Directional Light Scattering and Absorption Enhancement by Nanoparticles and Nanoparticle Clusters with their Applications in Solar Energy Harvesting

Abstract

This thesis presents a computational study of the directional light scattering and absorption enhancement by nanoparticles and clusters of nanoparticles. The computational algorithm is based on the Mie electromagnetic-scattering theory with the addition-theorem recursive algorithm for electromagnetic scattering particles. Nanoparticles or nanoparticle aggregates are made into forward scattering of incident light by tuning the electric and corresponding magnetic modes of each particles in the cluster. Lossless broaden band forward scattering nanoparticle cluster is designed for the photovoltaic application. These nanoparticles and nanoparticle aggregates are incorporated into thin film solar cells and their performances in harvesting solar energy are evaluated and optimized by the use of Finite-Difference Time-Domain (FDTD) numerical method. Extensive simulations were carried out to identify the directional scattering nanoparticles and/or nanoparticle aggregates and to design solar cells incorporated with these nanoparticles. Analysis was conducted, with help of both analytical and numerical solutions, to explore fundamental physical mechanism governing light-particle and inter-particle interactions in nanoparticles and nanoparticle-thin film solar systems. Computed results for various nanoparticle-thin film solar configurations demonstrate that significant enhancement of light absorption in solar cell absorption can be obtained with the directional scattering nanoparticle and/or nanoparticle clusters over the solar cells enhanced by non-directional scattering particles reported in literature.