Nanotubes from Transition Metal Dichalcogenides: Recent Progress in the Synthesis, Characterization and Electrooptical Properties.

Inorganic layered compounds (2D-materials), particularly transition metal dichalcogenide (TMDC), are the focus of intensive research in recent years. Shortly after the discovery of carbon nanotubes (CNTs) in 1991, it was hypothesized that nanostructures of 2D-materials can also fold and seam forming, thereby nanotubes (NTs). Indeed, nanotubes (and fullerene-like nanoparticles) of WS2 and subsequently from MoS2 were reported shortly after CNT. However, TMDC nanotubes received much less attention than CNT until recently, likely because they cannot be easily produced as single wall nanotubes with well-defined chiral angles. Nonetheless, NTs from inorganic layered compounds have become a fertile field of research in recent years. Much progress has been achieved in the high-temperature synthesis of TMDC nanotubes of different kinds, as well as their characterization and the study of their properties and potential applications. Their multiwall structure is found to be a blessing rather than a curse, leading to intriguing observations. This concise minireview is dedicated to the recent progress in the research of TMDC nanotubes. After reviewing the progress in their synthesis and structural characterization, their contributions to the research fields of energy conversion and storage, polymer nanocomposites, andunique optoelectronic devices are being reviewed. These studies suggest numerous potential applications for TMDC nanotubes in various technologies, which are briefly discussed.

Nanotubes from Lanthanide-Based Misfit-Layered Compounds: Understanding the Growth, Thermodynamic, and Kinetic Stability Limits.

Gaining insights into the kinetics and the thermodynamic limits of nanostructures in high-temperature reactions is crucial for controlling their unique morphology, phase, and structure. Nanotubes from lanthanide-based misfit-layered compounds (MLCs) have been known for more than a decade and were successfully produced mostly via a chemical vapor transport protocol. The MLC nanotubes show diverse structural arrangements and lattice disorders, which could have a salient impact on their properties. Though their structure and charge transfer properties are reasonably well understood, a lack of information on their thermodynamic and kinetic stability limits their scalable synthesis and their applicability in modern technologies. In this study, the growth, thermodynamic stability, and decomposition kinetics of lanthanide-based misfit nanotubes of two model compounds, i.e., (LaS)1.14TaS2 and (SmS)1.19TaS2 are elucidated in detail. The nanotubes were carefully analyzed via atomic resolution electron microscopy imaging and synchrotron-based X-ray and electron diffraction techniques, and the information on their morphology, phase, and structures was deduced. The key insights gained would help to establish the parameters to explore their physio-chemical properties further. Furthermore, this study sheds light on the complex issue of the high-temperature stability of nanotubes and nanostructures in general.

Mechanism of WS2 Nanotube Formation Revealed by in Situ/ex Situ Imaging.

Multiwall WS2 nanotubes have been synthesized from W18O49 nanowhiskers in substantial amounts for more than a decade. The established growth model is based on the "surface-inward" mechanism, whereby the high-temperature reaction with H2S starts on the nanowhisker surface, and the oxide-to-sulfide conversion progresses inward until hollow-core multiwall WS2 nanotubes are obtained. In the present work, an upgraded in situ SEM µReactor with H2 and H2S sources has been conceived to study the growth mechanism in detail. A hitherto undescribed growth mechanism, named "receding oxide core", which complements the "surface-inward" model, is observed and kinetically evaluated. Initially, the nanowhisker is passivated by several WS2 layers via the surface-inward reaction. At this point, the diffusion of H2S through the already existing outer layers becomes exceedingly sluggish, and the surface-inward reaction is slowed down appreciably. Subsequently, the tungsten suboxide core is anisotropically volatilized within the core close to its tips. The oxide vapors within the core lead to its partial out-diffusion, partially forming a cavity that expands with reaction time. Additionally, the oxide vapors react with the internalized H2S gas, forming fresh WS2 layers in the cavity of the nascent nanotube. The rate of the receding oxide core mode increases with temperatures above 900 °C. The growth of nanotubes in the atmospheric pressure flow reactor is carried out as well, showing that the proposed growth model (receding oxide core) is also relevant under regular reaction parameters. The current study comprehensively explains the WS2 nanotube growth mechanism, combining the known model with contemporary insight.

