Improving thin film solar cells performance via designing moth-eye-like nanostructure arrays

Abstract

Herein, bioinspired moth-eye-like nanostructures are presented as a possible solution for overcoming the limitation of weak absorption by thin film silicon solar cells. The interaction mechanism between the incident wave and such an artificial nanostructure is revealed by using the finite-difference time-domain method. Optical simulations show that the addition of biomimetic nanostructured surface reduces the refractive indices difference from external media environment to cell devices, thereby leads more incident light propagated into the active material. The optical design yield power conversion efficiencies of 14.6% and 17.5% for 2 and 5 μm thick absorbing layers, respectively. Further analysis depended on the equivalent medium theory demonstrates that a smooth, non– abrupt effective refractive index curve plays a key role for the light harvesting. The proposed method of addressing the weak absorption problem by thin film solar cells shows great promise.