Beyond geometrical shadow factors with nanostructured contats for solar cells

Autor: Pérez de San Román, Etor, Vitrey, Alan, García-Martín, Antonio, Buencuerpo, Jerónimo, Llorens Montolio, José Manuel, Dotor, María Luisa, Ripalda, José María
Rok vydání: 2013
Zdroj: Digital.CSIC. Repositorio Institucional del CSIC
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Popis: Comunicación presentada en la 28th European Photovoltaic Solar Energy Conference and Exhibition (28th EU PVSEC), celebrada en Villepinte (Francia) del 30 de septiembre al 4 de octubre de 2013.
High Concentration PhotoVoltaics (HCPV) solar cells waste about 3% of incoming light (representing about 1% of absolute efficiency) due to absorption and reflection on the top contact metallization grid. Additionally, there is a loss of efficiency of about 1% due to the voltage loss caused by the series resistance at very high concentrations. Both losses are related to the top contact metallization grid as series resistance is in large part due to emitter resistance (related to the spacing in between metallization lines) and grid resistance (related to metal thickness). Halving both the series resistance and the shadow factor of the top contact would boost efficiency by 1% in absolute terms. In this work we show that contact metal lines with sub-wavelength widths have an effective shadow factor that is not the geometrical shadow factor but larger or smaller depending on light wavelength, polarization, contact geometry and material properties. Integrating over the spectral range of interest, a significantly increased transmission into the solar cell is obtained. These results are of great potential to improve solar cell efficiencies and their economical viability, especially in the case of concent rator multijunction tandem solar cells, as the costs of nano-fabrication are divided by the concentration factor (typically around 500).
Databáze: OpenAIRE