Search results for " Solar"

Axion search with BabyIAXO in view of IAXO

2020

Axions are a natural consequence of the Peccei-Quinn mechanism, the most compelling solution to the strong-CP problem. Similar axion-like particles (ALPs) also appear in a number of possible extensions of the Standard Model, notably in string theories. Both axions and ALPs are very well motivated candidates for Dark Matter, and in addition, they would be copiously produced at the sun's core. A relevant effort during the last decade has been the CAST experiment at CERN, the most sensitive axion helioscope to-date. The International Axion Observatory (IAXO) is a large-scale 4th generation helioscope. As its primary physics goal, IAXO will look for solar axions or ALPs with a signal to backgro…

Short distance neutrino oscillations with Borexino

2014

International audience; The Borexino detector has convincingly shown its outstanding performances in the low energy, sub-MeV regime through its unprecedented accomplishments in the solar and geo-neutrinos detection. These performances make it the ideal tool to accomplish a state-of-the-art experiment able to test unambiguously the long-standing issue of the existence of a sterile neutrino, as suggested by the several anomalous results accumulated over the past two decades, i.e. the outputs of the LSND and Miniboone experiments, the results of the source calibration of the two Gallium solar neutrino experiments, and the recently hinted reactor anomaly. The SOX project will exploit two source…

Concrete thermal energy storage for linear Fresnel collectors: Exploiting the South Mediterranean’s solar potential for agri-food processes

2018

Abstract Italy is celebrated in the world for its agri-food industries while the process of production of pasta is highly energy demanding and requires both electrical and thermal energy simultaneously. Because most of the Italian factories producing pasta are located in the Southern part of the country, the direct use of thermal energy generated from the sun would be particularly profitable. In this study, the authors examine the possibility of generating by a Solar Industrial Process Heating plant the thermal energy required annually by an existing factory that produces durum wheat pasta located in Sicily (Italy). The hypothesized plant scheme consists of an array of Fresnel linear solar …

Unconventional materials for light-emitting and photovoltaic applications

2018

La motivación de este trabajo es el problema energético y éste ha sido abordado de dos maneras en esta tesis doctoral: promover un aumento de producción de energía mediante energías renovables junto con una reducción del consumo energético mediante el uso de sistemas más eficientes. Para este propósito, en esta tesis se han desarrollado dispositivos electroluminiscentes y fotovoltaicos novedosos de bajo coste y eficientes. En concreto, el trabajo se ha focalizado en el desarrollo de células electroquímicas emisoras de luz (LECs) emisoras en el rojo e infrarrojo cercano y en la mejora de su estabilidad. Así como en la fabricación de células solares de perovskita de alta eficiencia. Los dispo…

Semitransparent Perovskite Solar Cells with Multilayered Metal Top Electrodes for BIPVs and Tandem Applications

Semitransparent perovskite-based solar cells (ST-PSCs) are highly desired to be integrated into buildings as electricity-generating solar windows in the context of Building-Integrated Photovoltaics (BIPVs), as well as in tandem solar cells combined with other low-bandgap solar cells (e.g. silicon or CIGS) to give enhanced light-harvesting. To fabricate high-performance ST-PSCs, one key challenge is that of replacing the conventional opaque metal top electrodes with suitable transparent alternatives. Recently, dielectric/metal/dielectric (DMD) multilayer architectures have been shown to be suitable candidates as transparent top electrodes, exhibiting ideal characteristics such as mechanical …

Neutron star collapse and gravitational waves with a non-convex equation of state

2018

The thermodynamical properties of the equation of state (EoS) of high-density matter (above nuclear saturation density) and the possible existence of exotic states such as phase transitions from nuclear/hadronic matter into quark-gluon plasma, or the appearance of hyperons, may critically influence the stability and dynamics of compact relativistic stars. From a theoretical point of view, establishing the existence of those states requires the analysis of the `convexity' of the EoS. We show indications of the existence of regions in the dense-matter EoS where the thermodynamics may be non-convex as a result of a non-monotonic dependence of the sound speed with the rest-mass density. When th…

Spatial inhomogeneities and defect structures in CIGS and CIS materials: An ab-initio based Monte Carlo study

2011

The chalcopyrite semiconductors CuIn 1−x Ga x Se 2 (CIGS) and CuInSe 2 (CIS) are excellent materials for high efficiency and low cost thin-film solar cells. This is due to the effective absorption of the solar spectrum and the inherent resilience to defects and composition fluctuations. Although the CIGS and CIS material in solar cells is highly inhomogeneous and exhibits a lot of different defects, the cell efficiencies are exceptionally high. If single crystalline absorbers are used, efficiencies are lower. Therefore, studying spatial inhomogeneities and defect structures is of great importance for understanding what supports and what diminishes the efficiency and robustness of the cells.…

Trilateral π-conjugation extensions of phenothiazine-based dyes enhance the photovoltaic performance of the dye-sensitized solar cells

2016

Abstract Two novel organic dyes TLEP-1 and TLEP-2 based on phenothiazine with trilateral π-conjugation extensions were designed and synthesized for dye-sensitized solar cells, where phenothiazine ring was linked with two phenyl moieties at 7- and 10-positions as the first and second π-conjugation extensions, and with furan or thiophene ring at 3-position as the third π-conjugation extension for TLEP-1 and TLEP-2, respectively. The influence of the π-conjugation extensions on the photovoltaic performance was evaluated. The cell based on TLEP-2 exhibits an impressive short-circuit photocurrent density of 14.87 mA cm−2, which is much higher than the cell based on the reference dye without π-co…

Conjugating pillararene dye in dye-sensitized solar cells

2021

Summary The improvement of open-circuit voltage (VOC) is a crucial goal to develop efficient dye-sensitized solar cells (DSSCs). Here, conjugating pillar[5]arene dyes (PPI and PPII) are designed, synthesized, and applied in DSSCs. The presence of pillar[5]arene moiety in the dyes inhibits the dye aggregation and charge recombination in the DSSCs, leading to the enhancement of VOC. PPI with a single D-π-A backbone and a pillar[5]arene moiety achieves a VOC of 715 mV, which is much higher than the reference dye (VOC of 674 mV) with the same D-π-A backbone but no pillar[5]arene moiety. PPII with 2 D-π-A backbones also achieves a VOC of 746 mV and a much higher short-circuit photocurrent (JSC) …

Impact of π-conjugation configurations on the photovoltaic performance of the quinoxaline-based organic dyes

2017

Abstract Three novel quinoxaline-based donor-π-acceptor type organic dyes were synthesized and explored as sensitizers in dye-sensitized solar cells (DSSCs). The impacts of various π-conjugation configurations which contain different quinoxaline derivatives on the absorption properties, electrochemical properties and photovoltaic performances, as well as theoretical calculations have been investigated systematically. The photovoltaic performances of these dyes were found to be highly relevant to the π-conjugated configurations. In particular, the DSSC based on the dye with 2,3-dioctylquinoxaline as the spacer exhibited the highest efficiency of 8.20% with a short-circuit photocurrent densit…