Optical Impedance Matching Using Coupled Plasmonic Nanoparticle Arrays

Abstract

Silver nanoparticle arrays placed on top of a high-refractive index substrate enhance the coupling of light into the substrate over a broad spectral range. We perform a systematic numerical and experimental study of the light incoupling by arrays of Ag nanoparticle arrays in order to achieve the best impedance matching between light propagating in air and in the substrate. We identify the parameters that determine the incoupling efficiency, including the effect of Fano resonances in the scattering, interparticle coupling, as well as resonance shifts due to variations in the near-field coupling to the substrate and spacer layer. The optimal configuration studied is a square array of 200 nm wide, 125 nm high spheroidal Ag particles, at a pitch of 450 nm on a 50 nm thick Si(3)N(4) spacer layer on a Si substrate. When integrated over the AM1.5 solar spectral range from 300 to 1100 nm, this particle array shows 50% enhanced incoupling compared to a bare Si wafer, 8% higher than a standard interference antireflection coating. Experimental data show that the enhancement occurs mostly in the spectral range near the Si band gap. This study opens new perspectives for antireflection coating applications in optical devices and for light management in Si solar cells.

Nanoplasmonics: a frontier of photovoltaic solar cells

“…There are many commercially available FDTD software vendors [67] , which are easy-to-use and can simulate 2D and 3D cases. The published FDTD research outcomes include the investigation of nanostructure shape, material, dielectric environment, array pitch and location in the cell structure with regard to the scattering into the substrate [18,31,37,44,45,59,60,68] .…”

A Mini Review: Antireflective Coatings Processing Techniques, Applications and Future Perspective

“…There are various factors which limit usage of multilayer AR coatings, such as in the multilayer stack adhesion strength at interfaces, mismatch thermal properties of different oxide coatings, complex, intricate e-ISSN: 2321-6212 p-ISSN: 2347-2278 fabrication process, mechanical stability decrement due to multilayer stacks, and expensive cost restricts their usage. Recently advancement in metamaterial AR coatings unlocks a new direction to fabricate ultra-thin coatings [53,54] . …”

Light Trapping in Plasmonic Solar Cells

“…The disadvantage is that, since the particles are on top, attention must be paid to the density of objects to avoid shadowing. The presence of particles on top also modifies the use of AR coatings, and so any added benefits from nanoparticles must be weighed against the benefits due to conventional antireflection methods [55,56].…”