¹V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine 45, prospect Nauky, 03680 Kyiv, Ukraine
²Memorial University of Newfoundland, St. John’s, NL, Canada E-mail: sach@isp.kiev.ua; viktorvlasiuk@gmail.com

Abstract. The key parameters of silicon solar cells with back contact and rear metallization (SC-BC), such as the short-circuit current, open-circuit voltage, and photoconversion efficiency are modeled theoretically. Among other recombination channels, the model accounts for the non-radiative Auger recombination assisted by the deep recombination center and recombination in the space-charge region. It has been ascertained that these mechanisms are important in the typical commercial SC-BC in the maximal-power regime. The theory has been developed for calculating the efficiency as a function of the SC-BC thickness. Experimental and theoretical data agree well between each other. In particular, the theory has been applied to model the SC-BC produced by SunPower Corp. Depending on the surface recombination velocity on the illuminated surface and on the total surface recombination velocity on the front and rear surfaces, two mechanisms determine the optimal SC-BC thickness, at which the output power reaches its maximal. The first mechanism dominates, when the efficiency exceeds 24% under the AM1.5 conditions and is related to an essential increase of photon mean free path in the textured silicon SC. The other mechanism, more pronounced in the SC-BC with the efficiency below 22%, imposes limitations on the optimal thickness due to the surface recombination on the front SC-BC surface.

Keywords: solar cells, photoconversion efficiency, silicon, optimal thickness, surface recombination.

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