Numerical simulation of metal subwavelength nanogeometries in organic media using DDA technique: a coupled broadband resonant near electric field perspective

Abstract

A simulation model for estimation of the optical properties of spherical and spheroid nano plasmonic geometry coupled with organic media has been studied using discrete dipole approximation (DDA) technique. Silver (Ag) and aluminium (Al) metal nano particles (NPs) are used as a plasmonic element surrounded by organic photovoltaic environment [poly (3-hexyl thiophene)] P3HT-(phenyl-C61-buryricacid methyl ester) PCBM blend. The analysis done in the current article depicts considerable influence of shape, aspect ratio and size on the plasmon resonance that facilitates improvement in the performance of nano plasmonic organic system in the useful spectral domain (250–750 nm). Discretisation of dipoles have been done in the DDA and compared with Mie theory to maintain the accuracy of DDA technique. It has been established that the oblate shape Ag and Al NPs with size of 80 nm (both) with aspect ratio 0.35 and 0.20 are the optimized parameter to enhance the optical properties in an organic surrounding. The optical properties are studied in terms of wavelength dependent extinction spectrum and resonant electric field distribution. Broadband electromagnetic field coupling under the plasmonic effect has led to considerable improvement in the photon absorption inside the organic environment that has been supported by the enhanced J–V curve for different nano geometries. Results of the present article can be used as a guiding principle for the plasmonic light trapping devices to improve their optical properties and electrical properties.