Current-voltage Characteristic Curves Research Articles

Modeling and Simulation of the Photovoltaic Cells for Different Values of Physical and Environmental Parameters

Both research and technological development in the area of renewable energy sources are necessary to account for the increase in energy demand and environment problems in the world. The photovoltaic (PV) cell has been described by non-linear outputs characteristics in current-voltage and power-voltage. This outputs is affected by various effects such as; series resistance ( ), shunt resistance ( ), solar irradiance and temperature. In this paper the effect of variation of parameters has been studied such as series resistance ( ) and shunt resistance ( ) of the diode in the photovoltaic cell and these effects could be seen in the Current-Voltage (I-V) and Power-Voltage (P-V) characteristic curves. In this paper also has been studied the effect of variation of the environmental parameters such as solar irradiance and temperature. Results show that a higher temperature at constant solar irradiance produces a decrease power. So the voltage and the photovoltaic cell output power tend to decrease at higher temperatures, but there is no noticeable effect on the photovoltaic cell current. Thus, it is important to keep the cell temperature as low as possible, because higher temperatures have negative effect on output power of photovoltaic cell. On the other hand, the effect of solar irradiance on photovoltaic cell, it reveals that higher solar irradiance gives higher current and higher power. Shunt resistance has significant effect on the operating characteristic curves of PV cells as low power output is recorded if the value of shunt resistance varies from 0.07 ohms to 1700 ohms. Finally, I have presented power-voltage characteristic curves and current voltage characteristic curves of photovoltaic cell for different solar irradiance in Shkoder, Tirana and Vlore.

Photovoltaic and capacitance measurements of solar cells comprise of Al-doped CdS (QD) and hierarchical flower-like TiO2 nanostructured electrode

This work focuses on the performance of Al-doped CdS quantum dot (QD)/TiO2 solar cells. The devices were analyzed through current-voltage and capacitance-voltage measurements. It was observed from the analysis of absorption spectra that TiO2 nanowires improve the absorption of light of Al doped CdS QDs both in visible and near infrared (NIR) range. Current-voltage characteristics curve of Al doped CdS/TiO2 at different illuminations show that decrease in illumination (from 100 to 5 mW/cm2), affects the voltage and current correspondingly. Power-voltage curve at various intensities of light indicates that power of the solar cell increases with the increase of the bias voltage and reaches its maximum value at each value of light illumination intensity. The peak value of power at maximum illumination is 35 µW at 0.20 V and with decreasing illumination the peak value decreases. Capacitance-voltage measurements reveal that by increasing the bias voltage from −2.0 V to 0 V, the capacitance voltage indicates the rising trend. However, at 5 kHz and 10 kHz frequencies, it was observed that a marginal increase of capacitance was noticed with exceeding bias voltage. The results revealed that subsequent addition of the TiO2 nanowires significantly improved the output performance of QDSSC.

Designing performance enhanced nuclear battery based on the Cd‐109 radioactive source

A dual-effect nuclear battery based on the radio-voltaic and radioluminescence effect was developed, which has the ability to convert nuclear energy into electrical energy with two different modes. Performance-enhanced nuclear batteries are mainly based on the addition of ZnS:Cu radio-luminescent layer to Cd-109 X-ray radioactive source and GaAs radio-voltaic layer. In order to explore the response relationship between the mode of energy conversion and the electrical performance of nuclear battery, the physical model was established to research the deposition energy distribution by using Monte Carlo method. The addition of the radio-luminescent material increases the effective energy deposition of the X-rays and the optimized thickness of ZnS:Cu in such a dual-effect nuclear battery should be set to 560 μm. The current–voltage characteristic curves of the batteries before and after performance optimization were utilized to investigate the electrical properties. Through a comprehensive comparison of Cd-109 nuclear batteries with or without radio-luminescent layer, the simulated results are consistent with experimental results. The results indicate that the electrical performance of dual-effect nuclear battery is significantly higher than that of single radio-voltaic nuclear battery. Moreover, the energy conversion efficiency increases from 0.079% (single radio-voltaic nuclear battery) to 0.119% (dual-effect nuclear battery). The improved performance of the dual-effect nuclear battery provides potential applications for space-based autonomous remote sensors and continuous low-power generation technologies.

