Graphene
The theory of graphene was first explored by Wallace in 1947 as a starting point for understanding the electronic properties of 3D graphite. The emergent massless Dirac equation was first pointed out by Semenoff, DiVincenzo and Mele. The earliest TEM images of few-layer graphite were published by Ruess and Vogt in 1948. An early, detailed study on few-layer graphite dates to 1962 when Boehm and colleagues reported producing monolayer flakes of reduced graphene oxide. Efforts to make thin films of graphite by mechanical exfoliation started in 1990, but nothing thinner than 50 to 100 layers was produced before 2004. Initial attempts to make atomically thin graphitic films employed exfoliation techniques similar to the drawing method. Multilayer samples down to 10 nm in thickness were obtained.
Graphene spray gun
Upon departing the spray gun, the graphene flake’s tendency to aggregate is reduced due to its quick evaporation and dispersion. Much to the researchers’ surprise, this spray method produces flakes that contain substantially less defects that would commonly occur. Common graphene defects including holes and lumps in the layer, and the Stone-Wales defect were absent upon surface impact. The large amount of kinetic energy delivered by the supersonic nozzle creates the healing of these defects, as the graphene flakes stretches upon impact. The carbon atoms within the graphene rearrange to create seamlessly perfect hexagonal lattice structures. The result of these perfect hexagon structures is the creation of a smooth, even layer of graphene. This is a large contrast to the applications of graphene onto large-scale substrates prior to the creation of the graphene spray gun. The graphene layers would commonly contain defecting clumps and spaces, which troubled scientists ever since the discovery of graphene. The graphene spray gun is also regarded as inexpensive when compared to the other methods of large-scale graphene applications. One main factor for its inexpensiveness is that the graphene layers require no post-processing treatment, which was common in the other methods. The other factor is that the spray gun is remarkably simple in both its production and utilization.