Quantifying the Exfoliation Ease Level of 2D Materials via Mechanical Anisotropy

Abstract

The isolation of 2D materials from mother bulks into nanoscale is of vital importance for fulfilling their applications in many technological fields. Among known methods, mechanical exfoliation is one of the most widely utilized ways due to its simplicity. For a given 2D material, both its interlayer and its intralayer bonding strengths need to be taken into account for understanding the exfoliation process as the former dominates the ease level for cleaving adjacent molecular layers while the latter regulates the ability to resist cracking. In this regard, strong intralayer but weak interlayer bonding interactions respectively lead to large and thin nanosheets and, hence, facile exfoliation (and vice versa). As the bonding forces can be directly reflected through elastic properties of materials, here we propose to use the ratio between the in-plane and out-of-plane elastic modulus (E) as a universal index, A In/Out (= E In-plane /E Out-of-plane ), to quantify the ease level of a 2D material's mechanical exfoliation. Such ratios, which can be facilely obtained from routine computational and mechanical experiments, could provide useful information for estimating suitable exfoliation methods of 2D materials.

Electronic structures and elastic properties of a family of metal-free perovskites

“…Up to now, the electronic and elastic properties of inorganic and organic-inorganic perovskite materials have been comprehensively researched. [17][18][19][20][21][22] However, very limited information is known about the electronic structures and elastic properties of metal-free perovskite materials, 23,24 which will certainly delay their future industrialization. In this work, the electronic and elastic properties of a family of metal-free perovskites: [(C 4 N 2 H 12 )(NH 4 X 3 )ÁH 2 O] (X = Br, Cl, I), called PIP-Cl, PIP-Br and PIP-I, respectively, have been systematically investigated, using the first principle calculations.…”

Elastic and hydrostatic behaviour of a zinc dietary supplement, zinc glycinate hydrate

“…This A E value is about an order of magnitude lower than graphite, and about 50% of those values from those of h-BN, MoS 2 , WS 2 , black P and a layered hybrid perovskite [(benzylammonium) 2 PbBr 4 ] 30. Accordingly, the low A E of ZnG gives rise to a lower ease level of exfoliation,31 as observed from AFM and TEM experiments. Furthermore, the difference in E (100) and E (010) can be explained by the underlying structural arrangements within the pseudo-2D layer.…”

A Mini Review of the Preparation and Photocatalytic Properties of Two-Dimensional Materials

“…In addition, Aparna et al used the auxiliary effect of methanol solution of 1-pyridine formic acid, and this auxiliary effect can be applied to other 2D materials besides graphene (Aparna et al, 2013). Ji et al select eight representative 2D materials (graphite, h-BN, MoS 2 , WS 2 , black phosphorus, metalorganic framework Mn(C 6 H 8 O 4 ) (H 2 O) and two kinds of layered coordination polymer) with diverse inter-and intra-layer bonding interactions for the study, proposing to use the ratio between the inplane and out-of-plane elastic modulus (E) as a universal index, A In/Out (= E In−plane /E Out−of−plane ), to quantify the ease level of a 2D material's mechanical exfoliation (Ji et al, 2018). (Cai et al, 2018).…”