Online extraction of physical parameters of photovoltaic modules in a building-integrated photovoltaic system

Building-integrated photovoltaic systems are solar photovoltaic modules that are used to replace traditional building construction materials to generate electrical energy. Photovoltaic modules are generally installed on the roofs or facades of buildings and cannot be monitored by conventional methods. This work presents a new online technique for analysing the current-voltage characteristics of photovoltaic modules installed on the facades of building-integrated photovoltaic systems. The proposed method, which is based on the modified double-diode model, can extract six physical parameters of the photovoltaic module that rely on the current and voltage at the short-circuit and open-circuit points and at the maximum power point. Unlike the approaches from existing studies, the method proposed in this paper requires only the current at the maximum power point. By measuring the solar irradiance, wind speed and average temperature of the photovoltaic module, the current and voltage at the short-circuit and open-circuit points can be calculated. To study the accuracy of the proposed models, the absolute error and root mean square error of individual photovoltaic modules are examined. The results indicate that the minimum absolute error of the current appears near the maximum power point. Moreover, the proposed simulation of the current-voltage characteristic curves achieves a lower root mean square error value and exhibits a better ability to represent the current-voltage characteristics of the photovoltaic modules. In addition, methods are used to extract the six parameters of the photovoltaic module, which operates in the building-integrated photovoltaic system. The experimental results show that the prediction of the current-voltage characteristic curves achieves the lowest root mean square error values at the short-circuit and open-circuit points and at the maximum power point. Furthermore, regardless of whether operating in the building-integrated photovoltaic system, the six parameters of the photovoltaic modules with the same initial characteristics extracted via the proposed methods have similar numerical ranges under standard test conditions. Based on these conclusions, the six parameters based on the modified double-diode model are useful and practical for the simulation and evaluation of the current-voltage characteristics of the photovoltaic module in the building-integrated photovoltaic system.

Mechanism of Charge Transport in Hybrid Organic-Inorganic PEDOT:PSS/Silicon Heterojunctions

Hybrid organic-inorganic heterojunctions have emerged as low-cost alternatives for fabricating optoelectronic devices, but their charge-transport mechanism has not been fully established. In this work, the charge transport in PEDOT:PSS/silicon heterojunctions is found to be governed by a twofold mechanism: injection-limited under reverse bias, space-charge-limited under forward bias. This study provides physical insight into the interpretation of the characteristic current-voltage curves of these and similar hybrid devices.

Experimental and theoretical electrothermal switching mechanism of Ag2O- TeO2- V2O5 glasses

Bulk yAg2O-40TeO2-(60-y)V2O5 glass samples with different molar contents of 0≤ y ≤ 40 mol% were prepared using the normal melt quenching method. The amorphous state has been checked by using the X-ray diffraction. The effect of high electric field on their conductivity was investigated. At low electric fields, the conduction of these samples was ohmic, whearse at high electric fields, bulk samples show nonlinear behavior. Results obtained from the study of voltage-current characteristic curves show an increase in the electric current density along with an increase in deviation from Ohm's law. Moreover, non-ohmic behavior (at the conditions of different ambient temperature and different electrode distances) showed the negative resistance behavior, which was occurred at electrical fields about (104 V/cm). Based upon the joule heating effect in the current filament, the electrothermal model was considered and so, heat dissipation factor and the electrical activation energy were determined. Also, Boltzmann balance energy differential equation (BBEDE) was solved employing finite element method (FEM). It has been approved that Joule heat increases in current filament and after a very short time, temperature and current density increase rapidly (during about 2 μs) in current filament, confirming the electrothermal mechanism.

