Laser flash synthesis of graphene and its inorganic analogues: An innovative breakthrough with immense promise

Laser-based green synthetic approaches for 2D atomic sheets of graphene, graphene nanoribbons and inorganic analogues of graphene are relatively new techniques. There are several significant laser-based approaches for graphene synthesis such as (a) laser exfoliation, (b) intercalation and exfoliation in liquid nitrogen, (c) pulsed laser deposition, (d) laser induced ultrafast chemical vapour deposition, (e) laser induced catalyst-free growth of graphene from solid carbon sources, (f) epitaxial graphene growth on a Si rich surface of SiC by laser sublimation of surface silicon atoms, (g) reduction of graphene oxide and (h) unzipping of carbon nanotubes. Apart from the deoxygenation of graphene, lasers have also been employed for the dehydrogenation and dehalogenation of graphene surfaces. Such laser induced bond dissociation paves the way for achieving the desired band gap in graphene by adequately controlling the extent of such surface bonds. Such photochemical transformations can be exploited for patterning and nanolithography of graphene and related materials. Laser exfoliation has successfully been extended to synthesize inorganic analogues of graphene such as 2D atomic sheets of hexagonal BN and metal dichalcogenides such as MoS2, MoSe2, WS2, WSe2 etc. It is noteworthy that the emerging novel laser-based approaches have tremendously simplified the synthesis of 2D atomic sheets and are capable of yielding impurity-free device quality 2D materials in a scalable manner and consequently inspiring various commercial applications of such materials. An overview of the progress made into laser based approaches is presented.