Broadband absorption enhancement achieved by optical layer mediated plasmonic solar cell.

We propose a novel thin solar cell design, integrating plasmonic component with optical layer, for conspicuous performance improvement in organic (P3HT: PCBM) thin film solar cell. Despite the relatively simple structure, the designed solar cell can get strikingly high spectral performance with the short circuit current density (J(sc)) enhancement up to 67%; and a nicely large J(sc) enhancement over 50% can be easily obtained spanning rather a broad geometric parametric range. The mechanisms responsible for this significant and broadband absorption enhancement as well as the effects of intercalating a plasmonic nanoparticles (NPs) array and an optical layer are theoretically and systematically investigated by finite-difference time-domain calculations (FDTD). The origin of the dramatically increased absorption is believed to be the synergistic effect between 1) the enhanced electric field and forward scattering upon excitation of localized surface plasmon resonance (LSPR) of the NPs, and 2) the favorable redistributions of light field in the device due to the beneficial interference effect mediated by the optical layer. Such a design concept is quite versatile and can be easily extended to other thin film solar cell systems.