Back Illuminated N/P/P⁺ Bifacial Silicon Solar Cell under Modulated Short-Wavelength: Determination of Base Optimum Thickness

Mamadou Sall¹, Dianguina Diarisso², Mame Faty Mbaye Fall³, Gora Diop¹, Mor Ndiaye¹, Khady Loum³, Gregoire Sissoko^1*

¹Laboratory of Semiconductors and Solar Energy, Physics Department, Faculty of Science and Technology, Cheikh Anta Diop University, Dakar, Senegal.
²University Institute of Technology, University of Thiès, Thiès, Sénégal.
³Ecole Polytechnique de Thiès, Thiès, Sénégal.

DOI: 10.4236/epe.2021.135014                

Abstract

A bifacial silicon solar cell under monochromatic illumination in frequency modulation by the rear side is being studied for the optimization of base thickness. The density of photogenerated carriers in the base is obtained by resolution of the continuity equation, with the help of boundary conditions at the junction surface (n⁺/p) and the rear face (p/p⁺) of the base. For a short wavelength corresponding to a high absorption coefficient, the AC photocurrent density is calculated and represented according to the excess minority carrier’s recombination velocity at the junction, for different modulation frequency values. The expression of the AC recombination velocity of excess minority carriers at the rear surface of the base of the solar cell is then deduced, depending on both, the absorption coefficient of the silicon material and the thickness of the base. Compared to the intrinsic AC recombination velocity, the optimal thickness is extracted and modeled in a mathematical relationship, as a decreasing function of the modulated frequency of back illumination. Thus under these operating conditions, a maximum short-circuit photocurrent is obtained and a low-cost bifacial solar cell can be achieved by reducing material (Si) to elaborate the base thickness.

Keywords

Bifacial Silicon Solar Cell, AC Recombination Velocity-Base Thickness, Short-Wavelength

Conflicts of Interest

The authors declare no conflicts of interest regarding the publication of this paper.

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