دانلود رایگان مقاله سوسپانسیون گرافون چند لایه متمرکز و پایدار در حلال آلی

Abstract

Highly stable graphene suspensions in pure organic solvents, including volatile solvents such as ethanol, tetrahydrofurane, chloroform, acetone or toluene have been prepared by re-dispersion of a graphenepowder. Such re-dispersable solid is produced by precipitation or solvent elimination from graphene suspensions obtained by sonication of graphite in several organic solvent–water mixtures. Re-dispersion is feasible in a wide range of pure organic solvents, obtaining high quality few-layers graphene flakes stable in suspension for months. As a proof-of-concept, on-glass spray deposition of some of these suspensions, e.g. ethanol or tetrahydrofuran, results on electrically conductive transparent coatings. These results suggest industrial potential use of the scalable technology here developed to fabricate low-cost devices with many different potential applications.

4. Conclusions

The simple preparation procedure here reported enables the possibility to obtain graphene suspensions in a variety of pure organic solvents (such as ethanol, tetrahydrofurane, chloroform, acetone or toluene). These few-layers graphene suspensions are formed from a graphene-powder isolated as a result of LPE of graphite in a mixture of water–THF. It is worth mentioning that the suspensions show high graphene concentrations in a variety of pure solvents where direct graphite exfoliation is not feasible, and they are very stable remaining almost unaltered upon standing at room temperature for 2 months. The morphological features of the suspensions consisting of few-layer high quality graphene flakes with lateral dimensions up to 500 nm and a nanometer thickness (ca. 6 nm) suggestthatthey are suitable to be sprayed on a variety of substrates. We showed a proof-of-concept application ofthese suspensions consisting of on-glass spray deposition of these graphene suspensions to produce electrodes with a good electrical conductivity vs transparency ratio. The results obtained suggest potential applications for production of transparent conductive electrodes. The results reported herein present several advantages with respect the state-of-the-art of graphene suspensions obtention by means of LPE. The present technology provides and efficient, scaleup and inexpensive method for the fabrication of graphene coatings and the possibility to produce graphene devices.