Stability of few layer graphene films doped with gold (III) chloride

In this paper we study the stability of few layer graphene (5-7 layers) doped with gold nanoparticles through spin coating of a gold (III) chloride solution. Specifically sheet resistance, optical transmittance and surface morphology were monitored over a period of four weeks. Through scanning electron microscopy we observed that the gold nanoparticles of 29.1 +/- 1.3 nm diameters, which were formed on surfaces freshly doped with a 20 mM solution, agglomerate and fuse over the period of four weeks into larger particles of 50-110 nm diameters. At the end of four weeks of aging, regardless in air or vacuum, the optical transmittance at 550nm for the doped samples resumed a value close to that of undoped samples. During these four weeks, the sheet resistances of the samples doped with 20mM gold chloride also increased from 130 ohm/sq to 300 ohm/sq, but stayed comparable to indium tin oxide. In summary, despite the instability of doped FLG surfaces obtained using gold (III) chloride solutions, this study warrants the use of doped FLG films for building the next generation photovoltaics. (C) 2016 Elsevier B.V. All rights reserved.