Polyetherimide (PEI) nanocomposite with WS2 nanotubes.

Nanocomposite materials, integrating nanoscale additives into a polymer matrix, hold immense promise for their exceptional property amalgamation. This study delves into the fabrication and characterization of polyetherimide (PEI) nanocomposite strings fortified with multiwall WS2 nanotubes. The manufacturing process capitalizes on the preferential alignment of WS2 nanotubes along the string axis, corroborated by scanning electron microscopy (SEM). Mechanical measurements unveil a remarkable acceleration of strain hardening in the nanocomposite strings, chiefly attributed to the WS2 nanotubes. Structural analyses via X-ray diffraction (XRD) and wide-angle X-ray scattering (WAXS) reveal intriguing structural alterations during tensile deformation. Notably a semi-crystalline framework ∼100 nm in diameter surrounding the WS2 nanotubes emerges, which is stabilized by the π-π interactions between the PEI chains. The amorphous majority phase (97% by volume) undergoes also major structural changes upon strain becoming more compact and closing-up of the distance beweeetn the PEI chains. Dynamic mechanical analysis (DMA) demonstrates improved thermal stability of the evolved semi-crystalline π-π oriented PEI molecules, characterized by delayed thermal "structural melting", underscoring the pivotal role of the WS2 nanotubes in reinforcing the nanocomposite. The insight gained in this study of WS2 nanotube-reinforced PEI nanocomposite strings, could offer diverse applications for such tailor-made polymeric materials.

W18O49 Nanowhiskers Decorating SiO2 Nanofibers: Lessons from In Situ SEM/TEM Growth to Large Scale Synthesis and Fundamental Structural Understanding.

Tungsten suboxide W18O49 nanowhiskers are a material of great interest due to their potential high-end applications in electronics, near-infrared light shielding, catalysis, and gas sensing. The present study introduces three main approaches for the fundamental understanding of W18O49 nanowhisker growth and structure. First, W18O49 nanowhiskers were grown from γ-WO3/a-SiO2 nanofibers in situ in a scanning electron microscope (SEM) utilizing a specially designed microreactor (µReactor). It was found that irradiation by the electron beam slows the growth kinetics of the W18O49 nanowhisker, markedly. Following this, an in situ TEM study led to some new fundamental understanding of the growth mode of the crystal shear planes in the W18O49 nanowhisker and the formation of a domain (bundle) structure. High-resolution scanning transmission electron microscopy analysis of a cross-sectioned W18O49 nanowhisker revealed the well-documented pentagonal Magnéli columns and hexagonal channel characteristics for this phase. Furthermore, a highly crystalline and oriented domain structure and previously unreported mixed structural arrangement of tungsten oxide polyhedrons were analyzed. The tungsten oxide phases found in the cross section of the W18O49 nanowhisker were analyzed by nanodiffraction and electron energy loss spectroscopy (EELS), which were discussed and compared in light of theoretical calculations based on the density functional theory method. Finally, the knowledge gained from the in situ SEM and TEM experiments was valorized in developing a multigram synthesis of W18O49/a-SiO2 urchin-like nanofibers in a flow reactor.

Encapsulation of Uranium Oxide in Multiwall WS2 Nanotubes.

Uranium is a high-value energy element, yet also poses an appreciable environmental burden. The demand for a straightforward, low energy, and environmentally friendly method for encapsulating uranium species can be beneficial for long-term storage of spent uranium fuel and a host of other applications. Leveraging on the low melting point (60 °C) of uranyl nitrate hexahydrate and nanocapillary effect, a uranium compound is entrapped in the hollow core of WS2 nanotubes. Followingly, the product is reduced at elevated temperatures in a hydrogen atmosphere. Nanocrystalline UO2 nanoparticles anchor within the WS2 nanotube lumen are obtained through this procedure. Such methodology can find utilization in the processing of spent nuclear fuel or other highly active radionuclides as well as a fuel for deep space missions. Moreover, the low melting temperatures of different heavy metal-nitrate hydrates, pave the way for their encapsulation within the hollow core of the WS2 nanotubes, as demonstrated herein.

