Effects of Magnetic Field on the Film Morphology and Photoelectric Properties of the Active Layer P3HT:PCBM

A series of poly (3-hexylthiophene)(P3HT)/[6, 6]-phenyl-C₆₁ butyric acid methyl ester (PCBM) bulk heterojunction polymer solar cells were fabricated via a simple method, i.e.applying an external magnetic field on the active layer in its annealing process, which is based on the magnetic field effect on the alignment of the active layer's molecules.The experimental results demonstrate that the maximum photoelectric conversion efficiency (PCE) of 2.562% is achieved when the magnetic intensity is 0.9MA/m.The short-circuit current density is raised from 7.414mA/cm² to 8.332mA/cm², and the fill factor from 0.512% to 0.543%, but the open-circuit voltage almost remains the same.As characterized by the photoluminescence spectrum and atomic force microscope (AFM), the magnetic field had obvious effects on the molecular alignment and the crystallinity of the active layer and the surface morphology of film.