Quickie Method For High-Quality Graphene

Materials chemists have found a quick, high-yield approach for producing single sheets of defect-free graphene by adding powdered graphite to an ionic liquid and subjecting the suspension to microwave irradiation (Nat. Chem. 2015, DOI: 10.1038/nchem.2315). Graphene’s potential use in advanced microelectronics applications has led researchers to devise numerous ways of obtaining the ultrathin carbon material. For example, high-quality graphene sheets can be produced by exfoliating graphite flakes by hand and by growing graphene via vapor-deposition techniques. But those methods have low yields and can be costly. In contrast, liquid-phase exfoliation of graphite with oxidizers and acids followed by a reduction step can inexpensively produce large quantities of an oxidized form of graphene—so-called reduced graphene oxide. But that material is generally pocked with defects, and it contains a variety of functional groups that render it quite different from pristine graphene. Takuzo Aida of the University of Tokyo and coworkers have now demonstrated that microwaving graphite with an oligomeric ionic liquid (IL2PF₆ or IL4PF₆, shown) converts almost all of the starting material to a nearly defect-free form of graphene in just 30 minutes.