Abstract: Although dielectric-coated metallic nanoparticles were frequently applied in organic solar cells (OSCs) for improving the device performance by preventing the possible exciton quenching and charge recombination at the metal surface,there have been few theoretical researches addressing how the dielectric-coating of metal nanoparticles influences the optical performance of OSCs.The effect of coating silver nanaspheres were theoretically studied by a silica film on the absorption performance of OSCs.This results show that an integrated light absorption efficiency of 81.5; in the PSBTBT:PC71 BM active layer over the wavelength range from 350 nm to 850 nm at normal incidence,outperforming the structurally identical planar control cell by 9.54;.Detailed investigations reveal that the excitation of the dipole localized surface plasmon resonance,SPP and LSP and their mutual coupling are responsible for the observed broadband enhancement in light absorption.Through studying the influences of structure parameters,the results show that the thinner dielectric coating is more favorable for light absorption enhancement.In addition,refractive index impact on absorption enhancement of OSC is not obvious.

Key words: Although dielectric-coated metallic nanoparticles were frequently applied in organic solar cells (OSCs) for improving the device performance by preventing the possible exciton quenching and charge recombination at the metal surface,there have been few theoretical researches addressing how the dielectric-coating of metal nanoparticles influences the optical performance of OSCs.The effect of coating silver nanaspheres were theoretically studied by a silica film on the absorption performance of OSCs.This results show that an integrated light absorption efficiency of 81.5; in the PSBTBT:PC71 BM active layer over the wavelength range from 350 nm to 850 nm at normal incidence,outperforming the structurally identical planar control cell by 9.54;.Detailed investigations reveal that the excitation of the dipole localized surface plasmon resonance,SPP and LSP and their mutual coupling are responsible for the observed broadband enhancement in light absorption.Through studying the influences of structure parameters,the results show that the thinner dielectric coating is more favorable for light absorption enhancement.In addition,refractive index impact on absorption enhancement of OSC is not obvious.