Raman scattering of true 1D van der Waals Nb₂Se₉ nanowires

Abstract

In the present study, the experimental Raman spectrum of niobium‐selenide nanowires (Nb2Se9) is reported for the first time followed by an analysis of the Raman spectrum using the density functional theory (DFT). According to the group‐theoretical analysis, 33 Ag modes were identified as Raman active modes. In the experimental spectrum, 19 well‐resolved Raman modes were observed: 13 modes in the low‐wavenumber range (50–200 cm−1) and six modes in the high‐wavenumber range (220–340 cm−1). The DFT calculations were performed using the local‐density approximation (LDA) functional and generalized gradient approximation (GGA) functional of Perdew–Burke–Ernzerhof (PBE) with van der Waals corrections (PBE‐D3). PBE‐D3 showed better compatibility with the experimental data for the high‐wavenumber range. Our results provide an essential reference for the Raman scattering of newly synthesized Nb2Se9 nanowires and nanodevices in the future.

One-dimensional van der Waals transition metal chalcogenide as an anode material for advanced lithium-ion batteries

“…The lattice parameters are a = 8.180 Å, b = 8.323 Å, and c = 13.083 Å, which agree well with the reported structural details for Nb 2 Se 9 . 21,33 The SEM and TEM images (Fig. 1b, c, and S1 †) conrmed that the rod structure of 1D vdW Nb 2 Se 9 has tens of micro-sized lengths and a diameter distribution of 100-500 nm.…”

The effect of the metal and selenium precursors on the properties of NbSe2and Nb2Se9nanostructures and their application in dye-sensitized solar cells

“… 26 On the other hand, the vibrational modes of Nb 2 Se 9 were at 239.62 cm −1 due to two Nb atoms vibrating along the (101) plane and the two Se pairs with a stretching motion. 27 The second vibrational motion at 284.18 cm −1 was due to two pairs of stretching Nb atoms crossed and all the Se atoms vibrating in the outward direction at the same time. 28 …”

Raman spectroscopy of phonon states in NbTe4 and TaTe4 quasi‐one‐dimensional van der Waals crystals

“…In recent years, there has been a growing interest in onedimensional (1D) van der Waals materials, which reveal interesting phenomena, such as nontrivial band topology, superconductivity, magnetism, and charge-density-wave (CDW) formation. [1][2][3][4][5] The CDW quantum condensate phase, often observed in quasi-1D materials, is a periodic modulation of the electron charge density that is accompanied by a periodic distortion of the underlying crystal lattice. [6][7][8] Transition metal tri-chalcogenides (MX 3 , M: transition metal, X: chalcogen), transition metal trihalides, and transition metal tetra-chalcogenides (MX 4 ) are examples of compounds that encompass a variety of 1D structures.…”

“…1,2 Generally, 1D materials can be classified into "true-1D" and "quasi-1D" systems, depending on the relative strength of the atomic bonds along different crystallographic directions compared with the chain direction. 1,2 In "true-1D" materials, atoms form strong covalent bonds along the atomic chains, accompanied by weak van der Waals bonds along all other directions. 1,9,10,21 Quasi-1D crystals also feature strong covalent bonds along the atomic chains but exhibit weaker covalent or ionic bonds along other directions.…”