Controlling the optical scattering of plasmonic nanoparticles using a thin dielectric layer

Abstract

The effect of a thin dielectric film on the plasmonic behaviour of metal nanoparticles (MNPs) above a high refractive index substrate is explored. Using finite-difference time domain simulations, the optical properties of Ag nanoparticles are investigated as a function of film thickness, refractive index, and particle position within the film. We demonstrate that the addition of a film around a MNP at the air interface of a high-index substrate, where n air < n f ilm < n substrate , will always increase the fraction of light coupled to the substrate (F subs ). It is found that placement within a layer that does not conform to n air < n f ilm < n substrate can lead to reduced enhancements in F subs . The principal application for this work is for light-trapping in thin-film solar cells. We show that the inclusion of a thin film can increase the fraction of radiation coupled into the substrate by up to 30% for solar wavelengths. Additional potential benefits of the film structure, such as greater tunability of scattering resonances, an increase in path length of light in the substrate, and some control over the emission pattern are demonstrated. MNPs in a film are found to produce a more finely structured emission pattern than particles at a simple interface, showing potential for this research to be applied to optical nanoantennae. V

Plasmonic effects and the morphology changes on the active material P3HT:PCBM used in polymer solar cells using Raman spectroscopy

“…b) redshift as compared with that of the extinction spectra of the bare Ag NWs (Fig. S4 (Supporting Information)), which are because of the refractive index increase in the environment of the Ag NWs . It is noted that the plasmonic sample with 60‐nm diameter Ag NWs shows the maximum relative extinction within the range of 300–500 nm as compared with other plasmonic samples.…”

Plasmonic metal nanocubes for broadband light absorption enhancement in thin-film a-Si solar cells

“…Generally, this reveals the minimum absorption that can be expected from an array of optimally placed particles. 26 Here, along with Fig. 7(d), we can see part of the reason for the poor performance of Al MNPs at longer wavelengths.…”

Optical Properties of Metal Subwavelength Structures for Realistic Geometries in a Dielectric Matrix Using DDA: an Error Analysis

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