The preliminary result showed an interesting behavior of lower current, higher and broader EL spectra with the insertion of graphene oxide as hole buffer layer. The GO layer is made from a curled up sheet of graphene stacking together forming spider web like nanostructured. Compared to normal insulator GO, the Scanning Conductive Microscopy showed a semiconducting behavior for this spider web like nanostructured. The enhancement and interesting phenomenon of the OLED are assumed by the ease of charge into the OLED via the percolation network form by the GO layer. We believe that the lower current and higher EL is due to the ease of charge conduction. However, the cause of broader EL is supposed to the coupling of the exciton energy with the vibrational structure of the polymer in the excited state that may lead to a variation in the effective band gap. Our observation (Fig. 1 and Fig. 2) showed the EL intensity as high as 304 candela at 0.79 watts for devices with additional GO buffer compared to 179 candela at 1.37 watt for control devices. Details of the experiment and updated result will be further discussed in the full paper.
© 2015 Optical Society of AmericaPDF Article