Poly- vs single-crystal silicon solar cells
Abstract
Purpose of these experiments was to identify effects of non-single crystalline structure on silicon solar cell performance. Pulled crystal (111) low-life-time, low-cost scrap ingot ends were used, of which about half of each was single, the other large-grained poly or twinned. Thus poly and single crystal cells could be cut from the same ingot and processed together for comparison. Annealing improved poly cell efficiency even though the electron diffusion length (10-40 microns) is less than the grain size 100-1000 microns. This suggests that principal effect of boundaries is to precipitate impurities. Electron diffusion length and short circuit current were highest in annealed twinned and columnar-grained poly. The open circuit voltage and fill-factor were highest in single because of their more perfect pn junctions. However, all these cells after anneal, except transverse-grained poly, had similar efficiency exceeding 9% AMI/AR-coated.
- Publication:
-
13th Photovoltaic Specialists Conference
- Pub Date:
- 1978
- Bibcode:
- 1978pvsp.conf.1090K
- Keywords:
-
- Polycrystals;
- Silicon;
- Single Crystals;
- Solar Cells;
- Annealing;
- Clean Energy;
- Energy Technology;
- Grain Boundaries;
- P-N Junctions;
- Energy Production and Conversion