Simultaneous Visualization of Graphene Grain Boundaries and Wrinkles with Structural Information by Gold Deposition

Abstract

Although line defects such as grain boundaries (GBs) and wrinkles are unavoidable in graphene, difficulties in identification preclude studying their impact on electronic and mechanical properties. As previous methods focus on a single type of line defect, simultaneous measurements of both GBs and wrinkles with detailed structural information have not been reported. Here, we introduce effective visualization of both line defects by controlled gold deposition. Upon depositing gold on graphene, single lines and double lines of gold nanoparticles (NPs) are formed along GBs and wrinkles, respectively. Moreover, it is possible to analyze whether a GB is stitched or overlapped, whether a wrinkle is standing or folded, and the width of the standing collapsed wrinkle. Theoretical calculations show that the characteristic morphology of gold NPs is due to distinct binding energies of line defects, which are correlated to disrupting diffusion of NPs. Our approach could be further exploited to investigate the defect structures of other two-dimensional materials.

Evaporation induced wrinkling of graphene oxide at the nanoparticle interface

“…By searching the literature, we found that many other nanoparticles produced wrinkles on GO as well. 13,[30][31][32][33][34] Our own experiment also indicated that silica nanoparticles can produce very obvious wrinkling ( Figure S2A). On the other hand, if GO is dried by itself, no extensive wrinkling was observed ( Figure 2F).…”

A facile method for the selective decoration of graphene defects based on a galvanic displacement reaction

“…24 Cu fatigue cracks have a very specific type of shallow lines with a spacing of approximately 200 nm. In addition, the topographical features of the underlying Cu foil, such as fatigue cracks, can be transferred to synthesized graphene by CVD 23,25 such that the shallow lines on the Cu foil can cause local fractures on the graphene. In our results, the line shape and spacing of the Pd parallel lines are nearly identical to the shallow lines of the Cu fatigue cracks.…”

“…Defect sites present on the SLG layer, including GBs and intrinsic topological defects, act as electronically favorable sites for Pd deposition because of their chemical instability. 25,26 Therefore, graphene imperfections effectively function as nucleation sites, as observed when Pd NPs were formed on both graphene GBs and graphene regions over Cu fatigue cracks. Defect sites that act as nucleation sites for Pd can be generated during the galvanic displacement reaction.…”

“…23 First-principles calculations in other studies have demonstrated that graphene wrinkles have higher binding energy than GBs. 25 Because graphene wrinkles are produced as a consequence of the different thermal expansion coefficients of graphene and Cu during the CVD growth process, 4,9,24,29 wrinkle shapes, which are indistinguishable from other various structures, vary depending on the growth conditions. Therefore, we prepared pristine graphene, which has numerous wrinkles, by controlling the CVD growth conditions to investigate Pd deposition onto graphene wrinkles during the galvanic displacement reaction.…”

First‐Principle‐Based Phonon Transport Properties of Nanoscale Graphene Grain Boundaries

“…Indeed, to fully exploit the extraordinary promises of this first truly 2D material, the production of large size and good quality graphene layers has to be mastered. One of the most promising routes is the growth of graphene by chemical vapor deposition on various metal surfaces 4. However, similar to many other macroscopic materials, graphene exists in polycrystalline structures, with numerous 1D topological defects called grain boundaries (GBs) 5, 6, 7, 8, 9.…”