Search results for "CIRCUIT"

Graded Carrier Concentration Absorber Profile for High Efficiency CIGS Solar Cells

2015

We demonstrate an innovative CIGS-based solar cells model with a graded doping concentration absorber profile, capable of achieving high efficiency values. In detail, we start with an in-depth discussion concerning the parametrical study of conventional CIGS solar cells structures. We have used the wxAMPS software in order to numerically simulate cell electrical behaviour. By means of simulations, we have studied the variation of relevant physical and chemical parameters-characteristic of such devices-with changing energy gap and doping density of the absorber layer. Our results show that, in uniform CIGS cell, the efficiency, the open circuit voltage, and short circuit current heavily depe…

Lumped parameter approach of nonlinear networks with transistors

1991

In this chapter we study the lumped parameter modelling of a large class of circuits composed of bipolar transistors, junction diodes and passive elements (resistors, capacitors, inductors). All these elements are nonlinear: the semiconductor components are modelled by “large signal” equivalent schemes, the capacitors and inductors have monotone characteristics while the resistors can be included in a multiport which also has a monotone description.

Anodic growth of passive layers on steel rebars in an alkaline medium simulating the concrete pores

2006

Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques have been used to study passive layers anodically grown on steel rebars in an aqueous alkaline solution simulating the electrolyte of the concrete pores. Nyquist diagrams recorded by EIS at the different stabilization potentials show a diffusional tail at low frequencies. The analysis of the impedance measurements has been made by means of an equivalent circuit with a Warburg component and within the framework of the point defect model (PDM) theory. It is observed that the calculated concentration of vacancies is a function of the potential in accordance with the theoretical prediction of the PDM.

Transient drift‐diffusion simulation of the open circuit voltage decay in ionic perovskite solar cells

2021

Plasmonic Waveguides Co-Integrated with Si3N4 Waveguide Platform for Integrated Biosensors

2019

Integration of plasmonic waveguides with low-loss photonic platforms have attracted research efforts as the means to benefit from the extra-ordinary features of plasmonics while enhancing the functional portfolio of Photonic Integrated Circuits (PICs). In this work, we review a technology platform that integrates water cladded plasmonic waveguides integrated in a low-loss Si 3 N 4 photonic platform, targeting biosensing applications. Results obtained experimentally and numerically will be presented with respect to propagation losses, interface coupling loss and accumulated phase change per unit length, showing how Surface Plasmon Polariton (SPP) waveguides can be effectively combined with p…

Superior energy density through tailored dopant strategies in multilayer ceramic capacitors

2020

The Gerson–Marshall (1959) relationship predicts an increase in dielectric breakdown strength (BDS) and therefore, recoverable energy density (Wrec) with decreasing dielectric layer thickness. This relationship only operates however, if the total resistivity of the dielectric is sufficiently high and the electrical microstructure is homogeneous (no short circuit diffusion paths). BiFeO3–SrTiO3 (BF–ST) is a promising base for developing high energy density capacitors but Bi-rich compositions which have the highest polarisability per unit volume are ferroelectric rather than relaxor and are electrically too conductive. Here, we present a systematic strategy to optimise BDS and maximum polaris…

Thermogalvanic corrosion of Alloy 31 in different heavy brine LiBr solutions

2012

Thermogalvanic corrosion generated between two electrodes of Alloy 31, a highly-alloyed austenitic stainless steel (UNS N08031), has been investigated imposing different temperature gradients in three deaerated LiBr solutions, under open circuit conditions by using a zero-resistance ammeter (ZRA). Besides EIS spectra were acquired in order to explain the obtained results. On the whole, cold Alloy 31 electrodes were anodic to hot Alloy 31 electrodes, since an increase in temperature favoured the cathodic behaviour of the hot electrode. Thermogalvanic corrosion of Alloy 31 in the LiBr solutions studied was not severe, although it negatively affects the corrosion resistance of the cold anode. …

Characterization process to measure the electrical contact resistance of Gas Diffusion Layers under mechanical static compressive loads

2016

AEM2016. International conference on Advanced Energy Materials, University of Surrey, Guildford, ROYAUME-UNI, 12-/09/2016 - 14/09/2016; Recent research has identified the mechanical properties of the fuel cell internal components (in particular, the Gas Diffusion Layers - GDLs) as key-parameters to obtain high final performances of the generator. The mechanical compression modulus of these components, the stability of their mechanical properties with respect to temperature and humidity, and their ability to interact with water have an impact on the electrical contact resistances in the stack and, by consequence, on the overall performance of the electric generator. Reducing the losses by co…

Series resistance determination and further characterization of c-Si PV modules

2012

Abstract This paper presents a new algorithm for determination of the series resistance of crystalline-Si PV modules from individual illuminated I–V curves. The ideality factor and the reverse saturation current are then extracted in the classic way. The approach is applied to in-situ measured data from modules based on two types of mc-Si feedstock. The results indicate that the method yields physically meaningful parameters. An improved definition of local ideality factor is suggested, resulting in m-V plots unaffected by the series resistance. In addition, m-I plots are introduced for the first time. The novel differential techniques reveal an unexpected rise of the ideality factor at ope…

High voltage vacuum-deposited CH3NH3PbI3-CH3NH3PbI3 tandem solar cells

2018

The recent success of perovskite solar cells is based on two solid pillars: the rapid progress of their power conversion efficiency and their flexibility in terms of optoelectrical properties and processing methods. That versatility makes these devices ideal candidates for multi-junction photovoltaics. We report an optically optimized double junction CH3NH3PbI3–CH3NH3PbI3 tandem solar cell where the matched short-circuit current is maximized while parasitic absorption is minimized. The use of an additive vacuum-deposition protocol allows us to reproduce calculated stack designs, which comprise several charge selective materials that ensure appropriate band alignment and charge recombination…