Thananchai Dasri

Theoretical calculation of plasmonic enhancement of silver nanosphere, nanocube, and nanorod embedded in organic solar cells

ABSTRACT Due to organic solar cells having metallic nanoparticle such as silver (Ag) nanoparticles incorporated into active layer exhibit significant improvement in device efficiency compared with the reference device. Therefore, the basic of optical effected, scattering and absorption efficiencies, of silver nanoparticle in different morphologies (nanosphere, nanocube and nanorod) were investigated by using Discrete Dipole Approximation. The observed silver NPs spectra showed strong interaction with electromagnetic field due to the excitation of localized surface plasmons resonance (LSPR). By varying nanosphere diameter from 10 to 50 nm, the spectra showed that the resonance peaks appeared within the interval wavelength of 400 to 600 nm. Also, the resonance peaks were shifted to longer wavelength and broadening. Silver nanocube with the side length in the range 44.20–25.21 nm, the spectra were gradually shifted to longer wavelength as the dimension increase. Moreover, the two resonance peaks were found at the wavelength around 360–380 nm and 430–470 nm. The spectra of 5 silver nanorods, which nanorod axis was aligned perpendicular with the propagation direction of light and parallel to the polarization of electric field, exhibited two resonance peaks in each dimension. The main peak appeared within the wavelength range from 600 to 900 nm. The shifting peaks were also observed for varying the dimensions of nanorod.

Simulation of Absorption Spectra of Metal Nanoparticles Embedded in Organic Media

Metal nanoparticles, silver and gold, of different sizes and shapes are actively being researched in a variety of different fields such as solar cells. The unique plasmonic properties of these particles, especially in the visible and NIR-region ranging from 400-1200 nm, are the basis for most of these applications. The absorption spectra are calculated using the discrete dipole approximation (DDA) in the wavelength region of 300 to 1200 nm. The modeled samples for calculating are planar array nanoparticles, basically two particles and more than two particles. The influences of the nanoparticle size, interparticle distance and polarization direction of excited light on the absorption spectra are investigated. Moreover, the optical absorption can be tuned by adjusting sizes and shape of nanoparticles to obtain the enhanced absorption. The influence of the surrounding medium is also presented.