Search results for "Volt"
showing 10 items of 2187 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…
Comparison between textured SnO2:F and Mo contacts with the p-type layer in p–i–n hydrogenate amorphous silicon solar cells by forward bias impedance…
2013
Abstract In this paper we compare the performance of the textured SnO2:F and Mo contacts with the p-type layer in p–i–n hydrogenate amorphous silicon (a-Si:H) solar cells. We use standard current–voltage (I–V) electrical characterization methods coupled with forward bias small signal impedance analysis. We show the efficacy of this technique to determine the effective carrier lifetime in photovoltaic cells. We show that such effective lifetimes are indeed directly connected to the respective dark diode saturation currents. We also find that the effective lifetime is constant with the temperature in the 0–70 °C range and it is significantly better for the solar cell with Mo diode contact. Th…
An accurate one-diode model suited to represent the current-voltage characteristics of crystalline and thin-film photovoltaic modules
2020
Abstract In this paper a new one-diode model, conceived in order to be used to represent the current-voltage curves of both crystalline and thin-film photovoltaic modules, is presented. The model parameters are calculated from the information contained in the datasheets issued by manufactures by means of simple iterative procedures that do not require the assumption of simplifying hypotheses. Some innovative relations describing the dependence of the parameters from the solar irradiance and cell temperature are adopted in order to permit the model to reliably simulate the electrical behaviour of photovoltaic devices operating in real conditions. The ability of the model to calculate the cur…
Plasmonic modes in molybdenum ultra-thin films suitable for hydrogenated amorphous silicon thin film solar cells
2014
We have recently demonstrated that molybdenum ultra-thin films interposed between hydrogenated amorphous silicon (a-Si:H) and SnO2:F transparent conductive oxide (TCO) in thin film solar cells show light trapping effects which enhance the solar cells performances. The effect of this improvement may be attributed to surface plasmon polariton (SPP) modes excited at the molybdenum interface by the solar radiation. In this paper we show direct evidence of such SPP modes in the case of the molybdenum/air interface by using the attenuated total reflection (ATR) technique, pioneered by Kretschmann, and we evaluate the dielectric constant of molybdenum at 660 nm. (C) 2013 The Authors. Published by …
Development of a test station for accurate in situ I-V curve measurements of photovoltaic modules in Southern Norway
2011
The development of an outdoor test station for accurate in situ I-V curve measurements of photovoltaic (PV) modules is described. The modules are installed in an open-rack configuration at the University of Agder in Southern Norway. Seven new and three aged PV modules of different type and make are being tested, including mono-and multicrystalline silicon from differing manufacturing routes, triple-junction amorphous silicon, and CIS. Data acquisition is controlled with a multichannel electronic load system and LabVIEW software, recording high-resolution I-V curves at one-minute intervals. Between I-V curve sweeps, each module is operated at the maximum power point. Characteristic electrica…
Algebraic real-time algorithm for B-Spline sinusoidal pulse width modulation in three phase voltage source inverters.
2008
In this paper a novel algebraic real-time algorithm for implementation of sinusoidal pulse width modulation (SPWM) based on B-spline carriers is introduced and discussed. B-spline functions are used as carrier signals with the aim to to reduce harmonic content of the three phase inverter output voltage. This algorithm eliminates the problem of B-spline recursive evaluation with convolution integrals or convolution sums in digital counterpart. The pulse pattern synthesis is made with the help pre-calculated duty cycle expressions. In this way the carrier signals have not to be really synthesized, hence the hardware and the whole inverter control system becomes cheaper, more reliable and affo…
Cyclam-functionalized silica-modified electrodes for selective determination of Cu(II)
2009
Cyclam derivatives have been grafted via 1, 2 or 4 silylated arms to the surface of mesoporous silica and the resulting materials have been incorporated into carbon paste electrodes and applied to the preconcentration electroanalysis of Cu(II). Sensitive and selective detection of the target analyte was achieved owing to the attractive binding properties of this macrocyclic ligand towards Cu(II) species. Various parameters likely to affect the preconcentration and detection steps have been studied, including pH of the accumulation medium, composition of the detection solution, structure and composition of the adsorbent, accumulation time, or presence of potentially interfering species. In p…
Evidence of tetraphenylporphyrin monoacids by ion-transfer voltammetry at polarized liquid|liquid interfaces
2008
We present a simple methodology to illustrate the existence of tetraphenylporphyrin monoacid based on ion-transfer voltammetry at a polarized water|1,2-dichloroethane interface and organic pK values are also estimated.
Theoretical study on the influence of electric field direction on the photovoltaic performance of aryl amine organic dyes for dye-sensitized solar ce…
2019
It is very important to reveal the influence of different electric field directions on dye sensitizers. Thus, in this study, we investigated the electronic structures and optical properties of six designed aryl amine organic dye models under different electric fields using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Moreover, the electronic structures and optical properties of these studied dyes with different electric field in tetrahydrofuran (THF) were also calculated. The key parameters of the short-circuit current density (Jsc), including light harvesting efficiency (LHE) and intra-molecular charge transfer (ICT), are discussed in detail. With …
Physicochemical characterization of metal hexacyanometallate–TiO2composite materials
2015
The paper describes the synthesis and characterization of novel TiO2–metal hexacyanometallates (MHCMs) composite materials. The starting material, TiO2, was modified by addition of cobalt-hexacyanoferrate (CoHCF) or iron-hexacyanocobaltate (FeHCC) at various concentrations. The resulting composites were characterized as follows: cyclic voltammetry (CV) followed the formation of TiO2–MHCM clusters, TEM micrographs studied their morphology, XAS and XPS data indicated that MHCM bonds to TiO2 through the nitrogen atom of its –CN group and modifies the environment of Ti compared to that of pure anatase. As expected, and confirmed by UV-Vis and XP-valence band data, the electronic properties of T…