Computational Study of Plasmon Interaction in Organic Media: a Comparison Between Analytical and Numerical Model for Dimer

In the present work, an investigation of wavelength-dependent absorption spectrum of spherical nanoparticles with different arrangements in organic medium using discrete dipole approximation (DDA) has been performed. Specifically, we study the impact of different arrangements such as monomer, dimer (compositionally symmetric and asymmetric), 1D array of spherical nanoparticle on surface plasmon resonance (SPR) peak position, and its spectral broadening in distinct regimes of the electromagnetic spectrum. Three different organic materials such as P3HT:PCBM blend (Poly(3-hexyl thiophene))-(phenyl-C61-buryricacid methyl ester), P3HT(poly (3-hexyl thiophene)), and PEOPT ((4'-(1, 4, 7-trioaoctyl) phenyl) theophany) have been chosen in the present work to study the absorption and scattering spectrum of MNP. Further, near-field pattern of homo-dimer nanogeometry is also shown in the present study. We also observed that on increasing the interacting number of particles in 1D array, the corresponding FWHM (full width at half maxima) value increases as well, which covers the large spectral region of the electromagnetic spectrum. The comparison between dipole model and numerical model has been performed to analyze the extinction behavior of smaller size (d << ) metal nano dimer which shows a good agreement in 400-600nm wavelength range.