Graphene-based papers and films

Graphene-based 2D materials have been reported in the open literature [1-3]. In this chapter, two parts are included, i.e., (i) thin fi lms that are deposited on substrates and (ii) free-standing forms, which are known as papers, sheets, membranes and so on. There are slight overlappings between these two groups of materials in specifi c aspects. For example, vacuum membrane fi ltration can be used to fabricate both thin fi lms and membranes. If the items are deposited on a given substrate, they are called thin fi lms. Otherwise, if they are free-standing, they will be named as papers or membranes. For thin fi lms, the thickness is usually at sub-micron level, whereas the membranes or papers could be as thin as micrometers or as thick as tens or even hundreds of micrometers. Although attempts have been made to standardize the names of these materials, it is diffi cult to do so in most cases, because of the high diversity of the sources that the references are coming from. Most likely, the nomenclature in this book follows the names of specifi c references, due to the consideration to match the context with the corresponding fi gures as much as possible.