The characterization of the performances of a PV cell is linked to intrinsic factors of this cell... more The characterization of the performances of a PV cell is linked to intrinsic factors of this cell. It is therefore important for us to identify the favorable or unfavorable conditions that affect the performance of PV cells. It is from this perspective that it seems judicious to us to study the simultaneous influence of the heating of the base and an external electric field on the performance of a PV cell under intense illumination of 50 suns. Two phenomena contribute to the heating of the base of a PV cell which is heating due to the transfer by conduction of solar radiation energy received by the surface of the PV cell and the heat generated inside the PV cell by various phenomena linked to the movement of photogenerated charged carriers. In this study, we take into account the heating linked to the movement of the charged carriers in the base. After a mathematical modeling of the PV cell considered, some hypotheses are formulated and the expressions of the electrical parameters are established as a function of the electric field and base temperature. Subsequently, we use numerical simulation to highlight the behavior of theses parameters as a function of temperature and of the intensity of the electric field. The results show that for any given temperature, the orientation of the electric field as considered in our work improves the performance of the PV cell while high temperatures degrade these performances. Furthermore, the analysis of the curves shows that the harmful effect of temperature on the performance of a PV cell is more accentuated at large values of electric field.
IOP Conference Series: Materials Science and Engineering, 2012
In this paper we present a technique for determining the optimum junction recombination velocity ... more 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.
At the University of Ouagadougou, the largest university in Burkina Faso, the percentage of femal... more At the University of Ouagadougou, the largest university in Burkina Faso, the percentage of female student enrollment in the Exact and Applied Sciences Unit was 5.1% (for all the levels) from 2006 to 2009-this rate was 2.3% for physics. For the same period, 22 women out of 455 students (4.8%) were enrolled in PhD (all the fields of the Exact and Applied Sciences Unit) and three women out of 180 students (1.7%) registered in physics PhD. During the 3rd IUPAP International Conference on Women in Physics in 2008, the Burkina Faso Working Group proposed some strategies to attract more women to physics and all the sciences. Some actions were initiated at the University of Ouagadougou as well as in secondary schools. These actions and the feedback of female students are presented.
Although 52% of Burkina Faso's population is women, boys receive preference in schooling. In 2006... more Although 52% of Burkina Faso's population is women, boys receive preference in schooling. In 2006, only about 10% of the secondary school pupils were girls. At the University of Ouagadougou in 2000-2005 one quarter of the students were women, but just 5% of students in the sciences were women. This rate is dramatically lower in physics, both for the students (less than 1%) and for the teachers (only two women). This condition can be explained by religious and cultural considerations, financial and economic reasons, social pressure (mathematics, physics, and technology are dedicated to men), and future prospects for scientists in Burkina Faso. Some strategies to better feminize physics (and the sciences) in Burkina Faso are presented.
Research Journal of Applied Sciences, Engineering and Technology, 2013
In this study, we present the study of the photo-thermal response of a monofacial silicon solar c... more In this study, we present the study of the photo-thermal response of a monofacial silicon solar cell illuminated by a multispectral light for a constant modulated frequency. Solving the continuity equation for minority carriers in the base of the solar cell resulting in the terms of the heat equations in the presence of an optical source. The density of minority carriers in excess, the amplitude of the variation of temperature and the heat flux density were studied and analyzed for different angular pulses and rates of recombination at the junction. Representations of Nyquist and Bode plots of the thermal dynamic impedance resulted in an equivalent electrical circuit of the photocell.
For silicon solar cells simulation studies, one dimensional (1D), two dimensional 2D) and t h... more 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 ...
Studies on concentrated light influence do not take into account the effect of the heating and th... more Studies on concentrated light influence do not take into account the effect of the heating and this proves to be harmful on photovoltaic parameters. The main purpose of this work is to study the effects of light concentration and the heating caused by this concentration on intrinsic properties and carrier density profile. A thermal model of the PV cell is proposed. By applying the power balance at the steady-state, the PV cell thermal equation is determined. The resolution of this equation leads to temperature profile which shows a rapid increase with light concentration. The mobility n and diffusion n D coefficients of electrons increase to reach their maxima, respectively 2 1 1 max () 1895,31 n cm V s at C=6,77 Suns where temperature is T=430,92 K and 21 max () 76,55. n D cm s at C= 12,59 Suns where temperature is T=508,24; before decreasing. However, for the holes these parameters decrease slowly with concentration increase. Silicon gap energy decreases while electrons intrinsic density increases with increasing concentration. The variations of these parameters are explained on one hand by their dependence on temperature but also by temperature profile with concentration. An electrical model of the PV cell under variable concentration is also proposed and from which the carrier's density is determined. It emerges that the carrier density increases significantly with concentration ratio. This fact is explained by the photo-generation increase with concentration. And also, by thermal generation increase linked to temperature increases with concentration increase. Results also show that carriers density is greater in the rear side compared to the zone near the junction in opposite to authors who did not take into account temperature effect and who showed that carriers density is greater at the illuminated face.