Important notes on parameter estimation of solar photovoltaic cell

To evaluate the performance of a photovoltaic panel, several parameters must be extracted from the photovoltaic. Among the methods developed to extract photovoltaic parameters from current-voltage (I-V) characteristic curve, metaheuristic algorithms are the most used nowadays. The aim of this paper is to present the inaccuracies occurred in the parameter’s identification of the photovoltaic cell using metaheuristic technics published in Energy Conversion and Management. The results presented by different authors do not meet the objective function. To prove it, an algorithm is proposed to check the accuracy of the proposed results; a simple tool, General Algebraic Modeling System is also proposed to extract the best values of parameters of a photovoltaic cell.

Effect of Oxygen Mixture Ratio on the Properties of ZnO Thin-Films and n-ZnO/p-Si Heterojunction Diode Prepared by RF Sputtering

ZnO thin-films are grown on a p-Si(111) substrate by RF sputtering. The effects of growth temperature and O2 mixture ratio on the ZnO films are investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and roomtemperature photoluminescence (PL) measurements. All the grown ZnO thin films show a strong preferred orientation along the c-axis, with an intense ultraviolet emission centered at 377 nm. However, when O2 is mixed with the sputtering gas, the half width at half maximum (FWHM) of the XRD peak increases and the deep-level defect-related emission PL band becomes pronounced. In addition, an n-ZnO/p-Si heterojunction diode is fabricated by photolithographic processes and characterized using its current-voltage (I-V) characteristic curve and photoresponsivity. The fabricated n-ZnO/p-Si heterojunction diode exhibits typical rectifying I-V characteristics, with turn-on voltage of about 1.1 V and ideality factor of 1.7. The ratio of current density at ± 3 V of the reverse and forward bias voltage is about 5.8 × 103, which demonstrates the switching performance of the fabricated diode. The photoresponse of the diode under illumination of chopped with 40 Hz white light source shows fast response time and recovery time of 0.5 msec and 0.4 msec, respectively.

Theory and simulations of spherical and cylindrical Langmuir probes in non-Maxwellian plasmas

The collected current by spherical and cylindrical Langmuir probes immersed in an unmagnetized and collisionless non-Maxwellian plasma at rest are theoretically studied, and analytical expressions for the currents of attracted and repelled plasma particles are presented. We consider Kappa, Cairns and the generalized Kappa–Cairns distributions as possible models for the velocity field in the plasma. The current–voltage characteristics curves are displayed and discussed. Furthermore, comparisons with the collected currents in Maxwellian plasmas are given. The results of Particle-in-Cell (PIC) simulations of spherical and cylindrical probes in non-Maxwellian plasmas are also presented, and compared with the theoretical expressions. The results for the collected currents by the Langmuir probes obtained by PIC simulations are in good agreement with the corresponding analytical expressions.

Rectifying Characteristics of Thermally Treated Mo/SiC Schottky Contact

The rectifying characteristics of a Mo/SiC Schottky contact fabricated by facing targets sputtering system were investigated through current–voltage measurement. The Schottky diode parameters were extracted from the forward current–voltage characteristic curve by the Cheung and Cheung method and the Norde method. The as-deposited Mo/SiC Schottky contacts possessed Schottky barrier heights of 1.17 and 1.22 eV, respectively. The Schottky barrier heights of the diodes were decreased to 1.01 and 0.91 eV after annealing at 400 °C for 30 min. The ideality factor was increased from 1.14 and 1.08 to 1.51 and 1.41, respectively. This implies the presence of non-ideal behaviors due to a current transport mechanism other than ideal thermionic emission, and the non-ideal behaviors increased as a result of excessive thermal annealing. In contrast, only a negligible change was observed in the crystallographic characteristics. This result suggests that the reason for the deviation from the ideal rectifying characteristics of the Mo/SiC Schottky contact through the annealing process was the variation in the current transport mechanism, including recombination, tunneling, and/or minority carrier injection.

