Enhancing the efficiency of polymer solar cells by embedding Au@Ag NPs Durian shape in buffer layer

Abstract

Organic semiconducting polymers are useful in several photonic applications due to their tunable optical and electronic properties and ease of fabrication. However, due to the short exciton diffusion length and low carrier mobility of polymer solar cell (PSC) materials, their power conversion efficiency (PCE) is comparably lower than their inorganic counterparts. Therefore, this study introduces plasmonic effects into these organic polymer-based solar cells by incorporating Au@Ag nanoparticles (NPs) to improve their performance. The plasmonic NPs (Au@Ag durian-shaped NPs), which can be placed in the hole transport layer (HTL) of the PSC, scatter light into the active layer thereby increasing the optical path length of the incident light, leading to higher absorption and short circuit current density of the PSCs. The shape of nanoparticles is an important factor since it directly affects surface plasmonic resonance (SPR) and the incident light’s scattering. The proposed Au@Ag NPs (with many sharp spikes) confirmed the effect of small radii of the spike ends of the durian-shaped NPs on the performance PSCs. The results reveal that the embedded Au@Ag NPs improve the electrical properties of both the active layer and HTL in PSCs. In more detail, Au@Ag NPs create plasmon-electrical effects which shorten transport path length of the low-mobility holes and lengthen that of high-mobility electrons for better-balanced carrier collection. Meanwhile, the resistance of HTL is reduced by Au@Ag NPs. Therefore Jsc and PCE of up to 17 mA/cm2 and 3.73%, respectively, implies a 44.4% improvement in short-circuit photocurrent density and 49% enhancement of the power conversion efficiency compared to the reference cell.