A three-dimensional approach to the effect of magnetic field incidence angle on electrical power ... more A three-dimensional approach to the effect of magnetic field incidence angle on electrical power and conversion efficiency is performed on a front-illuminated polycrystalline silicon bifacial solar cell. A solution of the continuity equation allowed us to present the equations of photocurrent density, photovoltage and electric power. The influence of the angle of incidence of the magnetic field on the photocurrent density, the photovoltage and the electric power has been studied. The curves of electrical power versus dynamic junction velocity were used to extract the values of maximum electrical power and dynamic junction velocity and to calculate those of conversion efficiency. From this study, it is found that the conversion efficiency values increase with the angle of incidence of the magnetic field.
The aim of this work is to study the behaviour of a silicon solar cell under the irradiation of d... more The aim of this work is to study the behaviour of a silicon solar cell under the irradiation of different fluences of high-energy proton radiation (10 MeV) and under constant multispectral illumination. Many theoretical et experimental studies of the effect of irradiation (proton, gamma, electron, etc.) on solar cells have been carried out. These studies point out the effect of irradiation on the behaviour of the solar cell electrical parameters but do not explain the causes of these effects. In our study, we explain fundamentally the causes of the effects of the irradiation on the solar cells. Taking into account the empirical formula of diffusion length under the effect of high-energy particle irradiation, we established new expressions of continuity equation, photocurrent density, photovoltage, and dynamic junction velocity. Based on these equations, we studied the behaviour of some electronic and electrical parameters under proton radiation. Theoretical results showed that the d...
Advances in Science and Technology Research Journal, 2017
This work put in evidence, magnetic field effect the electrical parameters of a silicon solar cel... more This work put in evidence, magnetic field effect the electrical parameters of a silicon solar cell illuminated by an intense light concentration: external load electric power, conversion efficiency, fill factor, external optimal charge load. Due to the high photogeneration of a carrier in intense light illumination mode, in addition of magnetic field, we took into account the carrier gradient electric field in the base of the solar cell. Taking into account this electric field and the applied magnetic field in our model led to new analytical expressions of the continuity equation, the photocurrent and the photovoltage. In this work, we used the electric power curves versus junction dynamic velocity (S j) to determine, according to magnetic field, the maximum electric power P elmax and we calculate the solar cell conversion efficiency (η). We also used the J-V characteristics to determine the solar cell short circuit density current (J cc) and the open circuit voltage (V co) under magnetic field and we calculate the fill factor (FF). Finally, we used simultaneously the J-V characteristics and equipower curves to determine the optimal external load resistance. The results of this study have showed that the maximum electric power and the conversion efficiency are higher than those of monofacial and bifacial silicon solar cells illuminated by conventional light but they decreased with the increase of magnetic field.
Global Journal of Science Frontier Research, Sep 22, 2012
In this article, we are discussing the Gauss's law used to determine the width emitter extension ... more In this article, we are discussing the Gauss's law used to determine the width emitter extension region of the solar cell operating in open circuit condition. Taking into account the grain size (g), the grain boundary recombination velocity (Sgb) and the emitter doping density (Nemitter), the Gaussian Law helped us to calculate the width emitter extension region of the solar cell operating in open circuit condition. To determine the width emitter extension region, we first showed that grain size (g), grain boundary recombination velociy (Sgb) are oppesite effects and concluded that best solar cells are characterized by low junction extension region width observed only with high grain size (g) and low grain boundary recombination velocity (Sgb).
The solar cell is assumed to be under light concentration (C=50 Suns) which leads us to take into... more The solar cell is assumed to be under light concentration (C=50 Suns) which leads us to take into consideration the electric field induced by electrons concentration gradient. We also take into consideration temperature influence on electron and hole diffusion parameters, on carrier generation rate, on carrier intrinsic concentration and on silicon energy gap. It emerges from results analysis that increase in temperature leads to decrease of open-circuit voltage and the photovoltaic parameters at the maximum power point (MPP) such as electric power, photo-voltage and photocurrent with however a slight increase of short-circuit photocurrent density. It also appears that temperature has a double effect on electrical parameters. The temperature dynamic effect which is characterized by parameters variations linked to operating point displacement caused by temperature variations. And the temperature proper effect which is characterized by parameters variation with temperature at a given ...
