A comparative study on few-layer graphene production by exfoliation of different starting materials in a low boiling point solvent

Abstract

Three different graphite-based powders (expandable graphite and two different nano-graphite powders) were investigated as starting materials for an effective liquid phase exfoliation process in isopropyl alcohol (IPA). The prepared dispersions were analyzed and compared in terms of their graphene concentration, stability, number of graphene layers and quality, as well as the electrical conductivity of the prepared graphene-based materials. Good quality graphene dispersions (I D /I G < 0.3) with a relatively high concentration ($1.1 mg/ml) were prepared in IPA within 90 min sonication time by utilizing a high specific surface area ($175 m 2 /g) nano-graphite powder derived from natural graphite. Transmission electron microscope analyses of this sample revealed mostly folded and scrolled few layer graphene (FLG) sheets (<5 layers) entangled each other. The electrical conductivity of the thin film prepared from this dispersion was $15 and 86 S/m, before and after annealing, respectively. FLG prepared from expanded graphite, obtained by thermal treatment of expandable graphite, exhibited both much higher quality (I D / I G < 0.09) and electrical conductivity ($2104 and 19,200 S/m before and after annealing, respectively) when dispersed in IPA for 90 min. However, the graphene-based material concentration of the prepared dispersion was relatively low ($0.06 mg/ml).

The effect of starting material types on the structure of graphene oxide and graphene

“…However, the C/O atomic ratios for GR1 and GR2 were close to those of the BR and ST techniques and lower than that of the HU method. Moreover, Çelik et al [3] presented As a result, high-quality GR in the current study was synthesized directly from NG, without any pretreatments, according to the chemical and thermal reduction studies of GR in the literature. HCTEM images of the NG, GNp, GO1, and GO2 are shown in Figure 9.…”

Towards scale‐up of graphene production via nonoxidizing liquid exfoliation methods

“…An intercalation process could be used to produce expanded flake graphite. This pretreated precursor could then be used in an exfoliation process to produce graphene with beneficial properties, such as high electrical conductivity . This pretreatment, however, should be thoroughly controlled and assessed to mitigate any unwanted changes in important graphene properties.…”

Properties of Nanographite Formed by Plasma Deposition and Subsequent Heat Treatment

“…Нанографит может являться прекурсором для получения графена [1]. Графен и его производные представляют интерес не только из-за высокой электро-и теплопроводности, механической прочности [2,3], но также обладают сенсорными свойствами для создания оптоэлектронных, биологических, газовых, механических сенсоров [2,4] и имеют широкие возможности для практических приложений.…”