Helical SiNW design with a dual-peak response for broadband scattering in translucent solar cells

Abstract

Nanowires are widely used in optics, optoelectronics, photocatalysis, and photovoltaics because of their special optical properties. However, the narrow response spectrum of silicon nanowires (SiNWs) reduces the advantages of applications in photovoltaics. In this work, we designed a helical SiNW with an adjustable ultra-wide scattering spectrum for improving the light absorption of translucent solar cells by a simulation method combining optical and electrical dual physical fields. It is found that the helical SiNWs have three independent controllable characteristic scales to produce a dual-peak response in the scattering spectrum. Moreover, the position of the first peak can be accurately adjusted according to the comprehensive equation, and the radius and radial distance of the helix can adjust the position of the second peak. In addition, the distance between the two peaks can be flexibly adjusted to achieve a wide response spectrum, which realizes basically coverage of the optical gap absorption range of Si materials. Finally, the helical SiNWs are applied to a translucent SiNW array solar cell, and the light absorption increased to 40.86%, and the power conversion efficiency (PCE) increased to 5.85%, which is 40.03% and 50.39% higher than that of the cylindrical SiNW array solar cell, respectively.