High-efficiency silicon concentrator solar cells for use with prismatic covers
- Astrosystems, Inc., Newark, DE (USA). Astropower Div.
Advanced-design 20X concentration silicon solar cells that are compatible with prismatic covers have been designed and fabricated. Our design is based upon a micro-machined, deeply grooved, three- dimensional silicon structure and incorporates a dual-layer emitter, oxide surface passivation layers for front and rear surfaces, and back surface reflector light-trapping technologies. Using solar grade'' Czochralski-grown silicon with a resistivity of 1.25 ohm-cm, we obtained open-circuit voltages as high as 679 mV and active-area current densities of up to 38.4 mA/cm{sup 2}. The best efficiency for a full-sized (50 cm{sup 2}) solar cell with prismatic cover is 17.8%. The performance of these devices is limited primarily by series resistance in the emitter and emitter contact due to the wide grid finger spacing (504 microns) and reflection from a groove ridgetop between the fingers. Increasing the density of front-contact fingers to eliminate the center ridge, together with a matched prismatic cover, will yield significant improvements in fill-factor and short-circuit current. Preliminary modeling of this design using PC-1D/2 indicates that efficiencies of up to 24% are feasible. With optimization of the fabrication sequence, the conversion efficiency of the deeply grooved concentrator solar cell should approach this level of performance.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Astrosystems, Inc., Newark, DE (USA). Astropower Div.
- Sponsoring Organization:
- DOE/CE
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5434568
- Report Number(s):
- SAND-89-7039; ON: DE90002644
- Country of Publication:
- United States
- Language:
- English
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