Performances of a solar cell are significantly influenced by the heating of the base. Two phenome... more Performances of a solar cell are significantly influenced by the heating of the base. Two phenomena contribute to the heating of the base of a PV cell: the heat due to the transfer by conduction of the solar energy radiation received by the surface of the PV cell and the heat generated inside the solar cell by various phenomena related to the movement of photogenerated electrons and holes. Thus, even if the increase of the quantity of carriers leads to improve the PV cell electrical parameters, this phenomenon also leads to the increase of some internal phenomena like thermalization, carriers braking and the carriers collisions which are sources of heating of the base of the solar cell Indeed, electrical parameters (photocurrent, photovoltage, electric power) are physical quantities related to the movement of charge carriers and also to the illumination mode, this means that changing of electrical parameters during the operation of the PV cell leads to a variation of the temperature...
Abstract This work investigated the response of an illuminated polysilicon PV cell under AM radio... more Abstract This work investigated the response of an illuminated polysilicon PV cell under AM radio waves. Using a 3 D analysis, the equations which describe the movement of excess electrons and their space and time behavior were solved in order to first find the density of the excess electrons and to subsequently derive the current density and the voltage. The effect of the amplitude of the electromagnetic field (EMF) on the current density and the voltage were studied by varying the distance between the PV cell and an AM radio antenna. The combination of the two characteristics, i.e. current density–voltage and Power–Voltageallowed the computation of the efficiency, the fill factor and the parasitic resistances ( R s , R s h ) of the electrical equivalent circuit of the PV cell. The study showed that from infinite distance to 50 m, corresponding to the Fraunhofer zone, the conversion efficiency increases slightly by about 1% and the fill factor decreases within the same order of magnitude. On the other hand, the series and shunt resistances fall considerably down by about 14% and 13% respectively. The power output curves versus the junction dynamic velocity which allow the computation of the shunt resistance, are used to highlight the impact of the electromagnetic field (EMF) on the operation of the cell. Between an infinite distance and 50 m, the results indicate a very high drop of the shunt resistance (from 64,280 Ω cm 2 to 11 Ω cm 2). Overall, one can conclude that the presence of EMF adversely affects the operation of polysilicon PV cell considering the high drop of the shunt resistance.
In earlier studies, we have shown theoretically and experimentally that magnetic fields (MFs) hav... more In earlier studies, we have shown theoretically and experimentally that magnetic fields (MFs) have negative impact on silicon PV module (photovoltaic module). A noticeable decline in photocurrent with a slight increase in photovoltage was observed. Also, how those fields affected other key module’s parameters was also studied. These studies concluded that an increase in the magnitude of the MF resulted in the decrease of the efficiency of the silicon PV module. The previous experimental studies assumed that the MF vector formed zero angle of inclination with respect to the photosensitive face of the module. They did not factor in any effect that could be observed when the field vector is inclined. The present experimental work is an attempt to fill that gap. The characteristic curves of the PV module were plotted in the same system of axis for different values of the inclination angle of the MF vector. Correspondingly, the characteristic values ( , , , , and ) of the PV module were ...
The aim of this work is to investigate, with a three-dimensional steady-state approach, the effec... more The aim of this work is to investigate, with a three-dimensional steady-state approach, the effect of the incidence angle of a magnetic field on the performance of a polycrystalline silicon solar cell under multispectral illumination. The magneto-transport and continuity equations of excess minority carriers are solved to find the expression of the density of excess minority carriers and the related electrical parameters, such as the photocurrent density, the photovoltage and the electric power, of a grain of the polycrystalline silicon solar cell. The influence of the incidence angle of the magnetic field on the diffusion coefficient, the short-circuit photocurrent density, the open-circuit photovoltage and the electric power-photovoltage is studied. Then, the curves of the electric power-photovoltage is used to find the maximum electric power allowing to calculate, according to the incidence angle of the magnetic field, the fill factor and the conversion efficiency. The study has shown that the increase of the incidence angle of the magnetic field from 0 rad to π/2 rad, can reduce the degradation of the performance of solar cells.
In this work, a modeling study of the effect of the junction quality on the performance of a sili... more 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.
