Effect of Gold Nanoparticles on Optoelectronic Properties of Thermally Reduced Graphene Oxide

Abstract

Gold nanoparticles (AuNPs)-decorated reduced graphene oxide (rGO) is a compelling material from both aspects of processing and functionality. This paper presents an alternative method to prepare and alter the optoelectronic properties of the AuNPs-rGO hybrid film. Au was sputtered for a duration of 0–60 s on graphene oxide (GO) film before subjected to thermal reduction at 700∘C. The surface of rGO was decorated by spherical AuNPs with a mean particle size of around 10[Formula: see text]nm due to the solid-state dewetting process. The surface plasmon resonance (SPR) of AuNPs around 550[Formula: see text]nm was intense when the Au sputter duration exceeded 20[Formula: see text]s. Remarkably, the AuNPs layer retarded the de-oxygenation of GO during thermal annealing. The AuNPs-rGO hybrid film with long-duration Au sputtering exhibited low optical constants and thicker rGO film. The AuNPs also played the role in lowering the bandgap, increasing the lattice disorder and assisting the high-energy photon absorption in the thermally reduced rGO film. The sample of 30[Formula: see text]s and 40[Formula: see text]s Au sputtering was optimum to obtain the lowest sheet resistance of 59[Formula: see text]k[Formula: see text]/sq and 56[Formula: see text]k[Formula: see text]/sq, respectively. The sheet resistance was bargained between de-oxygenation retardation and doping by the AuNPs. Both samples of 30 s and 40 s Au sputtering were having a unique and satisfyingly strong absorption band around 260[Formula: see text]nm, 350[Formula: see text]nm and 555[Formula: see text]nm corresponding to [Formula: see text]* transition, [Formula: see text]* transition and SPR of AuNPs, respectively. Such properties are desirable in several applications such as a transparent electrode and optoelectronic sensor.