Study the effect of cathode geometry on I-V characteristics of nitrogen dc glow discharge

In this paper, the I-V characteristic of a dc glow discharge are studied with the aim of determine the performance a good parametersfor stable operation of the plasma. Nitrogen plasma produced by dc glow discharge is the investigated with a manypurpose of studying plasma phenomena, the discharge system consists of two electrodes, the cathode forms various geometrical shapes and anode as a disc- shaped with diameter (8.8cm). The electrodes are enclosed in a large cylindrical glass chamber of pyrex filled with nitrogen gas. Two important physical parameters affecting the condition of the discharge are the gas pressure and constant inter-electrode distance. The discharge current-voltage (I-V) characteristic curves of the discharge were measured at variable pressure and the inter-electrode spacing, Current-voltage characteristics visualization of the discharge indicate that the discharge is take place in the normal glow region. The (I-V) characteristics of nitrogen gas discharge were deduced as a plasma system operated in normal glow discharge nitrogen, which is very important parameter in the sputtering and deposition. Also, the discharge current is increased for nitrogen plasma discharge with the increasing of the working pressure lead to increase the deposition rate.DIO.: http://dx.doi.org/10.31257/2018/JKP/2019/110110

A Bio-memristor with Overwhelming Capacitance Effect

A bio-memristor, which was prepared using the bio-materials as basic components, has being become the focus of research owing to the potential application as medical diagnosis in biomedical field. Herein, an environmentally-friendly and sustainable bio-memristor device with Ag/walnut skin (WS)/ITO structure was fabricated, in which an obvious and reliably repeated rectangular current–voltage characteristic curve is observed. Our result shows that the WS, an useless bio-material, can be used to fabricate electronic devices after proper processing. Finally, the memory mechanism based on the conductive filament mode associated the capacitance effect is ascribed. This work has opened a new way to exploit the next generation bio-electronic device with advantages of environmentally-friendly, sustainable and pollution-free.

Simulation and measurement of millimeter-wave radiation from Josephson junction array**Project supported by the National Natural Science Foundation of China (Grant No. 51002081), the Fundamental Research Funds for the Central Universities, China, the China Manned Space Advance Research Program, China (Grant No. 030201), and the Research Program of Application Foundation and Advanced Technology of Tianjin, China (Grant No. 15JCQNJC01300).

We report the circuit simulations and experiments of millimeter-wave radiation from a high temperature superconducting (HTS) bicrystal Josephson junction (BJJ) array. To study the effects of junction characteristic parameters on radiation properties, new radiation circuit models are proposed in this paper. The series resistively and capacitively shunted junction (RCSJ) models are packaged into a Josephson junction array (JJA) model in the simulation. The current-voltage characteristics (IVCs) curve and radiation peaks are simulated and analyzed by circuit models, which are also observed from the experiment at liquid nitrogen temperature. The experimental radiation linewidth and power are in good agreement with simulated results. The presented circuit models clearly demonstrate that the inconsistency of the JJA will cause a broad linewidth and a low detected power. The junction radiation properties are also investigated at the optimal situation by circuit simulation. The results further confirm that the consistent JJA characteristic parameters can successfully narrow the radiation linewidth and increase the power of junction radiation.

Characterization of an InAs/GaSb type-II superlattice barrier photodetector operating in the LWIR domain

In this paper, structural, optical and electrical characterizations of longwave infrared barrier detectors based on the InAs/GaSb superlattice are reported and analyzed. The fabricated detectors exhibited a 50% cut-off wavelength around 10.5 μm at 80K measured by photoluminescence and spectral response. The dark current density was 8.4×10-4 A/cm2 at 80K and a performance analysis combining spectral response, dark current-voltage characteristic and capacitance-voltage measurement curves was performed to determine the operating bias and the dark current regimes at different biases. Dark current simulations were also performed to better understand limiting dark current mechanisms of the device performance.