The characterization of the performances of a PV cell is linked to intrinsic factors of this cell... more The characterization of the performances of a PV cell is linked to intrinsic factors of this cell. It is therefore important for us to identify the favorable or unfavorable conditions that affect the performance of PV cells. It is from this perspective that it seems judicious to us to study the simultaneous influence of the heating of the base and an external electric field on the performance of a PV cell under intense illumination of 50 suns. Two phenomena contribute to the heating of the base of a PV cell which is heating due to the transfer by conduction of solar radiation energy received by the surface of the PV cell and the heat generated inside the PV cell by various phenomena linked to the movement of photogenerated charged carriers. In this study, we take into account the heating linked to the movement of the charged carriers in the base. After a mathematical modeling of the PV cell considered, some hypotheses are formulated and the expressions of the electrical parameters are established as a function of the electric field and base temperature. Subsequently, we use numerical simulation to highlight the behavior of theses parameters as a function of temperature and of the intensity of the electric field. The results show that for any given temperature, the orientation of the electric field as considered in our work improves the performance of the PV cell while high temperatures degrade these performances. Furthermore, the analysis of the curves shows that the harmful effect of temperature on the performance of a PV cell is more accentuated at large values of electric field.
IOP Conference Series: Materials Science and Engineering, 2012
In this paper we present a technique for determining the optimum junction recombination velocity ... more 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.
At the University of Ouagadougou, the largest university in Burkina Faso, the percentage of femal... more At the University of Ouagadougou, the largest university in Burkina Faso, the percentage of female student enrollment in the Exact and Applied Sciences Unit was 5.1% (for all the levels) from 2006 to 2009-this rate was 2.3% for physics. For the same period, 22 women out of 455 students (4.8%) were enrolled in PhD (all the fields of the Exact and Applied Sciences Unit) and three women out of 180 students (1.7%) registered in physics PhD. During the 3rd IUPAP International Conference on Women in Physics in 2008, the Burkina Faso Working Group proposed some strategies to attract more women to physics and all the sciences. Some actions were initiated at the University of Ouagadougou as well as in secondary schools. These actions and the feedback of female students are presented.
Although 52% of Burkina Faso's population is women, boys receive preference in schooling. In 2006... more Although 52% of Burkina Faso's population is women, boys receive preference in schooling. In 2006, only about 10% of the secondary school pupils were girls. At the University of Ouagadougou in 2000-2005 one quarter of the students were women, but just 5% of students in the sciences were women. This rate is dramatically lower in physics, both for the students (less than 1%) and for the teachers (only two women). This condition can be explained by religious and cultural considerations, financial and economic reasons, social pressure (mathematics, physics, and technology are dedicated to men), and future prospects for scientists in Burkina Faso. Some strategies to better feminize physics (and the sciences) in Burkina Faso are presented.
Research Journal of Applied Sciences, Engineering and Technology, 2013
In this study, we present the study of the photo-thermal response of a monofacial silicon solar c... more In this study, we present the study of the photo-thermal response of a monofacial silicon solar cell illuminated by a multispectral light for a constant modulated frequency. Solving the continuity equation for minority carriers in the base of the solar cell resulting in the terms of the heat equations in the presence of an optical source. The density of minority carriers in excess, the amplitude of the variation of temperature and the heat flux density were studied and analyzed for different angular pulses and rates of recombination at the junction. Representations of Nyquist and Bode plots of the thermal dynamic impedance resulted in an equivalent electrical circuit of the photocell.
For silicon solar cells simulation studies, one dimensional (1D), two dimensional 2D) and t h... more 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 ...
Studies on concentrated light influence do not take into account the effect of the heating and th... more Studies on concentrated light influence do not take into account the effect of the heating and this proves to be harmful on photovoltaic parameters. The main purpose of this work is to study the effects of light concentration and the heating caused by this concentration on intrinsic properties and carrier density profile. A thermal model of the PV cell is proposed. By applying the power balance at the steady-state, the PV cell thermal equation is determined. The resolution of this equation leads to temperature profile which shows a rapid increase with light concentration. The mobility n and diffusion n D coefficients of electrons increase to reach their maxima, respectively 2 1 1 max () 1895,31 n cm V s at C=6,77 Suns where temperature is T=430,92 K and 21 max () 76,55. n D cm s at C= 12,59 Suns where temperature is T=508,24; before decreasing. However, for the holes these parameters decrease slowly with concentration increase. Silicon gap energy decreases while electrons intrinsic density increases with increasing concentration. The variations of these parameters are explained on one hand by their dependence on temperature but also by temperature profile with concentration. An electrical model of the PV cell under variable concentration is also proposed and from which the carrier's density is determined. It emerges that the carrier density increases significantly with concentration ratio. This fact is explained by the photo-generation increase with concentration. And also, by thermal generation increase linked to temperature increases with concentration increase. Results also show that carriers density is greater in the rear side compared to the zone near the junction in opposite to authors who did not take into account temperature effect and who showed that carriers density is greater at the illuminated face.
