Broadband angle-independent antireflection coatings on nanostructured light trapping solar cells

作     者：Abraham Vázquez-Guardado Javaneh Boroumand Daniel Franklin Debashis Chanda 

作者机构：CREOL College of Optics and Photonics University of Central Florida Orlando Florida 32816 USA NanoScience Technology Center University of Central Florida Orlando Florida 32826 USA Department of Physics University of Central Florida Orlando Florida 32816 USA 

出 版 物：《Physical Review Materials》 (Physic. Rev. Mat.)

年 卷 期：2018年第2卷第3期

页      面：035201-035201页

核心收录：

基　　金：National Science Foundation, NSF National Science Foundation, NSF, (ENG/CMMI-1450806) 

主　　题：Light propagation, transmission & absorption Nanostructures Finite-difference time-domain method Lithography Optical spectroscopy 

摘      要：Backscattering from nanostructured surfaces greatly diminishes the efficacy of light trapping solar cells. While the analytical design of broadband, angle-independent antireflection coatings on nanostructured surfaces proved inefficient, numerical optimization proves a viable alternative. Here, we numerically design and experimentally verify the performance of single and bilayer antireflection coatings on a 2D hexagonal diffractive light trapping pattern on crystalline silicon substrates. Three well-known antireflection coatings, aluminum oxide, silicon nitride, and silicon oxide, which also double as high-quality surface passivation materials, are studied in the 400–1000 nm band. By varying thickness and conformity, the optimal parameters that minimize the broadband total reflectance (specular and scattering) from the nanostructured surface are obtained. The design results in a single-layer antireflection coating with normal-angle wavelength-integrated reflectance below 4% and a bilayer antireflection coating demonstrating reflection down to 1.5%. We show experimentally an angle-averaged reflectance of ∼5.2% up to 60° incident angle from the optimized bilayer antireflection-coated nanostructured surface, paving the path toward practical implementation of the light trapping solar cells.