing devices such as light emitting diodes (LEDs), emitting light at different wavelengths, or photodiodes, detecting light of different wavelengths, or one layer can be a lightproducing device such as an LED while the other layer is a light receiving device such as a photodiode, again operating at different wavelengths. 25 claims.
- Assignee:
- Research Triangle Inst.
- Patent Number(s):
- US 4179702
- OSTI ID:
- 5600712
- Resource Relation:
- Patent File Date: Filed date 9 Mar 1978
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GALLIUM ARSENIDE SOLAR CELLS
GRADED BAND GAPS
GALLIUM PHOSPHIDE SOLAR CELLS
SOLAR CELLS
ALUMINIUM ARSENIDES
DESIGN
EFFICIENCY
ELECTRONIC CIRCUITS
ENERGY GAP
GALLIUM ARSENIDES
GALLIUM PHOSPHIDES
INDIUM ARSENIDES
INDIUM PHOSPHIDES
SPECTRAL RESPONSE
ALUMINIUM COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
DIRECT ENERGY CONVERTERS
EQUIPMENT
GALLIUM COMPOUNDS
INDIUM COMPOUNDS
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PNICTIDES
SOLAR EQUIPMENT
140501* - Solar Energy Conversion- Photovoltaic Conversion