Junction Recombination Velocity Research Articles

Comparative study of the effects of simulation models on the electronic and electrical parameters of a silicon pv cell


 For silicon solar cells simulation studies, one dimensional (1D), two dimensional 2D) and t
 
 hree dimensional (3D) models are used. Depending of model proposed and assumptions done for the study, the electronic and electrical parameters and then the performance of the solar cell can be influenced.
 This situation raises the problem of the relevance of the choice of the study model and the quality of the resulting results. This work, propose comparative study of the electronic and electric parameters of 1D model, 3D analytical model and 3D empirical model. In this study, continuity equations of excess minority electrons are solved for 1D and 3D models and analytical expressions of electronic parameters (density of electrons δ, intrinsic junction recombination velocity Sf0 and recombination velocity at back surface Sb) and electric parameters (Jsc, Voc, η) are derived. The influence of the model chosen on the electric and electronic parameters of the PV cell have been presented.
 It appears in this study that the choice of the simulation model has a large influence on the electronic and electrical parameters the PV cell. The one-dimensional formulation (1D) overestimates the solar cell efficiency comparatively to the three-dimensional (3D) formulations. The study put in evidence also that for the same grain size, the solar cell efficiency resulting of 3D classical formulation is overestimates than one resulting of 3D empirical formulation.
 

Influence of the Magnetic Field on the Diffusion Capacitance of a Serial Vertical Junction Silicon Solar Cell in Frequency Modulation

In this work, a theoretical study of the effect of the magnetic field on the minority charge carrier density and the diffusion capacity of a silicon solar cell with vertical junction in series in dynamic frequency regime, is done. From the relative continuity equation of the minority charge carriers’ density we establish the boundary condition at the junction and the base medium. The expression of the density of minority carriers of charges in the base, allows us to determine the capacity of diffusion of the solar cell according to the magnetic field, the frequency of modulation, the wavelength of illumination and a junction recombination velocity. The profile of the diffusion coefficient allowed us to make a choice on the values of the magnetic field. These values of the magnetic field intensity will be fixed throughout this article. Each value of the magnetic field strength corresponds to a well-defined value of the resonance frequency. We obtained two ranges of illumination wavelengths from the minority charge carrier’ density profile. The influence of the magnetic field on the diffusion coefficient, of the density of minority charge carriers in short-circuit and open-circuit conditions and of the diffusion capacity, for a specific wavelength, is theoretically studied.

Theoretical Study of a Bifacial Silicon Solar Cell Front Side Illuminated: Magnetic Field Effect on the Recombination Velocities Inducing the Short Circuit and Limiting the Open Circuit

The aim of this work is to present a study of the recombination velocities at the junction initiating the shortcircuit (Sfsc) and limiting the open circuit (Sfoc) of a silicon solar cell under magnetic field in the static regime. From the continuity equation, the density of minority charge carriers in the base, the photocurrent density, and the phototension are determined. The study of the photocurrent density and the phototension, as a function of the junction recombination velocity, makes it possible to determine the recombination velocities at the junction initiating the short-circuit and limiting the open circuit respectively. From the profile of the variation of the photocurrent density and of the phototension as a function of the junction recombination velocity, a technique for determining the junction recombination velocities initiating the short circuit situation and limiting the open circuit is presented.

A Junction Electric Field Determination of a Bifacial Silicon Solar Cell under a Constant Magnetic Field Effect by Using the Photoconductivity Method

In this work, a theory based on the steady photoconductivity method, of a bifacial silicon solar cell under polychromatic illumination and a magnetic field effect, is presented. The resolution of the continuity equation in the base of the solar cell, allowed us to establish the expression of the minority carriers’ density from which the photoconductivity, the photocurrent density, the photovoltage and the solar output power as function of the junction recombination velocity and the applied magnetic field, were deduced. From I-V and P-V characteristics of the solar cell, optimal photovoltage and optimal photocurrent obtained at the maximum power point corresponding to a given operating point which is correlated to an optimal junction recombination velocity, were determined according to the magnetic field. By means of the relation between the photocurrent density and the photoconductivity, the junction electric field has been determined at a given optimal junction recombination velocity.

