Automated array assembly task. Development of low-cost polysilicon solar cells. Quarterly technical report No. 1
Wacker material was the only polysilicon material considered during this reporting period, due to late delivery of other materials types. A batch of 10.1% efficient Wacker polysilicon solar cells were produced using the baseline fabrication sequence with standard POC1/sub 3/ gettering, spray-on-dopant junction formation and SiO AR coating. The highest efficiency obtained from this batch as 10.5%. The average crystal grain size for a sample lot of Wacker polysilicon wafers was found to be 0.16 inches. This result was employed to show that insufficient gridline coverage of polysilicon crystal grains can lead to a significant power loss. A theoretical and experimental comparison between single crystal and polysilicon solar cell efficiencies was used to investigate the impact of the structural properties of polysilicon material on solar cell efficiency. The experimental data obtained in this study are in agreement with the theoretical predictions of the diffusion length model of polysilicon material. On the basis of this correlation, it was concluded that the lower efficiencies of polysilicon solar cells made from Wacker polysilicon material, relative to single crystal silicon olar cells, are not due to processing inadequacies, but rather to grain boundary effects.
- Research Organization:
- Sensor Technology, Inc., Chatsworth, CA (USA)
- DOE Contract Number:
- NAS-7-100-955265
- OSTI ID:
- 5568375
- Report Number(s):
- DOE/JPL/955265-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SILICON SOLAR CELLS
EFFICIENCY
FABRICATION
DIFFUSION
GETTERING
GRAIN BOUNDARIES
GRAIN SIZE
POLYCRYSTALS
PROCESSING
SEMICONDUCTOR JUNCTIONS
SPRAY COATING
CRYSTAL STRUCTURE
CRYSTALS
DEPOSITION
DIRECT ENERGY CONVERTERS
EQUIPMENT
JUNCTIONS
MICROSTRUCTURE
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SIZE
SOLAR CELLS
SOLAR EQUIPMENT
SURFACE COATING
140501* - Solar Energy Conversion- Photovoltaic Conversion