Synergistic effect of graphene and ZnO nanorods in enhancing the performance of MEH-PPV based polymer light emitting diode

Abstract

The present work is an effort to enhance the performance of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) based light emitting diode by incorporating graphene and zinc oxide (ZnO) nanorods together in the device structure. The typical structure utilizes ZnO nanorods as single-mode waveguide for efficient light extraction and graphene nanoflakes as conductive nanofillers. The luminance characteristics depict that incorporation of ZnO nanorods leads to enhanced device emission while J-V curves show that with graphene doping there is a decrease in turn-on voltage of the device. This increase in luminance is ascribed to the light extraction capability of ZnO nanorods and the reduction in turn voltage is due to the development of graphene assisted electron transport pathways in the emissive layer. The analysis shows that at an optimized doping concentration of 0.005 wt% of graphene, the typical device has been found to be ∼ 60 times more efficient at 4 mA/cm2 than the basic MEH-PPV device owing to the cumulative action of these nanostructures.