Search results for "photovoltaicS"
showing 10 items of 178 documents
Plasmonic nanostructures for light trapping in photovoltaic
Metallic nanoparticles (NPs), sustaining localized surface plasmon resonances, are currently of great interest for enhancing light trapping in thin film solar cells. To be directly applicable in the photovoltaic industry, the NPs fabrication needs to be simple, reliable, low-cost and scalable. As such, self-assembly processes are most commonly used, and Ag is the preferred material, due to its high radiative efficiency and low imaginary permittivity. After exploring the correlation between structural and optical properties of Ag NPs fabricated by solid- state dewetting process on various substrates, we identified the fabrication conditions in which desirable NPs are obtained, but we also e…
Outdoor performance of north-facing multicrystalline modules in Southern Norway
2012
The present paper deals with reports on an outdoor performance evaluation of multicrystalline modules facing north in Southern Norway. The relevance of this study is mainly for building integrated systems where some of the facades are in a far from optimum position. The impact of shading on the photovoltaic modules' performance is also evaluated. A dedicated experimental set up has been created to study the PV modules performance under the above mentioned conditions. The results indicate significant power extraction from the PV modules even in the north facing direction. Effects of shadowing are also considered.
Hovering solar cells
2015
Ultrathin, flexible and lightweight perovskite solar cells with improved stability in air can now power model airplanes for several hours.
Size dependent light absorption modulation and enhanced carrier transport in germanium quantum dots devices
2015
Quantum confinement in closely packed arrays of Ge quantum dots (QDs) was studied for energy applications. In this work, we report an efficient tuning mechanism of the light harvesting and detection of Ge QDs. Thin films of SiGeO alloys, produced by rf-magnetron sputtering, were annealed at 600 degrees C in N-2 to induce precipitation of small amorphous Ge QDs into the oxide matrix. Varying the Ge content, the QD size was tailored between 2 and 4 nm, as measured by high resolution transmission electron microscopy. X-ray photoelectron spectroscopy (XPS) measurements indicate the formation of pure SiO2, as well as the presence of a sub-stoichiometric Ge oxide shell at the QD interface. Light …
Applying Dynamic Performance Management to the Photovoltaic Sector: the Municipality of Palermo case study
Today, the even more compelling need to limit carbon dioxide emissions from energy generation – to address the ongoing global warming – implies the recourse to renewable energy sources (RESs). Indeed, these latter are able to meet energy demand into a more sustainable way. Considering the EU targets for the year 2020 in the matter of climate and energy, public organizations are expected to take an active role e.g. by adopting and promoting RESs. In Italy, over the last decade, among the various technologies based on RESs, solar PV technology witnessed a remarkable growth thanks to the support of a government incentive scheme, which ceased to be applied in 2013. Since then, the PV power inst…
Critical assessment of support for the evolution of photovoltaics and feed-in tariff(s) in Italy
2015
Abstract The feed-in tariff(s) mechanism involves an obligation on the part of an electricity provider to purchase electricity generated by renewable energy sources in its relevant area, paying a tariff determined by public authorities and guaranteed for a specific time period. Feed-in tariff(s) have been the primary mechanism used for supporting the development of renewable energy sources in the EU and, up to date, they are being applied in 20 EU Member Countries. On 6 July 2013, the Italian experience with feed-in tariff(s) for photovoltaic systems finished. During its lifetime of eight years, this incentive mechanism, named “Conto Energia”, was characterized by periods of great success f…
Fast determination of impurities in metallurgical grade silicon for photovoltaics by instrumental neutron activation analysis
2010
Standard wafer solar cells are made of near-semiconductor quality silicon. This high quality material makes up a significant part of the total costs of a solar module. Therefore, new concepts with less expensive so called solar grade silicon directly based on physiochemically upgraded metallurgical grade silicon are investigated. Metallurgical grade silicon contains large amounts of impurities, mainly transition metals like Fe, Cr, Mn, and Co, which degrade the minority carrier lifetime and thus the solar cell efficiency. A major reduction of the transition metal content occurs during the unidirectional crystallization due to the low segregation coefficient between the solid and liquid phas…
Energie rinnovabili e trasformazioni territoriali: il caso del fotovoltaico in Sicilia
2021
La presente comunicazione intende trattare il tema delle trasformazioni territoriali sono avvenute negli ultimi due decenni in Sicilia, in seguito alla costruzione di centinaia di impianti fotovoltaici di piccole, medie e grandi dimensioni. Tali impianti sono stati costruiti causando spesso profondi mutamenti paesaggio, con trasformazioni territoriali che non hanno tenuto conto delle caratteristiche di produttività dei suoli, della vicinanza di aree protette e siti della Rete Natura 2000 e soprattutto senza il reale coinvolgimento delle comunità locali che spesso hanno subito passivamente tali trasformazioni. Gli strumenti di pianificazione territoriale, quali il Piano Paesistico Regionale,…
Light absorption in silicon quantum dots embedded in silica
2009
The photon absorption in Si quantum dots (QDs) embedded in SiO2 has been systematically investigated by varying several parameters of the QD synthesis. Plasma-enhanced chemical vapor deposition (PECVD) or magnetron cosputtering (MS) have been used to deposit, upon quartz substrates, single layer, or multilayer structures of Si-rich- SiO2 (SRO) with different Si content (43-46 at. %). SRO samples have been annealed for 1 h in the 450-1250 °C range and characterized by optical absorption measurements, photoluminescence analysis, Rutherford backscattering spectrometry and x-ray Photoelectron Spectroscopy. After annealing up to 900 °C SRO films grown by MS show a higher absorption coefficient a…