An anode buffer layer with size-controlled Ag nanoparticles for polymer solar cells with improved efficiencies

Abstract

We systematically studied the plasmonic effects in polymer solar cells (PSCs) by using an anode buffer layer, in which size-controlled silver nanoparticles (NPs) (diameter: 4, 28, 55, and 75 nm, respectively) are incorporated into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The optical properties of the buffer layer as well as the device performance of the resulting devices were investigated. We found that Ag NPs with an average diameter of 55 nm showed good behavior on enhancing light absorption due to the plasmonic scattering effect. Subsequently, the power conversion efficiency (PCE) of the PSC with Ag NPs (55 nm) improves to as high as 9.45% in comparison with a value of 7.90% for the control device without Ag NPs. In addition, the open circuit voltage, photocurrent and fill factor are simultaneously increased. The external quantum efficiency and light absorption are significantly enhanced in the range of ∼400–550 nm as compared to the control device. These results demonstrate that embedding Ag NPs into PSCs offers an effective strategy to improve the performance of optoelectronic devices.