Constructing Metal Arch Nanobridges Utilizing a Photothermal‐Induced Nanobonding Technique

AbstractConstruction of multilayered arch nanobridges and nanocantilever structures consisting of silver nanowires using a photothermal‐induced nanobonding technique is demonstrated. The fabricated nanobridges are of different height (300 nm to 20 µm) and span (25–70 µm). Their current–voltage characteristic curves indicate superior electrical connection between the metal nanowires and the abutments (gold thin film). Moreover, super mechanical strength of these arch nanobridges and nanocantilevers is demonstrated by putting gold nanoplates (a few tens of nm thick, a few tens of µm in diameter, and a maximum weight of 3 pN—about 20 times heavier than the silver nanowire of same length) on top of these nanostructures. The multilayered arch nanobridges demonstrate their potential applicability as short‐circuit‐free multipronged electronic connections in nanoelectronic devices. Furthermore, by recording the change in vibration frequency due to proximity of foreign contamination, these nanobridges and the nanocantilevers can be utilized to identify them; that is, these nanostructures can be used as biological sensors to detect viruses, bacteria, and other pathogens.

Layer-by-layer MoS2:GO composite thin films for optoelectronics device applications

With reference of our previous report (Appl. Surf. Sci. 474(2019)227), the molybdenum disulphide (MoS2) thin film were prepared by the dip-coating technique at different temperatures (400 °C–450 °C) using methanolic solution of ammonium molybdate and ammonium thiocyanate that are used as bare-substrate for the deposition of graphene oxide (GO) thin films. For the deposition of graphene oxide (GO), commercially purchased GO (0.5 mg in 10 mL aqueous solution) was deposited by dip-coating technique on dip-deposited MoS2 thin film to make layer-by-layer MoS2:GO composite thin films and hence studied their electronic and electrical behaviours. The micro-structural and surface morphology were studied using Raman spectroscopy, X-ray diffraction (XRD) and field emission scanning electron microscopy, whereas optical band estimated from the optical absorption spectra. The electronic structure and their bonding properties were studied using X-ray photoelectron spectroscopy and the electrical behaviours were observed from the current-voltage (I-V) characteristic curve. The formation of different phases of MoS:GO thin films show an enhanced electronic and electrical performance due to their unique-structure and the synergetic effect of MoS2:GO nanosheets when compared to those of bare MoS2.

Computational modeling and experimental analysis of heterojunction with intrinsic thin-layer photovoltaic module under different environmental conditions

This paper focuses on four parameter single-diode model applied to a heterojunction with intrinsic thin-layer module. Matlab software was used to carry out the simulations of current-voltage (I–V) characteristic curves under varying irradiance and temperature conditions. Accuracy of the model was verified by outdoor measurements at different irradiance and temperature values. Series resistance as well as diode ideality factor were extracted from the modeling results. Relative errors were calculated for three main points of I–V characteristic curve: open circuit voltage, short circuit current and maximum power point. Root mean square errors of I–V curves were also computed. Analysis shows high accuracy of the model at considered conditions in case of open circuit voltage with up to 0.27% of maximum relative error and short circuit current with about 0.5% of relative error. Good agreement between simulated and measured values of maximum power points was also noticed at irradiance levels from 600 W/m2 to 1000 W/m2 (about 1% of relative errors). Calculated RMSE value of about 0.6% at high irradiances confirms high level of accuracy of presented model in application to a heterojunction with intrinsic thin-layer module.

