Structural, optical and electrical properties of ribbon-like graphene oxide thin films

Abstract

Graphene oxide is a unique material whereas it can be semiconductor or an insulating material depending on its degree of oxidation and dimensions. In this paper we report ribbon-like structure of spin-coated graphene oxide thin film with unusual optical and electrical characteristic. The films were prepared by spin coating technique with a variety of spin speed from 1000 rpm to 4000 rpm and annealed at 50 °C in a vacuum oven. Atomic force microscopy (AFM) revealed a ribbon-like structure with 32-200 nm. Further analysis by conductive AFM (C-AFM) showed an unexpected electrical conducting side at the edges of the ribbon-like structure. Optical characterization also unveiled the visible photoluminescence spectra at the peak wavelength of 397 nm while optical absorption estimates the band gap of 2.64 eV for each sample. The films were also tested as electron buffer layer in polymer light emitting devices and showed an enhancement of light intensity from 179 cd m −2 to 444 cd m −2 for 25 nm thin films. This shows the films have a high potential in optoelectronic applications.