Ultra-thin crystalline silicon solar cell with a stepped pyramid nanostructure for efficient absorption

Abstract

Incorporating micro-nano structures onto the surface of crystalline silicon (c-Si) solar cells to optimize their light absorption capability and improve photoelectric conversion efficiency is a feasible approach. Here, we propose an ultra-thin c-Si solar cell with a stepped pyramid nanostructure for efficient absorption, which consists of the Ag reflective layer, the c-Si absorption layer, and the c-Si stepped pyramid structure. The calculated outcomes demonstrate that the ultra-thin c-Si solar cell’s average absorption at the wavelength of 350–1100 nm is 90.9%, while the average absorption for AM1.5G solar radiation is 92.1%. By comparing the absorption of solar cells with a different number of steps, it’s proved that the proposed solar cell achieves optimal absorption. Investigation into the electric field distribution reveals that the high absorption of the solar cell is generated through the dipole resonance, local electric field enhancement, and combined effects of multiple light reflections and scattering. The calculation of the electrical output characteristics shows that the proposed solar cell achieves a photoelectric conversion efficiency of 21.2%. This study will provide a meaningful exploration into the design and optimization of solar cells that can use solar energy efficiently.