Enhanced light trapping in thin film solar cells by Ag/Al2O3 core- shell nanoparticles

In this paper, the localized surface plasmon properties of Ag NPs and Ag/Al2O3 coreshell NPs with core radii ranging from 20-120 nm were analyzed by Mie scattering theory. Using numerical simulations, we show that an increasing shell thickness for coreshell NPs results in a red-shifted plasmon resonance peak compared to Ag core NPs. An averaged scattering efficiency under AM1.5 illumination is used to characterize the scattering abilities of different NPs. For Ag/Al2O3 core-shell structures, the averaged scattering efficiency increases and subsequently decreases with increasing shell thickness due to the competing influences of plasmon hybridization and phase delay. For larger radii NPs, such as R > 100 nm, the scattering abilities of core-shell structures are superior to those of spherical Ag NPs.