Effective reduction of graphene oxide thin films by a fluorinating agent: Diethylaminosulfur trifluoride

This paper reports the use of a fluorinating agent, diethylaminosulfur trifluoride (DAST), to effectively reduce graphene oxide (GO) thin films at a relatively low temperature (50 °C). X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and sheet resistance measurement were used to investigate the reduction process. The C/O atomic ratio and sheet resistance of the GO films reduced by DAST were 9.24 and 398 Ω/□ respectively, which are comparable to the reduced GO films of similar thickness (6.5 μm) produced by hydrazine vapor. GO film reduction by DAST is advantageous in preserving the film intactness, owing to the mild reaction conditions involved. A small amount of fluorine (3-4 at.%) was incorporated into rGO by DAST reduction which was confirmed by XPS and FTIR, which might influence the electrical properties of rGO or render it suitable for further functionalization. Further, our findings suggest that special attention should be paid to the steric hindrance of the hydroxyl groups in GO while adapting organic chemistry methods for GO reduction and functionalization, which could alter reaction outcome significantly and could also be exploited for steric protection.