Solar Cells on the Base of Isotype Heterojunction Black Silicon - Crystalline Silicon

Simulations of the short-circuit current, open-circuit voltage, absorption coefficient, fill factor and power conversion efficiency of a p-type black silicon/p-type crystalline silicon isotype heterojunction were carried out. Such a heterojunction is part of a complex tandem 2T solar cell NiO – Perovskite – TiO₂ – black Si – crystalline Si. The expression used for the current-voltage characteristic of a heterojunction takes into account the electrical, optical and geometric parameters of both crystalline and black silicon. Analytical expressions were obtained for the absorption coefficients for both crystalline (for the wavelength range 700-1100 nm) and black silicon (for the wavelength range 300-700 nm). The best model data obtained for a short-circuit current density of ~31 mA/cm² and an open-circuit voltage of ~634 mV are obtained for the wavelength range 500-800 nm and are in good agreement with the results of previous numerical and experimental data for solar cells of similar composition and size. The calculations show the potential possibility of using black silicon in the design of tandem solar cells. The novelty of this work is the demonstration of the possibility of using thin layers of black silicon to convers solar energy. This material provides good absorption of photons with energy >1.4 eV. In combination with the crystalline silicon, black silicon can broaden the absorption spectrum of irradiation, thereby increasing the power conversion efficiency of the tandem solar cells.