Ionic liquid-functionalized carbon nanoparticles-modified cathode for efficiency enhancement in polymer solar cells

Abstract

The power conversion efficiency (PCE) of regioregular poly(3- hexylthiophene) (P3HT) and {6,6}-phenyl C61 -butyric acid methylester (PCBM)-based polymer solar cells was increased using an ionic liquid-functionalized carbon nanoparticles (ILCNs) thin film-modified cathode. The PCE of P3HT:PCBM based-polymer solar cells with a conventional aluminum (Al)-only cathode was increased by 20%-30% when the identical devices were made with an ILCNs-modified Al cathode, but its PCE was 10% lower than that of devices with LiF/Al cathode, measured under AM1.5G illumination of 100 mW/cm. The ILCN interlayer approach, however, offers practical advantages to LiF in terms of its solution-processability, which is compatible with low cost, large area, and flexible solar cell fabrication. © 2009 American Institute of Physics.