Thorough numerical simulations of silicon heterojunction solar cells focusing on the sun-side-doped layer

To improve the photovoltaic conversion efficiency (PCE) of silicon heterojunction (SHJ) solar cells, this study focuses on optimizing the physical parameters of the sun-side-doped layer and proposes strategies to address the challenges posed by Fermi level pinning in wide bandgap designs. Using AFORS-HET simulations, we systematically investigate the effects of bandgap width, doping concentration, and defect state distribution on the energy band structure, interface electric field, and carrier transport dynamics. The results reveal that maintaining the Fermi level within 0.3 eV of the conduction band is essential for optimal device performance. A wider bandgap (> 1.8 eV) enhances the utilization of short-wavelength light and significantly suppresses interface recombination, leading to an increase in short-circuit current density (J_sc) by 0.8 mA/cm². This benefit comes with a delicate balance between minimizing defect state density and improving doping efficiency. This study provides theoretical insights into the optimization of doped layer physical parameters and proposes practical solutions, including nano-crystallization and low-doping interface strategies, to improve the performance of SHJ solar cells and support industrial applications.