Search results for "Volt"
showing 10 items of 2187 documents
Deep insight into electron transport and photovoltaic parameters in DSSCs
2019
Dye-sensitized solar cells (DSSCs) based on titanium (IV) oxide (TiO2) nanoparticles and nanotubes (NTs) with different weight ratios and phase compositions were fabricated. The obtained nanostructures were investigated using X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and ultraviolet–visible spectroscopy. Current–voltage measurements and electrochemical impedance spectroscopy were used to investigate the electron transport and photovoltaic performance of DSSCs. An increase of 14% in cell efficiency was achieved by introducing 10 wt% NTs. In this configuration, high dye loading is ensured and substantial improvement in electron transport efficie…
Ion track template technology for fabrication of CdTe and CdO nanocrystals
2020
Abstract CdTe and CdO nanocrystals were synthesized by chemical deposition into a-SiO2/n-Si ion track template formed by 200 MeV Xe ion irradiation with the fluence of 108 ions/cm2. Depending on the temperature of the solution CdTe + CdO and single-phase CdO with a hexagonal crystal structure were obtained, respectively. The study of the current – voltage characteristics of the obtained structure with the single-phase CdO allows us to estimate the number of grain boundaries and the height of the potential barrier, as well as the n-type conductivity.
Radiation resistance of nanolayered silicon nitride capacitors
2020
Abstract Single-layered and multi-layered 20–60 nm thick silicon nitride (Si3N4) dielectric nanofilms were fabricated using a low-pressure chemical vapour deposition (LPCVD) method. The X-ray photoelectron spectroscopy (XPS) confirmed less oxygen content in the multi-layered nanofilms. The capacitors with Si3N4 multilayer demonstrated a tendency to a higher breakdown voltage compared to the capacitors with Si3N4 single layer. Si3N4 nanofilms and capacitors with Si3N4 dielectric were exposed to 1 kGy dose of gamma photons. Fourier transform infrared (FTIR) spectroscopy analysis showed that no modifications of the chemical bonds of Si3N4 were present after irradiation. Also, gamma irradiation…
The Acoustic Wave Behavior Within the PEA Cell for Space Charge Measurement
2018
In order to evaluate the acoustic wave behavior within the Pulsed Electro Acoustic (PEA) cell, a simulation model has been developed in this work. The model, implemented in Matlab environment, is based on the analogy between acoustic and electrical quantities. Therefore, it was possible to model the PEA cell as cascade connected lossy transmission lines. The model has been validated theoretically by making a comparison with a simulation result found in literature. The experimental validation has also been made by using the PEA cell of the LEPRE high voltage lab. In addition, four graphs have been realized. Two of them can be used to establish in easy and fast way to obtain the minimum groun…
The ${JV}$ -Characteristic of Intermediate Band Solar Cells With Overlapping Absorption Coefficients
2017
An analytic expression for the $\textit {JV}$ -characteristic of intermediate band (IB) solar cells with overlapping absorption coefficients is derived. The characteristic contains six voltage-independent parameters that are calculated from material properties, cell properties, and external conditions. Combined with exponential functions containing the cell voltage, these describe the full $\textit {JV}$ -characteristic. Expressions are also derived for the short-circuit current and open-circuit voltage. The model represents a major simplification compared with the existing model for this type of devices. The simplicity will facilitate the understanding of the operation of such cells. Furth…
An Analytic Approach to the Modeling of Multijunction Solar Cells
2020
Analytic expressions for the $JV$ -characteristics of three types of multijunction configurations are derived. From these, expressions for the short-circuit current, open-circuit voltage, and voltage at the maximum power point are found for multiterminal devices, and for series-connected tandem stacks. For voltage-matched devices, expressions for the optimal ratio of the number of bottom cells to the number of top cells are established. Luminescent coupling is incorporated throughout the article. It should be highlighted that the maximum power point of a series-connected tandem stack is described, with good accuracy for all interesting band gap combinations, by a single analytic expression.…
The Role of Right Interpretation of Space Charge Distribution for Optimized Design of HVDC Cables
2019
In the field of high-voltage transmission systems, different degradation phenomena affect the reliability of the employed components. In particular, under dc stress, the space charge accumulation phenomenon is believed to be the most responsible of the dielectrics lifetime reduction. To measure the accumulated space charges in flat specimens, the pulsed electro-acoustic (PEA) method is one of the most used techniques. The working principle of the PEA cell is based on the acoustic waves propagation and detection. As is well known, the acoustic waves propagating in different means are partially transmitted and partially reflected. Therefore, the piezoelectric sensor of the PEA cell is subject…
Efficiency of gyrotrons with a tapered magnetic field in the regime of soft self-excitation
2018
As a rule, gyrotron operation with high efficiency is realized in the regime of hard self-excitation that requires a special start-up scenario: either a tuning of the external magnetic field or providing certain relations between mod-anode and beam voltages. This paper describes a study of gyrotron operation in slightly tapered external magnetic fields. It is shown how the use of tapered magnetic fields affects the maximum efficiency realizable in hard and soft excitation regimes. First, a model of gyrotron with the Gaussian axial profile of the resonator field is studied. Then, a similar treatment is done for a realistic resonator designed for a 140 GHz Karlsruhe Institute for Technology g…
Temperature Coefficients of Solar Cell Parameters at Maximum Power Point
2020
Analytical expressions for the temperature coefficients of the maximum power point voltage and current are presented. The temperature coefficients are calculated assuming the bandgap to be a linear function of the temperature and accounting for energy losses of non-radiative nature. The latter are introduced in the model through the External Radiative Efficiency. The so-called $\gamma$ parameter, which has been shown to account for the thermal sensitivity of all mechanisms determining the open-circuit voltage, appears to also play a role in the temperature coefficient of the maximum power point voltage and current. Numerical results and a comparison with experimental measurements are also p…
Radiation hardness studies of CdTe and for the SIXS particle detector on-board the BepiColombo spacecraft
2009
Abstract We report of the radiation hardness measurements that were performed in the developing work of a particle detector on-board ESA's forthcoming BepiColombo spacecraft. Two different high- Z semiconductor compounds, cadmium telluride (CdTe) and mercuric iodide (HgI 2 ), were irradiated with 22 MeV protons in four steps to attain the estimated total dose of 10 12 p / cm 2 for the mission time. The performance of the detectors was studied before and after every irradiation with radioactive 55 Fe source Mn K α 5.9 keV emission line. We studied the impact of the proton beam exposure on detector leakage current, energy resolution and charge collection efficiency (CCE). Also the reconstruct…