Search results for "Solar cell efficiency"
showing 10 items of 16 documents
Plasmonic and diffractive nanostructures for light trapping—an experimental comparison
2015
Metal nanoparticles and diffractive nanostructures are widely studied for enhancing light trapping efficiency in thin-film solar cells. Both have achieved high performance enhancements, but there are very few direct comparisons between the two. Also, it is difficult to accurately determine the parasitic absorption of metal nanoparticles. Here, we assess the light trapping efficiencies of both approaches in an identical absorber configuration. We use a 240 nm thick amorphous silicon slab as the absorber layer and either a quasi-random supercell diffractive nanostructure or a layer of self-assembled metal nanoparticles for light trapping. Both the plasmonic and diffractive structures strongly…
Higher PV Module Efficiency by a Novel CBS Bypass
2011
There is an increasing focus on reducing costs and improving efficiency for photovoltaic (PV) cells and modules as well as finding a more efficient approach to the product manufacturing. This letter introduces an innovative solution to bypass shaded PV cells instead of a traditional Schottky diode, in order to avoid overheating of cells in the case of partial shading. The goal is to reduce the power dissipation and improve the general efficiency of a PV generator. A novel device called cool bypass switch is then presented. It is made up of a Power MOS driven by a controller with the task to charge a storage capacitor. Tests and comparisons with standard Schottky diodes are then performed an…
3D photonic crystal intermediate reflectors for enhanced light-trapping in tandem solar cells
2012
The concept of 3D photonic crystals embedded in tandem solar cells as intermediate reflective layers is investigated. Numerical as well as experimental results will be presented.
Photoconductivity and optical properties of silicon coated by thin TiO2 film in situ doped by Au nanoparticles
2013
Light trapping enhancement by plasmonic-active metal nanoparticles (NPs) is believed to be a promising approach to increase silicon-based solar cell efficiency. Therefore, we investigated TiO2 films in situ doped by Au NPs (TiO2:AuNPs) deposited by spin coating on a silicon substrate. Photoconductivity and optical properties of the TiO2:AuNPs/Si structures were studied in comparison with those of TiO2/Si reference samples. We found that an introduction of the 40–50 nm diameter AuNPs into the antireflective TiO2 layer deteriorates the antireflection properties and decreases the external yield of photogeneration of charge carriers. This is due to an increase of the layer reflection in the red…
Combined heat and power generation with a HCPV system at 2000 suns
2015
In the framework of the FAE “Fotovoltaico ad Alta Efficienza” (“High Efficiency Photovoltaic”) Research Project funded by the Sicilian Region under the program PO FESR Sicilia 2007/2013 4.1.1.1, we have developed an innovative solar CHP system for the combined production of heat and power at the high concentration level of 2000 suns [1]. This work shows the experimental results obtained on FAE-HCPV modules and analyses the behaviour of the system. The solar radiation is concentrated on commercial InGaP/InGaAs/Ge triple-junction solar cells designed for intensive work. The primary optics is a rectangular off-axis parabolic mirror (with a size of 46x46 = 2116 cm2 in a projection normal to the…
Irradiance Dependent Temperature Coefficients for MC Solar Cells from Elkem Solar Grade Silicon in Comparison with Reference Polysilicon
2014
Abstract An increase in sun intensity enhances the output power of the solar cells, but at the same time the rise of cell temperature affects its electrical performance negatively. The present authors have made a comparative study on temperature coefficients at various irradiances of multicrystalline solar cells made from the standard Siemens process and from material produced by a metallurgical route – the Elkem Solar Silicon (ESS®) process. Such temperature coefficients measured while exposed to various irradiance levels are essential to build a better understanding and prediction of field performance of solar cells manufactured from various feedstock types. In the current experiment, the…
Photocurrent enhancement in thin a-Si:H solar cells via plasmonic light trapping
2014
Photocurrent enhancement in thin a-Si:H solar cells due to the plasmonic light trapping is investigated, and correlated with the morphology and the optical properties of the selfassembled silver nanoparticles incorporated in the cells' back reflector. © 2014 OSA.
Plasmon-induced slow aging of exciton generation and dissociation for stable organic solar cells
2016
Fast degradation is a major issue with organic photovoltaics (OPVs). Integrating plasmonics with OPVs has improved their efficiency; however, the stability effects are unknown. We demonstrate that plasmonic effects can improve the lifetime and efficiency. The aging effects on charge carrier generation and transport are investigated. Confocal time-resolved photoluminescence of Au nanoparticle (NP) doped polymer blend was performed to understand the plasmonic effects on excited-state dynamics. Hot exciton generation is observed directly at the Au-NP surface, which contributed to achieving a nearly perfect exciton dissociation yield. We found that slow aging of the plasmonic effect and the hot…
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…
Sensitizer exchange dynamics in air and solvent filled semiconductor nanocavities
2010
Multiple dye binding sites and their exchange in equilibrium in air and solvent filled sensitized titanium oxide nanocavities were identified by 2DIR spectroscopy. Binding geometry and flexibility may influence electron injection efficiency of solar cells.