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Computational Investigation of Interface Defects, Doping, and Emitter Thickness Effects in Front-and-Rear Illuminated Bifacial Heterojunction Solar Cells Using COMSOL Multiphysics

Author(s): Wafa Bakhat 1*, Asma Benchiheb 2,3, Hamza Lidjici4, Fatima Bakhat5

Published In : International Journal of Electrical and Electronics Research (IJEER)        Volume 14, Issue 3

Publisher : FOREX Publication

Published : 30 September 2026

e-ISSN : 2347-470X

Page(s) : 759-770

DOI: https://doi.org/10.37391/IJEER.140310

Abstract

Bifacial silicon heterojunction (HJ) solar cells have attracted considerable attention due to their high efficiency and capability to utilize illumination from both front and rear sides. In this work, a bifacial HJ solar cell with the structure IMAI/n-a-Si:H/c-Si/p-a-Si:H/ITO is numerically investigated using COMSOL Multiphysics. The device performance is analyzed under front-side, rear-side, and simultaneous bifacial illumination by considering the effects of interface-trap density, donor concentration, and emitter thickness of the n-type amorphous silicon layer. An asymmetric interface-trap configuration is adopted, with 1010(cm-2) at the n-a-Si:H/c-Si interface and 109(cm-2) at the c-Si/p-a-Si:H interface. Based on the investigated parameter ranges, a donor concentration of 5.1020(cm-3) is selected as the reference value, while an emitter thickness of 5 nm provides the best photovoltaic performance within the investigated thickness range. Under the selected parameter set, the simulated device exhibits conversion efficiencies of 26.6%, 20.09%, and 27% under front-side, rear-side, and simultaneous bifacial illumination, respectively. The rear-to-front efficiency ratio is 75.5%, indicating a pronounced front–rear asymmetry. The results indicate that the front-side photovoltaic response remains higher than the rear-side response, which is consistent with the asymmetric interface conditions and the resulting non-uniform recombination and carrier-transport behavior across the device structure. Overall, the findings highlight the importance of interface engineering and appropriate selection of emitter properties in controlling the photovoltaic performance of bifacial heterojunction solar cells.

Keywords: Bifacial HJ Solar Cell, Heterojunction, Interface-Trap Density, Ratio for Front and Rear Asymmetry, COMSOL Multiphysics.




Wafa Bakhat , LMAVER Laboratory for Renewable Energy Applications and Valorization, University of Laghouat, Algeria, and the Laboratory of Applied Sciences and Didactics, Higher Normal School of Laghouat, Algeria; Email: w.bakhat@lagh-univ.dz

Asma Benchiheb , Microsystems and Instrumentation Laboratory, Department of Electronics, Faculty of Technology, University of Frères Mentouri Constantine 1, 25000 Constantine, Algeria; Email: asmabenchiheb@yahoo.fr

Hamza Lidjici , LMAVER Laboratory for Renewable Energy Applications and Valorization, University of Laghouat, Algeria; Email: ha.lidjici@lagh-univ.dz

Fatima Bakhat , Process Engineering Laboratory (LGP), University of Laghouat, Algeria; Email: f.bekhat.gpr@lagh-univ.dz; Email: f.bekhat.gpr@lagh-univ.dz

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Wafa Bakhat, Asma Benchiheb, and Hamza Lidjici, Fatima Bakhat (2026), Computational Investigation of Interface Defects, Doping, and Emitter Thickness Effects in Front-and-Rear Illuminated Bifacial Heterojunction Solar Cells Using COMSOL Multiphysics. IJEER 14(3), 759-770. DOI: 10.37391/IJEER.140310.