Impact of metal contamination in silicon solar cells
| Autor: | Paula C. P. Bronsveld, Gianluca Coletti, Bruno Ceccaroli, K. Wambach, Daniel Macdonald, Nam Le Quang, Juan M. Fernandez, Wilhelm Warta, Giso Hahn |
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| Přispěvatelé: | Publica |
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Materials science
Silicon Herstellung und Analyse von hocheffizienten Solarzellen chemistry.chemical_element impurities law.invention Biomaterials Chromium Impurity law Solar cell Electrochemistry ddc:530 Wafer Charakterisierung Ingot feedstock contaminations Solarzellen - Entwicklung und Charakterisierung Metallurgy silicon Condensed Matter Physics Electronic Optical and Magnetic Materials Silicium-Photovoltaik Nickel chemistry solar cells Condensed Matter::Strongly Correlated Electrons Zellen und Module Charakterisierung von Prozess- und Silicium-Materialien Titanium |
| Popis: | Summary The impact on solar cell performance of transition metals like iron, chromium, nickel, titanium and co pper is the topic of this extended abstract. Each impurity has been intentionally added to silicon feedstock used to gr ow p-type directionally solidified multicrystalline silicon i ngots. A state of the art screen print solar cell process ha s been applied to wafers cut from the bottom to the top of these ingots. Adding 50 ppmwt of iron or 40 ppmwt of nickel or chromium to silicon feedstock, results in comparabl e solar cell performances to reference uncontaminated material in the range 40% to 70% of the ingot height. Addition of 10 ppmwt of titanium dramatically reduces the efficien cy along the entire ingot. Impurities like iron, chromium an d titanium cause a reduction in the diffusion length. Nickel d oes not reduce the diffusion length. On the other hand affe cts strongly the emitter recombination reducing the sol ar cell performance significantly. Copper has the peculiari ty to impact both bulk recombination as well as emitter recombination. A model based on Scheil distribution of impurity ha s been derived to fit the degradation along the ingot. So lar cell performance has been modeled as function of base bulk recombination and emitter recombination. The model fits very well the experimental data and has been also successfully validated. Unexpectedly, the Scheil di stribution of impurity along the ingot leaves its finger-print also at the end of the solar cell process. A measure of impurit y impact has been defined as the level of impurity which cau ses a degradation of less than 2% up to 90% of the ingot height. The advantage of this parameter is that comprises t he different impurities physical characters in one sin gle parameter, easy to compare. |
| Databáze: | OpenAIRE |
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