Potential-induced degradation in solar cells: Electronic structure and diffusion mechanism of sodium in stacking faults of silicon
| Autor: | Matous Mrovec, Christian Elsässer, Benedikt Ziebarth, Peter Gumbsch |
|---|---|
| Přispěvatelé: | Publica |
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Silicon
Solarzelle Band gap Diffusion Stapelfehler Stacking General Physics and Astronomy chemistry.chemical_element Electronic structure atomistische Simulation Potential induced degradation Silizium Dichte-Funktional-Theorie Natrium first-principles density-functional-theory chemistry Chemical physics Electrical resistivity and conductivity Density functional theory Atomic physics potential-induzierte Degradation |
| Popis: | Sodium decorated stacking faults (SFs) were recently identified as the primary cause of potential-induced degradation in silicon (Si) solar-cells due to local electrical short-circuiting of the p-n junctions. In the present study, we investigate these defects by first principles calculations based on density functional theory in order to elucidate their structural, thermodynamic, and electronic properties. Our calculations show that the presence of sodium (Na) atoms leads to a substantial elongation of the Si-Si bonds across the SF, and the coverage and continuity of the Na layer strongly affect the diffusion behavior of Na within the SF. An analysis of the electronic structure reveals that the presence of Na in the SF gives rise to partially occupied defect levels within the Si band gap that participate in electrical conduction along the SF. |
| Databáze: | OpenAIRE |
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