Study of the static characteristic I-V and the electrical parameters corresponding to the shunt resistance Rsh and series resistance Rs per unit area of a solar cell with grain size

This paper presents a new technique based on the junction recombination velocity (Sf: junction recombination velocity) at the grain size for the evaluation of the series and shunt resistances. The study of the response of the solar cell and the parameters of recombination in grain size, which are the object of the investigation, is related to the study of the static characteristic I-V and electrical parameters Rs and Rsh under a magnetic field. This study has allowed us to address some of the theoretical aspects of the field solar cell in order to draw a conclusion and some perspectives. Based on the results obtained for the photocurrent density and the photovoltage, we will study the I-V characteristic of the solar cell to then be able to propose a model for the determination of the shunt resistance Rsh and the series resistance Rs. Series resistance investigations, including numerical simulations and field data tests, are conducted to examine the energetic behavior of the PV modules for efficiency. Experimental results show that the proposed direct resistance-estimation method allows the PV modules to achieve their maximum power and efficiency under various operation conditions.

Determination of the Solar Cell Optimal Junction Recombination Velocity Using Hybrid Method

In this paper we present a technique for determining the optimum junction recombination velocity of a solar cell, using a combination of the electrical equivalent model, and the finite element method. Starting from the continuity equation that describes the solar cell operation solved in one dimension by the finite element method, the excess minority carrier’s density is determined. From this density, the photocurrent, the photovoltage and the power produced by the solar cell are determined. The photocurrent and the photovoltage are represented according to the junction recombination velocity, as well as the solar cell power versus the photovoltage, for various values of the series resistance. In considering its equivalent electrical model, the solar cell is modeled and simulated with Matlab/Simulink. In this simulation model, the capacitor initially discharged, charges under the effect of the solar cell. Its impedance varying according to time, represents the load resistance which corresponds to an operating point of the solar cell. During the capacitor charge process for various values of the series resistance, we obtain the current-voltage characteristic of the solar cell in order to highlight the series resistance effects on the solar cell power. From the optimal value of the power, and that of solar cell photovoltage obtained by simulating the solar cell using Matlab/Simulink, the value of the junction recombination velocity corresponding to the maximum value of the solar cell power is determined numerically, for various values of the series resistance.

Effect of Illumination Wavelength on the Extension of the Space Charge Regions of Photovoltaic Capacitance Efficiency

The effect of the illumination wavelength on the vertical parallel silicon solar cell n-p junction with electrical parameters by use extension space charge region method is theoretically analyzed. Based on the excess minority carrier’s density, the photocurrent density and photovoltage across the junction was determined. From both photocurrent and the photovoltage, the series and shunt resistance expressions are deduced and the solar cell associated capacitance (open-circuit and short-circuit) and conversion efficiency are calculated. Wavelength dependence in the initial part with moderate junction recombination velocity modulation by use extended space charge region method. This influence is attenuated in polycrystalline silicon solar cells with wavelength in the space charge region. A theoretical discussion about the wavelength dependence of the cell efficiency is also reported.

Junction Surface Recombination Concept as Applied to Silicon Solar Cell Maximum Power Point Determination Using Matlab/Simulink: Effect of Temperature

In this work, we study the method for determining the maximum of the minority carrier recombination velocity at the junction Sfmax, corresponding to the maximum power delivered by the photovoltaic generator. For this, we study the temperature influence on the behavior of the front white biased solar cell in steady state. By solving the continuity equation of excess minority carrier in the base, we have established the expressions of the photocurrent density, the recombination velocity on the back side of the base Sb, and the photovoltage. The photocurrent density and the photovoltage are plotted as a function of Sf, called, minority carrier recombination velocity at the junction surface, for different temperature values. The illuminated I-V characteristic curves of the solar cell are then derived. To better characterize the solar cell, we study the electrical power delivered by the base of the solar cell to the external charge circuit as either junction surface recombination velocity or photovoltage dependent. From the output power versus junction surface recombination velocity Sf, we have deduced an eigenvalue equation depending on junction recombination velocity. This equation allows to obtain the maximum junction recombination velocity Sfmax corresponding to the maximum power delivered by the photovoltaic generator, throughout simulink model. Finally, we deduce the conversion efficiency of the solar cell.

