Metal Nanoparticle Induced Enhancement of Light Absorption in Thin-film PV Cells

Abstract

The aim of this thesis is to investigate the utilization of plasmonic metal nanostructures for efficiency enhancement of thin-film solar cells. This efficiency enhancement strategy exploits the strong near-field enhancement and highly efficient light scattering that originates from localized surface plasmon resonances (LSPRs) excited in metal nanostructures and leads to an increased absorption in the solar cell active layer. In the first part of this thesis, the near-field enhancement is explained with rigorous theoretical details and how the electromagnetic characteristics alters significantly if a nanoparticle interacts with an incoming field. We have simulated in COMSOL the incoming electric and magnetic field pattern for a single dielectric particle. We have also shown the far-field radiation pattern and scattering characteristics. We have also demonstrated the enhanced resonant electric field (Hot Spot) and wavelength for peak electric field between 2 nanoparticles in close proximity. Later on, we have constructed models where we chose different metal nanoparticles (Al, Cu, Ag, Au) covered by thin-film absorber layer (GaAs, CdTe). We have measured the enhanced magnitude of absorption and scattering in presence of each of these nanoparticles which boosts the efficiency of an otherwise lacking thin-film absorber without the implementation of nanoparticles. Also we have demonstrated how varying the size of the nanoparticles impacted on the absorption enhancement. We have also delved into the recently emerging organic solar cell technology, very particularly, the Perovskite solar cell. Introducing nanoparticles into the Perovskite absorber layer results in higher absorption and scattering. We have measured the absorption enhancement in presence of different noble metal NPs (Al, Cu, Ag, Au). Also we have demonstrated the effect of the radius of the each of the metal NPs into absorption enhancement. Due to this absorption enhancement, the plasmonic nanostructured cell exhibits an enhanced power conversion efficiency compared to an optimized, high performance organic solar cell