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Advanced Photovoltaics
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Energy conversion from sunlight is a very promising route towards the increasingly pressing energy supply problem. The Sun is potentially able to take over any other type of renewable energy, even if this possibility is strongly limited by a number of issues, among which the inadequate conversion efficiency. | ||
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Today, the large cost per Watt peak (~ 5 €/Wp) of PV energy hinders an effective solution to the energy supply problem. To achieve a substantial cost reduction it is crucial to identify new approaches to the concept of solar energy conversion. | |
| Quantum nanostructures can increase the energy-conversion efficiency, under unconcentrated solar irradiance, from 31% (Shockley-Queisser limit for an optimized 1.3 eV bandgap material), up to the maximum attainable thermodynamic limit of 66%. The use of silicon quantum dots (QDs) and nanowires (NWs) could be efficiently exploited for increasing the conversion efficiency on a large-scale production. By using the quantum confinement effect, materials with tailored bandgap can be obtained, which absorb photons in a wider energy range. At the same time reduced thermalization is achieved, so increasing the probability of harvesting the full energy of absorbed sunlight. QD with low-bandgap within a larger bandgap material increases the photocurrent while, by tuning the QD size, higher bandgap materials can be obtained, which increases the photovoltage. The use of Si nanostrucutres in SiO2 is highly strategic for possible future large-scale integration of PV, and alternative matrixes for Si QD have been proposed such as Si nitrides or carbide, and amorphous Si. |  | |
| On the other hand, NWs provide new opportunities for addressing the cost and efficiency issues of PV. The potential advantages are manifold: the possibility of having large amounts of absorbing materials; the reduction of light reflection at the cell surface, especially in the high frequency region of the solar spectrum; the use of geometries which orthogonalize light absorption and carrier collection and the use in the so called excitonic solar cells either in all-inorganic or in hybrid devices, to make the distance between absorption location and collecting interface as small as possible. |
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PARTICIPANTS |
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| CRUPI Isodiana | 095 3785396 | |
| MIRABELLA Salvo | 095 3785510 | |
| PENNISI Agostino | 095 3785391 | |
| TERRASI Antonio | 095 3785431 | |