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Energy and Power Engineering 2020年第10期12卷 543-554页

作者： amadou Mar Ndiaye Sega Gueye Ousmane Sow Gora Diop amadou mamour ba Mamadou Lamine ba Ibrahima Diatta Lemrabott Habiboullah Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal University Institute of Technology University of Thiès Thiès Senegal Ecole Supérieure Polytechnique de Nouakchott Département Génie Electrique Nouackchott Mauritanie

This work deals with determining the optimum thickness of the base of an n+/p/p+ silicon solar cell under monochromatic illumination in frequency modulation. The continuity equation for the density of minority carriers generated in the base, by a monochromatic wavelength illumination (λ), with boundary conditions that impose recombination velocities (Sf) and (Sb) respectively at the junction and back surface, is resolved. The ac photocurrent is deduced and studied according to the recombination velocity at the junction, to extract the mathematical expressions of recombination velocity (Sb). By the graphic technique of comparing the two expressions obtained, depending on the thickness (H) of the base, for each frequency, the optimum thickness (Hopt) is obtained. It is then modeled according to the frequency, at the long wavelengths of the incident light. Thus, Hopt decreases due to the low relaxation time of minority carriers, when the frequency of modulation of incident light increases.

关键词： Silicon Solar Cell Modulation Frequency Recombination Velocity base Thickness Wavelength

n+-p-p+Silicon Solar Cell base Optimum Thickness Determination under Magnetic Field

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Journal of Electromagnetic Analysis and Applications 2020年第7期12卷 103-113页

作者： Cheikh Thiaw Mamadou Lamine ba mamour amadou ba Gora Diop Ibrahima Diatta Mor Ndiaye Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal

base optimum thickness is determined for a front illuminated bifacial silicon solar cell n+-p-p+ under magnetic field. From the magneto transport equation relative to excess minority carriers in the base, with specific boundary conditions, the photocurrent is obtained. From this result the expressions of the carrier’s recombination velocity at the back surface are deducted. These new expressions of recombination velocity are plotted according to the depth of the base, to deduce the optimum thickness, which will allow the production, of a high short-circuit photocurrent. Calibration relationships of optimum thickness versus magnetic field were presented according to study ranges. It is found that, applied magnetic field imposes a weak thickness material for solar cell manufacturing leading to high short-circuit current.

关键词： Silicon Solar Cell Magnetotransport Surface Recombination Velocity base Thickness

Diffusion Coefficient at Resonance Frequency as Applied to n+/p/p+ Silicon Solar Cell Optimum base Thickness Determination

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Journal of Electromagnetic Analysis and Applications 2020年第10期12卷 145-158页

作者： amadou Mar Ndiaye Sega Gueye Mame Faty Mbaye Fall Gora Diop amadou mamour ba Mamadou Lamine ba Ibrahima Diatta Lemrabott Habiboullah Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal Ecole Polytechnique de Thiès Thiès Sénégal Département Génie Electrique Ecole Supérieure Polytechnique de Nouakchott Nouakchott Mauritanie

The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial development for a low cost. In this work, an n+/p/p+ crystalline silicon solar cell is studied under monochromatic illumination in modulation and placed in a constant magnetic field. The minority carriers’ diffusion coefficient (D(ω, B), in the (p) base leads to maximum values (Dmax) at resonance frequencies (ωr). These values are used in expressions of AC minority carriers recombination velocity (Sb(Dmax, H)) in the rear of the base, to extract the optimum thickness while solar cell is subjected to these specific conditions. Optimum thickness modelling relationships, depending respectively on Dmax, ωr and B, are then established, and will be data for industrial development of low-cost solar cells for specific use.

