WS₂ 2D nanosheets in 3D nanoflowers

Abstract

In this work it has been established that 3D nanoflowers of WS2 synthesized by chemical vapour deposition are composed of few layer WS2 along the edges of the petals. An experimental study to understand the evolution of these nanostructures shows the nucleation and growth along with 10 the compositional changes they undergo.The structural analogy of transition metal dichalcogenides 1 to graphite's layered structure, held together by van In this work, a fast, catalyst free and easily scalable chemical vapour deposition (CVD) technique for the controlled synthesis of well-defined tungsten disulphide (WS2) nanomaterials on (100) silicon-based substrates using tungsten(VI)chloride (WCl6-40 2 mmol at 99.9% purity) and sulphur (20 mmol at 80% purity) as precursors is presented in Fig S1. The predominant morphology (>90%) obtained by this process is WS2 nanoflower confirmed using electron microscopy as shown in Fig.1a and the chemistry verified using XRD and Raman in Fig S2. The morphology of the 45 WS2 nanostructures synthesised by the CVD technique can be tailored through the variation of just two key parameters: time 22 , as yet, a detailed analysis of their structure has not been undertaken. This 60 study looks to comprehend the structure of the nanoflower by disassembling it with the help of sonication. The nanoflowers disassembled into triangular petals (flakes) on sonication with one corner always broken, which suggests that these triangles are connected at only one of the edges to form the assembly of 3D 65 nanoflowers. We observed 10-100's of these triangular petals combining together to form spherical nanoflower structures as suggested by Li et al. 22 and evident from the SEM micrograph in Fig 1a. The nanoflowers are made up of molecular sheets stacked 70 together with a lattice spacing of 3.1 Å and lattice fringes of 0.62 nm, inferred for WS2. In Fig 2a, a cluster of the petals which constitute the nanoflowers is visualised from the edge view (beam perpendicular to c-axis), to reveal 6-8 molecular layers of WS2. These WS2 were stacked on top of each other to form the 75 petals. The distribution of the number of molecular layers to form the petal is not very uniform and varies from few layer (2-4) to increased number of layers up to 12/14. With the beam parallel to the c axis, the hexagonal packing can be clearly observed at the edges where the number of layers have reduced considerably to 80 1 µm

Flower-like supramolecular self-assembly of phosphonic acid appended naphthalene diimide and melamine

“…Flower-shaped morphologies of crystallized mineral salts (calcium sulphate) are seen in nature 46 and often even in inorganic material systems 19 20 21 22 23 , very rare in organic 24 25 26 27 28 29 30 31 material but never happen in water due to their solubility properties. To the best of our knowledge, the flower-shaped morphology forming in aqueous medium described herein is the first example of such assembly being observed in a supramolecular system containing two organic components (NDI appended phosphonic acid (Phos-NDI) and melamine (MM)).…”

“…During the past few years flower-shaped inorganic 19 20 21 22 23 /organic 24 25 26 27 28 29 30 31 assemblies gained attention of researchers because of their potential applicability in the field of catalysis, superhydrophobic (non-wetting) materials, explosives detection materials, magnetic materials, biomedical materials and optoelectronic materials 19 20 21 22 23 24 25 26 27 28 29 30 31 . Recently, the first organic flower-shaped morphology via self-organization of functionalized C 60 derivative was reported by Nakanishi and co-workers 32 .…”

The application of nanostructured transition metal sulfides as anodes for lithium ion batteries

“…It is still challenging to fabricate stable mono-and few-layer with large scale. Besides, various morphologies, such as nanosheets [133] , nanoflowers [134] , nanotubes [135,136] have been synthesized. Benefiting from the large surface area and shorter Li + diffusion pathway of nanostructure, building nanostructure exhibited a promising strategy to enhance the Li + intercalation and deintercalation.…”

Flower-like superstructures of AIE-active tetraphenylethylene through solvophobic controlled self-assembly

“…The massive morphological changes of supramolecular assemblies have been widely investigated, however, flower-like assemblies of small organic molecules are rare. During the past decade, flower-shaped inorganic 13 14 15 16 17 /organic 18 19 20 21 22 23 24 assemblies gained the attention of researchers due to their potential applications in the various fields such as catalysis, superhydrophobics, explosives detection, magnetic materials, biomedical and optoelectronic materials. In this regards, Nakanishi and co-workers reported the formation of organic flower-shaped morphology via self-organization of functionalised C 60 derivative 25 .…”