Review and Understanding of Screen-Printed Contacts and Selective-Emitter Formation: Preprint
A comparison of the loss mechanisms in screen-printed solar cells relative to buried contact cells and cells with photolithography-defined contacts is presented in this paper. Model calculations show that emitter recombination accounts for about 0.5% absolute efficiency loss in conventional screen-printed cells with low-sheet-resistance emitters. Ohmic contact to high-sheet-resistance emitters by screen-printing has been investigated to regain this efficiency loss. Our work shows that good quality ohmic contacts to high sheet-resistance emitters can be achieved if the glass frit chemistry and Ag particle size are carefully tailored. The melting characteristics of the glass frit determine the firing scheme suitable for low contact resistance and high fill factors. In addition, small to regular Ag particles were found to help achieve a higher open-circuit voltage and maintain a low contact resistance. This work has resulted in cells with high fill factors (0.782) on high sheet-resistance emitters and efficiencies of 17.4% on planar float zone Si substrates, without the need for a selective emitter.
- Research Organization:
- National Renewable Energy Lab., Golden, CO (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC36-99-GO10337
- OSTI ID:
- 15009892
- Report Number(s):
- NREL/CP-520-36747; TRN: US200430%%1575
- Resource Relation:
- Conference: Prepared for the 14th Workshop on Crystalline Silicon Solar Cells and Modules, Winter Park, CO (US), 08/08/2004--08/11/2004; Other Information: PBD: 1 Aug 2004
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
CHEMISTRY
EFFICIENCY
FILL FACTORS
GLASS
MELTING
PARTICLE SIZE
RECOMBINATION
SCREEN PRINTING
SILICON SOLAR CELLS
SOLAR CELLS
SUBSTRATES
CRYSTAL GROWTH
PASSIVATION
MICROELECTRONICS
SOLAR ENERGY
PV
PHOTOVOLTAICS
CRYSTALLINE SILICON
MATERIALS AND PROCESSES
MODULE
IMPURITIES
DEVICE PROCESS
DEFECT
SOLAR ENERGY - PHOTOVOLTAICS