University of Tehran Journal of Solar Energy Research 2588-3097 11 2 2026 05 12 The effect of SiC polytype on the solar cell characteristics: a simulation study 2977 2991 106868 10.22059/jser.2026.410248.1710 EN Rand Kareem Husein College of Science, Al-Karkh University of Science, Baghdad, Iraq Burak Yahya Kadem College of Science, Al-Karkh University of Science, Baghdad, Iraq Journal Article 2026 01 29 Solar cells based on P3HT, SiC, and ZnS were examined via SCAPS-1D to estimate the impact of different silicon carbide (SiC) polytypes as an interlayer, including 3C-SiC, 4H-SiC, and 6H-SiC, on device performance. Different analyses were conducted to explain charge transport and interfacial behavior, including current-voltage (J-V), external quantum efficiency (EQE), Mott-Schottky, and recombination rate. Among the studied solar cells, using 3C-SiC interlayer exhibited the highest performance and a clear reduction in interfacial recombination, achieving a short-circuit current density (J_SC) of 15.18 mA/cm², a fill factor (FF) of 81.6%, and a power conversion efficiency (PCE) of 19.2%. Conversely, 6H-SiC has resulted in moderate improvements, whereas 4H-SiC led to a decline in performance. Further optimization of the 3C-SiC interlayer thickness, particularly in the 70-100 nm range, proved critical in balancing band bending, interfacial passivation, and carrier extraction, factors that collectively contributed to maximizing both FF and PCE. Further examinations were carried out to study the effects of trap density, effective density of states, series and shunt resistances, and illumination conditions to evaluate their significance on the solar cell performance. These findings demonstrate that appropriate SiC polytype with careful interface engineering, plays an essential role in enhancing the efficiency of solar cells. https://jser.ut.ac.ir/article_106868_8f2d69545adff2a9d6d7084b45f5da48.pdf