Metal Oxide Nanosheets as 2D Building Blocks for the Design of Novel Materials

Abstract

Research into 2‐dimensional materials has soared during the last couple of years. Next to van der Waals type 2D materials such as graphene and h‐BN, less well‐known oxidic 2D equivalents also exist. Most 2D oxide nanosheets are derived from layered metal oxide phases, although few 2D oxide phases can be also made by bottom‐up solution syntheses. Owing to the strong electrostatic interactions within layered metal oxide crystals, a chemical process is usually needed to delaminate them into their 2D constituents. This Review article provides an overview of the synthesis of oxide nanosheets, and methods to assemble them into nanocomposites, mono‐ or multilayer films. In particular, the use of Langmuir–Blodgett methods to form monolayer films over large surface areas, and the emerging use of ink jet printing to form patterned functional films is emphasized. The utilization of nanosheets in various areas of technology, for example, electronics, energy storage and tribology, is illustrated, with special focus on their use as seed layers for epitaxial growth of thin films, and as electrochemically active electrodes for supercapacitors and Li ion batteries.

Epitaxial lift-off of freestanding (011) and (111) SrRuO3 thin films using a water sacrificial layer

“…However, the introduction of buffer layers on Si suffers from complexities due to the reduction reaction and interdiffusion between oxides and Si at the interface while retaining the epitaxial relationship 8 – 10 . Alternatively, oxide nanosheets have been considered as crystalline templates to bridge TMOs and Si 11 , 12 . Although various TMO thin films have been directed in single out-of-plane orientation using oxide nanosheets 12 – 14 , true epitaxy has not been achieved over the large scale on Si substrates yet.…”

Tribology of 2D Nanomaterials: A Review

“…Since their discovery, they have undoubtedly attracted great academic and industrial interests due to their magnificent array of electronic, optical, physical, and chemical properties which are absent in their bulk counterparts [17]. These unique features are a result of the effect of their spatial confinement in one dimension [18]. Besides, since nanosheets are atomically thin and possess strong in-plane bonds, they are liable to exhibit a remarkable combination of thermal, high mechanical strength and flexibility which are desirable properties for use in various devices [19], which can also result to unusual frictional features [20,21].…”

“…The high degree of flexibility associated with 2D materials whenever they are in contact with nearby objects plays a vital role in deciding the real contact area and the frictional pinning potential [22,23]. Besides, the dispersion of 2D materials in aqueous solution are suitable precursors for the design of 2D based films [24], and since all atoms of 2D materials are surface atoms, it provides a proper handle to tune the properties and functionalities of the materials by mode of surface functionalization and modification [25,26].…”

Fast and efficient shear-force assisted production of covalently functionalized oxide nanosheets

“…[1] Such systems can find applications in various domains : nanofillers in polymer-based materials, [2] energy and environmental applications, [3][4][5] or magnetic materials in spintronics [6,7] to quote just a few. [8][9][10] Nanosheets can also be used in nanoarchitectonics to design multifunctional "artificial solids" from their obtain decorated nanosheets. Nevertheless, the development of microwave assisted reactions has recently considerably sped up the functionalization processes, [39][40][41][42][43] thus enabling to overcome this difficulty.…”