FDTD simulation studies on improvement of light absorption in organic solar cells by dielectric nanoparticles

In this paper, we present a systematic design and analysis of organic solar cell (OSC) by embedding dielectric nanoparticles layer at anode. Using numerical simulations, we show that there is improvement in the light absorption in the active layer of the device using nanoparticles. The nanoparticles will act as scattering medium for the incident light and hence trap the light inside the device. For the light scattered at different angles, the optical path length in the active medium is increased and this leads to more absorption of light in the active layer and thereby increase in the efficiency. The scattering efficiency and hence the absorption of solar radiation for generation of current depends on the particle size, interparticle separation and the refractive index contrast between the particles and the embedding medium. Mie theory has been used to calculate the scattering efficiency of nanoparticles. The effect on light absorption and current density of OSC due to nanoparticles has been carried out using finite difference time domain analysis. It is shown that the proposed OSC structure increases the light absorption in the active layer of the device by 40% and short circuit current density by 34%.