Irradiation Energy Effect on a Silicon Solar Cell: Maximum Power Point Determination

The aim of this study is to determinate the electrical parameters of a white biased silicon solar cell submitted to an irradiation energy of particles (protons, helium, electrons and heavy ions). A theoretical study of the influence of irradiation energy on the photocurrent density, the photovoltage, the maximum power, as well as the maximum efficiency of the solar cell is presented through a resolution of the continuity equation relative to excess minority carrier. Then the expressions of the photocurrent density Jph, the photovoltage Vph, and the excess minority carrier recombination velocity at the back side Sb are established dependent of irradiation parameters ∅p, Kl respectively irradiation flux and intensity. In this work, we propose a method for determining the recombination velocity of the excess minority carrier at the junction Sfmax corresponding to the maximum power point delivered by the photovoltaic generator under the influence of the irradiation. It is then obtained by calculating the derivative of the power with respect to the excess minority carrier recombination velocity Sf at the junction emitter-base. A transcendental equation solution is deduced as eigenvalue, leading to the junction recombination velocity of excess minority carrier and also yields the solar cell maximum conversion efficiency.

Determination of the Junction Recombination Velocity Initiating the Short Circuit Situation Sfsc of a Bifacial Silicon Solar Cell Irradiated Under Magnetic Field in Dynamic Frequency Regime

The object of this work, a study of the junction recombination velocity limiting the short circuit (Sfsc) of a silicon solar cell under magnetic field in the dynamic frequency regime is presented. From the continuity equation, the density of minority Charge carrier’s in the base and the photocurrent are determined. The study of this photocurrent, according to the junction recombination velocity, allows us to determine the junction recombination velocity limiting the short circuit. The photocurrent density is studied as a function of the junction recombination velocity for different modulation frequencies. From the variation profile of the photocurrent density as a function of the junction recombination velocity, a technique for determining junction recombination velocity initiating the short-circuit situation is presented.

Effect of junction quality on the performance of a silicon solar cell

In this work, a modeling study of the effect of the junction quality on the performance of a silicon solar cell is presented. Based on a one dimensional modeling of the solar cell, the continuity equation of excess minority carriers is solved with boundary conditions taking into account the intrinsic junction recombination velocity and led to analytical expressions of photocurrent density, photovoltage and electric power. The effect of the intrinsic junction recombination velocity or the solar cell junction quality on photocurrent, photovoltage and electric power, is exhibited and we determine the maximum electric power, the junction dynamic velocity at the maximum power point and the conversion efficiency according to the junction quality of the solar cell. From the electric power lost at the junction, we calculated the shunt resistance of the solar cell according to the junction quality.

Wavelength and Constant Magnetic field Dependence of the Steady-state Photoconductivity of a Bifacial Silicon Solar Cell

In this work, a theoretical study on the photoconductivity of a bifacial silicon solar cell under monochromatic illumination and constant magnetic field is presented. Analytical expression of the photoconductivity is established according to base depth, illumination wavelength, junction recombination velocity and magnetic field value. The photoconductivity profile versus wavelength shows two energy absorption peaks corresponding to specific wavelengths. Based on a linear model of the photoconductivity versus junction recombination velocity, in a given interval, we determine an equivalent capacitance which depends on both wavelength and magnetic field.

Bifacial Silicon Solar Cell Steady Photoconductivity under Constant Magnetic Field and Junction Recombination Velocity Effects

The paper reported a theoretical study on the photoconductivity of a bifacial silicon solar cell under polychromatic illumination and a constant magnetic field effect. By use of the continuity equation in the base of the solar cell maintained in a constant temperature at 300 K, an expression of the excess minority carriers’ density was determined according to the applied magnetic field, the base depth and the junction recombination velocity. From the expression of the minority carriers’ density, the photoconductivity of the solar cell was deduced and which allowed us to predict some recombination phenomena, the use of such solar cell in optoelectronics. The profile of the photoconductivity also permitted us to utilize a linear model in order to determine an electrical capacitance that varied with magnetic field.

