A few layers of graphene sheets prepared by an electrochemical method enhance the performance of organic photovoltaic device

Abstract

A composite has been prepared by incorporating few layers of graphene sheets (FLGS) synthesized by an electrochemical method in poly (3-hexylthiophene-2, 5-diyl) (P3HT): [6], [6]-phenyl-C61-butyric acid methyl ester (PCBM). The composite has been used as active layer in the photovoltaic device (ITO/FLGS:P3HT:PCBM/Al) and the device characteristics were investigated. The as prepared FLGS has been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), Ultraviolet–visible spectroscopy (UV–Vis), and Raman spectroscopy. The performance of the composite based device has been studied under illumination and the results have been compared with the reference device (ITO/P3HT:PCBM/Al). Short circuit current density (Jsc) of 6.24 mA.cm−2, open circuit voltage (Voc) of 0.54 V, Fill factor (FF) of 44.22% and solar power conversion efficiency (PCE) of 1.49% have been obtained for reference photovoltaic device. After introducing FLGS in the active layer with P3HT:PCBM blend, improvement of Jsc of 8.2 mA.cm−2, Voc of 0.57 V, FF of 42.15% and solar power conversion efficiency of 1.97% have been observed. The performance improvement in FLGS incorporated device compared to the reference device is attributed to the advantage of electron accepting feature and high electron transport capability of FLGS.