Descripción
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We introduce one trivial but puzzling solar cell structure. It consists of a high bandgap pn junction (top cell) grown on a substrate of lower bandgap. Let us assume, for example, that the bandgap of the top cell is 1.85 eV (Al 0.3Ga 0.7As) and the bandgap of the substrate is 1.42 eV (GaAs). Is the open-circuit of the top cell limited to 1.42 V or to 1.85 V? If the answer is ldquo1.85 Vrdquo we could then make the mind experiment in which we illuminate the cell with 1.5 eV photons (notice these photons would only be absorbed in the substrate). If we admit that these photons can generate photocurrent, then because we have also admitted that the voltage is limited to 1.85 V, it might be possible that the electron-hole pairs generated by these photons were extracted at 1.6 V for example. However, if we do so, the principles of thermodynamics could be violated because we would be extracting more energy from the photon than the energy it initially had. How can we then solve this puzzle? | |
Internacional
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Si |
Nombre congreso
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39th IEEE Photovoltaic Specialists Conference |
Tipo de participación
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960 |
Lugar del congreso
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Tampa, FL, USA |
Revisores
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Si |
ISBN o ISSN
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978-1-4799-3299-3 |
DOI
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Fecha inicio congreso
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16/06/2013 |
Fecha fin congreso
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21/06/2013 |
Desde la página
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1069 |
Hasta la página
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1073 |
Título de las actas
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Proceedings 39th IEEE PVSC |