Effect of Wavelength on the Photocurrent and Photovoltage of Vertical Parallel Silicon Solar Cells under Steady State Condition

The effect of wavelength on the photocurrent and photovoltage of a vertical parallel junction solar cell under steady state condition was theoretically analyzed. Based on the diffusion equation, the excess minority carrier's density is expressed; both photocurrent density and photovoltage determine the junction recombination velocity and the wavelengths. The excess minority carrier density, the photocurrent density, and the photovoltage were calculated and plotted. The objective of this work is to show the effects of solar cell junction recombination velocity and the wavelengths on these electrical parameters. We have shown the effect of wavelength on initiating the short-circuit (Sfsc) and limited the open circuit (Sfoc) of the solar cell through the junction recombination velocity. The determination of Sfoc obtained from the curve of photovoltage versus Sf, and the determination of Sfsc is through from the curve of the photocurrent density according to Sf. The improvement of the solar cells limits the recombination of the excess minority carrier's photogenerated. Parameters and the control of the technological process of manufacturing are significant during the conception of these devices. Several methods of characterization in static or quasi-static mode, as well as in transient state and dynamic frequency mode have been developed for the determination of one or several parameters (1, 2). In this regard, we resolve continuity equation about relative to excess minority carriers in the base.

Effect of junction recombination velocity of electrical parameters of a vertical parallel silicon solar cell under frequency modulation

This study investigates a theoretical study based on the determination of electrical parameters in solar cell junction vertical parallel silicon under polychromatic illumination and frequency modulation. From the excess minority carrier’s density in the solar cell, the photocurrent density and the photovoltage are derived. The route of the current voltage density (I = f(V)) that materializes the behavior of the generator; we have a model on the shunt resistance and the series resistance. The I–V method is used to determine electrical parameters such as resistance and shunt resistance or various junction recombination velocity. From their expressions, we study their pace according to Bode and Nyquist and then extend the study to other electrical parameter. The Bode diagrams of the diffusion capacitance are shown for different junction recombination velocity.

Effect of incidence angle on the electrical parameters of vertical parallel junction silicon solar cell under frequency domain

The effect of incidence angle on the electrical parameters of vertical parallel silicon solar cell under frequency domain was theoretically analyzed. Based on the diffusion-recombination equation, the expression of excess minority carrier density in the base was established according to the modulation frequency and the illumination incidence angle. The excess minority carrier density, the photocurrent density, the photo voltage, series resistance, shunt resistance, electric power and the space charge region capacitance were calculated and plotted. The objective of this work was to show the effects of solar cell modulation frequency and the illumination incidence angle on these electrical parameters, electric power and space charge region capacitance. Plots of solar cell’s electric power with the junction recombination velocity gave the maximum solar cell’s electric power; Pm. Influence of various parameters of incidence angles on the solar cell’s electric power was also studied.

A 3D Modelling of Solar Cell’s Electric Power under Real Operating Point

This work, based on the junction recombination velocity (Sfu) concept, is used to study the solar cell’s electric power at any real operating point. Using Sfu and the back side recombination velocity (Sbu) in a 3D modelling study, the continuity equation is resolved. We determined the photocurrent density, the photovoltage and the solar cell’s electric power which is a calibrated function of the junction recombination velocity (Sfu). Plots of solar cell’s electric power with the junction recombination velocity give the maximum solar cell’s electric power, Pm. Influence of various parameters such as grain size (g), grain boundaries recombination velocity (Sgb), wavelength (λ) and for different illumination modes on the solar cell’s electric power is studied.

Influence of Temperature on the Electrical Parameters of a Vertical Parallel Junction Silicon Solar Cell under Polychromatic Illumination in Steady State

This study presents a theoretical study of a vertical parallel junction solar cell under multispectral illumination in steady state. Based on the diffusion equation, the excess minority carrier's density is expressed and both photocurrent density and photovoltage are determined. For all these parameters we showed the effect of external temperature with respect to the operating point of the solar cell through the junction recombination velocity.

Illumination Level Effects on Macroscopic Parameters of a Bifacial Solar Cell

This study presents a method based on the experimental measurement of the short-circuit current (Icc) and the open circuit voltage (Vco) of the solar cell. It permits the determination of recombination parameters such as: diffusion length (L), back surface recombination velocity (Sb), intrinsic junction recombination velocity (Sjo), and macroscopic parameters in particular, the shunt and series resistances of a bifacial solar cell for various illumination levels (n). Illumination level effects on macroscopic parameters are highlighted.

Concept of Recombination Velocity Sfcc at the Junction of a Bifacial Silicon Solar Cell, in Steady State, Initiating the Short-Circuit Condition

The aim of this study is to present technics to determine the junction recombination velocity of a bifacial polycrystalline silicon solar cell under both, constant multispectral illumination and steady short-circuit condition.