Strain‐Guided Oxidative Nanoperforation on Graphene

Abstract

Various fabrication methods have been proposed for generating tiny pores with controllable size in graphene sheets. [4,15] The top-down nanolithography (e.g., electron beam and ion beam bombardment) [16][17][18] and the bottom-up organic/on-surface syntheses [19] have been developed to create pores with desired size of 2−100 nm, however, both with complexity and time-expansiveness that hinder scalable applications. Chemically etching methods could treat large-area graphene but often introduce randomly distributed pores with poor edge quality. [8,10,20,21] Structurally uniform nanopores, especially with the pore size/neck width as narrow as several nanometers, are essential to achieve tunable bandgaps on a large sheet of graphene for electronic applications. [16,19] Previously reported precise fabrication methods, such as barrierguided chemical vapor deposition and thermally/catalytically activated noble metal nanoparticles apart from block copolymer lithography, [5,15,22,23] also experience high cost and low scalability that are detrimental to industrial applications. A facile and cost-efficient fabrication for selective nanoperforation with desired size/pattern on graphene still represents a challenge.We propose a simple and scalable strain-guided perforation method, where structural nanopores can be selectively fabricated on a strain-modulated 2D material (e.g., graphene, boron nitride) sheet by prepatterned nanoparticles (NPs) on substrate. As illustrated in Figure 1, NPs are firstly deposited on the substrate. Then, a monolayer of 2D material is transferred to cover and geometrically conform the NPs-decorated substrate, followed by oxidative etching. In essence, the highstrain magnitude near the bulges enhances the chemical Increased applications of nanoporous graphene in nanoelectronics and membrane separations require ordered and precise perforation of graphene, whose scalablility and time/cost effectiveness represent a significant challenge in existing nanoperforation methods, such as catalytical etching and lithography. A strain-guided perforation of graphene through oxidative etching is reported, where nanopores nucleate selectively at the bulges induced by the prepatterned nanoprotrusions underneath. Using reactive molecular dynamics and theoretical models, the perforation mechanisms are uncovered through the relationship between bulge-induced strain and enhanced etching reactivity. Parallel experiments of chemical vapor deposition (CVD) of graphene on SiO 2 NPs/SiO 2 substrates verify the feasibility of such strain-guided perforation and evolution of pore size by exposure of varied durations to oxygen plasma. This scalable method can be feasibly applied to a broad variety of 2D materials (e.g., graphene and h-boron nitride) and nanoprotrusions (e.g., SiO 2 and C 60 nanoparticles), allowing rational fabrication of 2D material-based devices. NanoperforationThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.

The Functional Chameleon of Materials Chemistry—Combining Carbon Structures into All‐Carbon Hybrid Nanomaterials with Intrinsic Porosity to Overcome the “Functionality‐Conductivity‐Dilemma” in Electrochemical Energy Storage and Electrocatalysis

“…[88] Another novel technique worth mentioning is a top-down technique, formation of holey graphene, as functionality is introduced in well-conductive graphene sheets. [89,90] In any case, a nanoscale homogenous hybrid material can only be formed if both materials do not form separated domains on the micrometer scale, which would result in characteristics that are rather close to those expected for the mechanical mixtures as usually obtained by top-down approaches such as ballmilling. Thus, from a chemical perspective, an attractive interaction between both parts is necessary.…”

“…[ 88 ] Another novel technique worth mentioning is a top‐down technique, formation of holey graphene, as functionality is introduced in well‐conductive graphene sheets. [ 89,90 ]…”

From nanohole to ultralong straight nanochannel fabrication in graphene oxide with swift heavy ions

“…The essential demand for these applications is that the created pores be well-shaped, uniform in size, and obtainable in a reproducible manner 1,16 . The majority of developed methods are based on etching of the reactive (e.g., defective 7 , highly oxidized 6,17,18 , strained 19,20 ) or catalyst-decorated [21][22][23] sites on GO sheets and, as such, typically offer only limited control over the porosity parameters and suffer from possible structure breakdown 12 . The etched GO sheets, once stacked into multilayer films, comprise a pore network consisting of randomly distributed in-plane holes and horizontal slit channels defined by the interlayer space 24,25 .…”