A three-dimensional approach to the effect of magnetic field incidence angle on electrical power ... more A three-dimensional approach to the effect of magnetic field incidence angle on electrical power and conversion efficiency is performed on a front-illuminated polycrystalline silicon bifacial solar cell. A solution of the continuity equation allowed us to present the equations of photocurrent density, photovoltage and electric power. The influence of the angle of incidence of the magnetic field on the photocurrent density, the photovoltage and the electric power has been studied. The curves of electrical power versus dynamic junction velocity were used to extract the values of maximum electrical power and dynamic junction velocity and to calculate those of conversion efficiency. From this study, it is found that the conversion efficiency values increase with the angle of incidence of the magnetic field.
The aim of this work is to study the behaviour of a silicon solar cell under the irradiation of d... more The aim of this work is to study the behaviour of a silicon solar cell under the irradiation of different fluences of high-energy proton radiation (10 MeV) and under constant multispectral illumination. Many theoretical et experimental studies of the effect of irradiation (proton, gamma, electron, etc.) on solar cells have been carried out. These studies point out the effect of irradiation on the behaviour of the solar cell electrical parameters but do not explain the causes of these effects. In our study, we explain fundamentally the causes of the effects of the irradiation on the solar cells. Taking into account the empirical formula of diffusion length under the effect of high-energy particle irradiation, we established new expressions of continuity equation, photocurrent density, photovoltage, and dynamic junction velocity. Based on these equations, we studied the behaviour of some electronic and electrical parameters under proton radiation. Theoretical results showed that the d...
Advances in Science and Technology Research Journal, 2017
This work put in evidence, magnetic field effect the electrical parameters of a silicon solar cel... more This work put in evidence, magnetic field effect the electrical parameters of a silicon solar cell illuminated by an intense light concentration: external load electric power, conversion efficiency, fill factor, external optimal charge load. Due to the high photogeneration of a carrier in intense light illumination mode, in addition of magnetic field, we took into account the carrier gradient electric field in the base of the solar cell. Taking into account this electric field and the applied magnetic field in our model led to new analytical expressions of the continuity equation, the photocurrent and the photovoltage. In this work, we used the electric power curves versus junction dynamic velocity (S j) to determine, according to magnetic field, the maximum electric power P elmax and we calculate the solar cell conversion efficiency (η). We also used the J-V characteristics to determine the solar cell short circuit density current (J cc) and the open circuit voltage (V co) under magnetic field and we calculate the fill factor (FF). Finally, we used simultaneously the J-V characteristics and equipower curves to determine the optimal external load resistance. The results of this study have showed that the maximum electric power and the conversion efficiency are higher than those of monofacial and bifacial silicon solar cells illuminated by conventional light but they decreased with the increase of magnetic field.
Global Journal of Science Frontier Research, Sep 22, 2012
In this article, we are discussing the Gauss's law used to determine the width emitter extension ... more In this article, we are discussing the Gauss's law used to determine the width emitter extension region of the solar cell operating in open circuit condition. Taking into account the grain size (g), the grain boundary recombination velocity (Sgb) and the emitter doping density (Nemitter), the Gaussian Law helped us to calculate the width emitter extension region of the solar cell operating in open circuit condition. To determine the width emitter extension region, we first showed that grain size (g), grain boundary recombination velociy (Sgb) are oppesite effects and concluded that best solar cells are characterized by low junction extension region width observed only with high grain size (g) and low grain boundary recombination velocity (Sgb).
The solar cell is assumed to be under light concentration (C=50 Suns) which leads us to take into... more The solar cell is assumed to be under light concentration (C=50 Suns) which leads us to take into consideration the electric field induced by electrons concentration gradient. We also take into consideration temperature influence on electron and hole diffusion parameters, on carrier generation rate, on carrier intrinsic concentration and on silicon energy gap. It emerges from results analysis that increase in temperature leads to decrease of open-circuit voltage and the photovoltaic parameters at the maximum power point (MPP) such as electric power, photo-voltage and photocurrent with however a slight increase of short-circuit photocurrent density. It also appears that temperature has a double effect on electrical parameters. The temperature dynamic effect which is characterized by parameters variations linked to operating point displacement caused by temperature variations. And the temperature proper effect which is characterized by parameters variation with temperature at a given ...
