Surface plasmon enhancement of polymer solar cells by penetrating Au/SiO2 core/shell nanoparticles into all organic layers

Abstract

We report the incorporation of Au@SiO2 core/shell nanoparticles (NPs) into bulk heterojunction polymer solar cell (BHJ-PSC) devices, leading to an obvious efficiency enhancement due to the localized surface plasmon resonance (LSPR) effect. The Au@SiO2 core/shell NPs comprise of large Au NPs with an approximate size of 70nm coated by a ∼50nm thick SiO2 shell. Such NPs were doped into the poly-(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer of P3HT:PCBM BHJ-PSCs, resulting in that the large NPs penetrate into all organic layers including the PEDOT:PSS buffer layer and P3HT:PCBM active layer, and are partially embedded in the Al cathode layer. The power conversion efficiency (PCE) of the P3HT:PCBM BHJ-PSC devices incorporated with Au@SiO2 NPs increased from 3.29% to 3.80%, and such a ∼16% efficiency enhancement can be primarily attributed to the light absorption enhancement, originating from the LSPR effect induced by Au NPs as confirmed by the UV–vis absorption spectrocopic study. Contrarily, the analogous P3HT:PCBM BHJ-PSC devices incorporated with bare Au NPs exhibited a lower efficiency enhancement, indicating that the coating of dielectric SiO2 shell is beneficial for the LSPR effect.