Effective light trapping in c-Si thin-film solar cells with a dual-layer split grating.

Abstract

We propose a dual-layer split nanograting structure in crystalline silicon thin-film solar cells (TFSCs). The split nanograting is designed by introducing two partitioning factors and split times. By employing the finite-difference time-domain method, the light trapping performance and relevant parameters of TFSCs are analyzed and optimized. Numerical computation of optical and electrical simulation shows that the optimal dual-layer split nanograting structure has demonstrated great enhanced light absorption compared with the planar structure. Enhancement of the light trapping effect is associated with light coupling to waveguide modes. The short-circuit current density is reached at 21.66mA/cm2 with an improvement of 54.6% over the planar structure. All results provide a parting thought for the design of TFSC grating structures.