关键词： Silicon Solar Cell Resonance Frequency Magnetic Field Recombination Velocity base Thickness

back Surface Recombination Velocity Dependent of Absorption Coefficient as Applied to Determine base Optimum Thickness of an n+/p/p+ Silicon Solar Cell

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Energy and Power Engineering 2020年第7期12卷 445-458页

作者： Meimouna Mint Sidi Dede Mamadou Lamine ba mamour amadou ba Mor Ndiaye Sega Gueye El Hadj Sow Ibrahima Diatta Masse Samba Diop Mamadou Wade Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal Ecole Polytechnique de Thiès (EPT) Thiès Senegal

The monochromatic absorption coefficient of silicon, inducing the light penetration depth into the base of the solar cell, is used to determine the optimum thickness necessary for the production of a large photocurrent. The absorption-generation-diffusion and recombination (bulk and surface) phenomena are taken into account in the excess minority carrier continuity equation. The solution of this equation gives the photocurrent according to absorption and electronic parameters. Then from the obtained short circuit photocurrent expression, excess minority carrier back surface recombination velocity is determined, function of the monochromatic absorption coefficient at a given wavelength. This latter plotted versus base thickness yields the optimum thickness of an n+-p-p+ solar cell, for each wavelength, which is in the range close to the energy band gap of the silicon material. This study provides a tool for improvement solar cell manufacture processes, through the mathematical relationship obtained from the thickness limit according to the absorption coefficient that allows base width optimization.

关键词： Silicon Solar Cell Absorption Coefficient back Surface Recombination Optimum Thickness

Influence of Both Magnetic Field and Temperature on Silicon Solar Cell base Optimum Thickness Determination

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Journal of Modern Physics 2019年第13期10卷 1596-1605页

作者： Nouh Mohamed Moctar Ould Mohamed Ousmane Sow Sega Gueye Youssou Traore Ibrahima Diatta Amary Thiam mamour amadou ba Richard Mane Ibrahima Ly Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal University Institute of Technology University of Thiès Thiès Sénégal Ecole Polytechnique de Thiès Thiès Sénégal

The minority carrier’s recombination velocity at the junction and at the back surface is used for the modeling and determination of the optimum thickness of the base of a silicon solar cell in the static regime, under magnetic field and temperature influence. This study takes into account the Umklapp process and the Lorentz effect on the minority carriers photogenerated in the base.

关键词： Silicon Solar Cell Diffusion Coefficient Surface Recombination Velocity Optimum base Thickness Lorentz and Umklapp Processes

A.C. Recombination Velocity as Applied to Determine n+/p/p+ Silicon Solar Cell baseOptimum Thickness

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Report of a New Case of Interlocking Heads in a Breech-Vertex Twin Delivery: A Conversation with My Residents

Energy and Power Engineering（能源与动力工程） 2020年第10期

作者： amadou Mar Ndiaye Sega Gueye Ousmane Sow Gora Diop amadou mamour ba Mamadou Lamine ba Ibrahima Diatta Lemrabott Habiboullah Gregoire Sissoko

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Open Journal of Obstetrics and Gynecology 2021年第1期11卷 40-47页

作者： mamour Gueye Mouhamadou Wade Aissatou Mbodji Mame Diarra Ndiaye Ndiémé Mbaye Mor Talla Ndiaye Rahadat Ibrahim amadou Lamine Cisse Aliou Djiby Dia Aliou Cisse Moussa Diallo Omar Gassama Ousmane Thiam Magatte Mbaye Philippe Senghor Health Center Cheikh Anta Diop University Dakar Senegal

“Locked twins” is a rare event occurring in about 1 in every 1000 twin births. A 21-year-old primigravida with a 31-week twin pregnancy was admitted for delivery. The head of the first twin was locked to the chin of the second twin at the top of the symphysis pubis. Caesarean section was performed allowing the delivery of both dead twins. Twins gestations with first twin in the breech presentation raise index of suspicion of potential locked twin. However, management of such situation is controversial with most authors and colleges recommending caesarean section to avoid interlocking heads. We report another rare case of interlocking heads and bring up the topic about management of breech-first twin deliveries.

关键词： Interlocking Heads Breech Presentation Twins Recommendations

Report of a New Case of Interlocking Heads in a Breech-Vertex Twin Delivery: A Conversation with My Residents

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