Performances of a solar cell are significantly influenced by the heating of the base. Two phenome... more Performances of a solar cell are significantly influenced by the heating of the base. Two phenomena contribute to the heating of the base of a PV cell: the heat due to the transfer by conduction of the solar energy radiation received by the surface of the PV cell and the heat generated inside the solar cell by various phenomena related to the movement of photogenerated electrons and holes. Thus, even if the increase of the quantity of carriers leads to improve the PV cell electrical parameters, this phenomenon also leads to the increase of some internal phenomena like thermalization, carriers braking and the carriers collisions which are sources of heating of the base of the solar cell Indeed, electrical parameters (photocurrent, photovoltage, electric power) are physical quantities related to the movement of charge carriers and also to the illumination mode, this means that changing of electrical parameters during the operation of the PV cell leads to a variation of the temperature...
Abstract This work investigated the response of an illuminated polysilicon PV cell under AM radio... more Abstract This work investigated the response of an illuminated polysilicon PV cell under AM radio waves. Using a 3 D analysis, the equations which describe the movement of excess electrons and their space and time behavior were solved in order to first find the density of the excess electrons and to subsequently derive the current density and the voltage. The effect of the amplitude of the electromagnetic field (EMF) on the current density and the voltage were studied by varying the distance between the PV cell and an AM radio antenna. The combination of the two characteristics, i.e. current density–voltage and Power–Voltageallowed the computation of the efficiency, the fill factor and the parasitic resistances ( R s , R s h ) of the electrical equivalent circuit of the PV cell. The study showed that from infinite distance to 50 m, corresponding to the Fraunhofer zone, the conversion efficiency increases slightly by about 1% and the fill factor decreases within the same order of magnitude. On the other hand, the series and shunt resistances fall considerably down by about 14% and 13% respectively. The power output curves versus the junction dynamic velocity which allow the computation of the shunt resistance, are used to highlight the impact of the electromagnetic field (EMF) on the operation of the cell. Between an infinite distance and 50 m, the results indicate a very high drop of the shunt resistance (from 64,280 Ω cm 2 to 11 Ω cm 2). Overall, one can conclude that the presence of EMF adversely affects the operation of polysilicon PV cell considering the high drop of the shunt resistance.
In earlier studies, we have shown theoretically and experimentally that magnetic fields (MFs) hav... more In earlier studies, we have shown theoretically and experimentally that magnetic fields (MFs) have negative impact on silicon PV module (photovoltaic module). A noticeable decline in photocurrent with a slight increase in photovoltage was observed. Also, how those fields affected other key module’s parameters was also studied. These studies concluded that an increase in the magnitude of the MF resulted in the decrease of the efficiency of the silicon PV module. The previous experimental studies assumed that the MF vector formed zero angle of inclination with respect to the photosensitive face of the module. They did not factor in any effect that could be observed when the field vector is inclined. The present experimental work is an attempt to fill that gap. The characteristic curves of the PV module were plotted in the same system of axis for different values of the inclination angle of the MF vector. Correspondingly, the characteristic values ( , , , , and ) of the PV module were ...
The aim of this work is to investigate, with a three-dimensional steady-state approach, the effec... more The aim of this work is to investigate, with a three-dimensional steady-state approach, the effect of the incidence angle of a magnetic field on the performance of a polycrystalline silicon solar cell under multispectral illumination. The magneto-transport and continuity equations of excess minority carriers are solved to find the expression of the density of excess minority carriers and the related electrical parameters, such as the photocurrent density, the photovoltage and the electric power, of a grain of the polycrystalline silicon solar cell. The influence of the incidence angle of the magnetic field on the diffusion coefficient, the short-circuit photocurrent density, the open-circuit photovoltage and the electric power-photovoltage is studied. Then, the curves of the electric power-photovoltage is used to find the maximum electric power allowing to calculate, according to the incidence angle of the magnetic field, the fill factor and the conversion efficiency. The study has shown that the increase of the incidence angle of the magnetic field from 0 rad to π/2 rad, can reduce the degradation of the performance of solar cells.
In this work, a modeling study of the effect of the junction quality on the performance of a sili... more 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.
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