Dielectric properties and I-V characteristics of Li0.5La0.5TiO3 solid electrolyte for ceramic supercapacitors

Solid electrolyte is crucial important for the developing of next generation supercapacitors. Tetragonal perovskite Li0.5La0.5TiO3 (LLTO) solid electrolyte ceramics were prepared by using conventional solid-state reaction method. Clear interfaces between the metal electrodes (Ag, Au or Pt) and the LLTO ceramics were observed. Nominal colossal permittivity at low frequency and strong frequency dispersion were observed in LLTO samples with different metal electrodes. The leakage currents decrease exponentially after the application of a stepwise DC voltage and show dramatic differences between different electrodes. The current-voltage (I-V) characteristic curves also indicate the differences, where the peak currents at maximum 5 V loading are 5.1 nA for sample with Ag electrode, 138.9 nA for Au electrode and 13.5 μA for Pt electrode. In addition, there is a clear redox current peak at about 4 V in LLTO/Pt sample and a blurred peak in LLTO/Au sample at around 2 V, which indicates an electrochemical reaction between LLTO and Pt/Au electrodes. These differences are attributed to the redox reaction of the Schottky contact interface between samples and electrodes. These interfacial I-V characteristics between LLTO and metal electrodes help us to understand the underlying mechanism in the future solid electrical double layer ceramic supercapacitors.

Enhanced Vibrating Particles System Algorithm for Parameters Estimation of Photovoltaic System

To evaluate the performance of a photovoltaic panel, several parameters must be extracted from the photovoltaic. These parameters are very important for the evaluation, monitoring and optimization of photovoltaic. Among the methods developed to extract photovoltaic parameters from current-voltage (I-V) characteristic curve, metaheuristic algorithms are the most used nowadays. A new metaheuristic algorithm namely enhanced vibrating particles system algorithm is presented here to extract the best values of parameters of a photovoltaic cell. Five recent algorithms (grey wolf optimization (GWO), moth-flame optimization algorithm (MFOA), multi-verse optimizer (MVO), whale optimization algorithm (WAO), salp swarm-inspired algorithm (SSA)) are also implemented on the same computer. Enhanced vibrating particles system is inspired by the free vibration of the single degree of freedom systems with viscous damping. To extract the photovoltaic parameters using enhanced vibrating particles system algorithm, the problem can be set as an optimization problem with the objective to minimize the difference between measured and estimated current. Four case studies have been implemented here. The results and comparison with other methods exhibit high accuracy and validity of the proposed enhanced vibrating particles system algorithm to extract parameters of a photovoltaic cell and module.

Parameter extraction of photovoltaic models from measured I-V characteristics curves using a hybrid trust-region reflective algorithm

Accurate, efficient and reliable parameter extraction of solar photovoltaic (PV) models from the measured current-voltage (I-V) characteristic curves is important for evaluation, modelling, and diagnosis of the actual operating state of in-situ PV arrays. In recent years, numerical heuristic optimization algorithms based parameter extraction methods have been proposed. However, the efficiency and reliability of these methods are limited due to heuristic or stochastic searching strategies. In this paper, by combining the trust-region reflective (TRR) deterministic algorithm with the artificial bee colony (ABC) metaheuristic algorithm, a new hybrid algorithm ABC-TRR is proposed to improve the parameter extraction of PV models. The ABC-TRR algorithm combines the global exploration capability of the ABC and the local exploitation of the TRR, which achieves a good tradeoff among accuracy, convergence and reliability. The proposed ABC-TRR hybrid algorithm is evaluated and compared with other state-of-the-art algorithms using the standard I-V curves of the benchmark Photowatt-PWP201 PV module and RTC France solar cell as well as the measured I-V curves of a laboratory PV module/string/array. Comprehensive experimental analysis and comparison results demonstrate that the proposed ABC-TRR algorithm achieves the same level of accuracy as the best reported algorithms with the highest overall reliability. More importantly, the ABC-TRR algorithm converges 4.69 times faster than the best-reported algorithms on average. In view of these advantages, the proposed ABC-TRR algorithm is a promising alternative for accurately, efficiently and reliably extracting the parameters of PV models from measured I-V curves. In addition, it was experimentally demonstrated that the parameter extraction result can be used to indicate the partial shading and abnormal degradation conditions.