Embedded plasmonic nanoprisms in polymer solar cells: Band-edge resonance for photocurrent enhancement

Abstract

Introduction of metallic nanoparticles that can generate the surface plasmon resonance (SPR) has been considered as a prominent option for enhancing the performance of polymer solar cells (PSCs), as the radiative scattering and field confinement by the SPR can extend the effective photon traveling length and manipulate the spatial absorption profile. Despite many successful efforts to favorably exploit metallic nanoparticles, further studies of their effects on the PSC performance have been demanded to achieve the full benefit from them. Here, we systematically investigate the optical and photovoltaic performances of PSCs with disorderly distributed silver nanoprisms embedded in the photoactive material. Due to the superior properties of the plasmonic scattering of this class of nanoparticles, a significant improvement of photon absorption is gained from the devices with silver nanoprisms, particularly in the wavelength range of substandard absorption property including the band-edge wavelengths. While such absorption improvement can be obviously reinforced as an increase in the particle density, its level becomes saturated and decayed eventually because of the concurrently promoted photon loss by plasmonic absorption. At the optimal configurations of silver nanoprisms for the productive light trapping effect, the incorporated PSC devices present a photocurrent of ∼17.76 mA/cm2 and a power conversion efficiency of ∼9.68%, where their net increase ratios are ∼10% and ∼13% compared to the reference PSC devices, respectively. Details of numerical modeling and experiments for both metal nanoprisms and PSC devices offer an optimum route to tailoring metallic nanoparticles for high-performance PSC systems.