Insights into Graphene Nanostructures, Fabrication Techniques, Mechanical, and Functional Behavior Characterization.

Graphene, a pioneering 2D carbon nanomaterial, has attracted significant attention owing to its exceptional structural, mechanical, thermal, and electrical performances. These intrinsic properties position it as a promising material platform for nanoelectromechanical systems, flexible electronics, and biomedical devices. Despite numerous existing reviews on graphene, a comprehensive assessment across graphene variants remains limited. Addressing this critical gap, this review provides an in-depth overview of the structural configurations, physical properties, and application domains of key graphene forms-including monolayer, bilayer, few-layer, and multilayer graphene, as well as functionalized derivatives. The review systematically discusses fabrication and synthesis strategies. Furthermore, it delves into state-of-the-art methodologies for mechanical characterization, highlighting experimental and computational techniques, including in situ scanning electron microscopy and transmission electron microscopy, atomic force microscopy, nanoindentation, tensile testing, Raman spectroscopy, and multiscale simulations based on molecular dynamics, density functional theory, coarse-grained modeling, and continuum mechanics. A comparative analysis of experimentally measured and computationally predicted mechanical properties is presented, elucidating existing discrepancies among methods. Collectively, this review aims to serve as a comprehensive reference for researchers at the intersection of nanomaterials, mechanics, and multifunctional material systems, offering a critical foundation for future research and the application of graphene nanostructures in next-generation technologies.