0D van der Waals interfacial ferroelectricity.

The dimensional limit of ferroelectricity has been long explored. The critical contravention is that the downscaling of ferroelectricity leads to a loss of polarization. This work demonstrates a zero-dimensional ferroelectricity by the atomic sliding at the restrained van der Waals interface of crossed tungsten disufilde nanotubes. The developed zero-dimensional ferroelectric diode in this work presents not only non-volatile resistive memory, but also the programmable photovoltaic effect at the visible band. Benefiting from the intrinsic dimensional limitation, the zero-dimensional ferroelectric diode allows electrical operation at an ultra-low current. By breaking through the critical size of depolarization, this work demonstrates the ultimately downscaled interfacial ferroelectricity of zero-dimensional, and contributes to a branch of devices that integrates zero-dimensional ferroelectric memory, nano electro-mechanical system, and programmable photovoltaics in one.

Submillimeter-Long WS2 Nanotubes: The Pathway to Inorganic Buckypaper.

WS2 nanotubes present many new technologies under development, including reinforced biocompatible polymers, membranes, photovoltaic-based memories, ferroelectric devices, etc. These technologies depend on the aspect ratio (length/diameter) of the nanotubes, which was limited to 100 or so. A new synthetic technique is presented, resulting in WS2 nanotubes a few hundred micrometers long and diameters below 50 nm (aspect ratios of 2000-5000) in high yields. Preliminary investigation into the mechanistic aspects of the two-step synthesis reveals that W5O14 nanowhisker intermediates are formed in the first step of the reaction instead of the ubiquitous W18O49 nanowhiskers used in the previous syntheses. The electrical and photoluminescence properties of the long nanotubes were studied. WS2 nanotube-based paper-like material was prepared via a wet-laying process, which could not be realized with the 10 µm long WS2 nanotubes. Ultrafiltration of gold nanoparticles using the nanotube-paper membrane was demonstrated.

The Mechanical Properties Relationship of Radiation-Cured Nanocomposites Based on Acrylates and Cationic Polymerized Epoxies and the Composition of Silane-Modified Tungsten Disulfide Nanoparticles.

The effect of semiconducting tungsten disulfide (WS2) nanoparticles (NPs), functionalized by either methacryloxy, glycidyl, vinyl, or amino silanes, has been studied in photocuring of acrylate and epoxy resins (the latter photocured according to a cationic mechanism). The curing time, degree of curing (DC), thermal effects, and mechanical properties of the radiation-cured resins were investigated. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analyses confirmed that a silane coating was formed (1-4 nm) on the NPs' surface having a thickness of 1-4 nm. Fourier transition infrared (FTIR) was used to determine the DC of the nanocomposite resin. The curing time of the epoxy resin, at 345-385 nm wavelength, was 10 to 20 s, while for acrylate, the curing time was 7.5 min, reaching 92% DC in epoxy and 84% in acrylate. The glass transition temperature (Tg) of the photocured acrylates in the presence of WS2 NPs increased. In contrast to the acrylate, the epoxy displayed no significant variations of the Tg. It was found that the silane surface treatments enhanced the DC. Significant increases in impact resistance and enhancement in shear adhesion strength were observed when the NPs were treated with vinyl silane. A previous study has shown that the addition of WS2 NPs at a concentration of 0.5 wt.% is the optimal loading for improving the resin's mechanical properties. This study supports these earlier findings not only for the unmodified NPs but also for those functionalized with silane moieties. This study opens new vistas for the photocuring of resins and polymers in general when incorporating WS2 NPs.

Silane functionalization of WS2 nanotubes for interaction with poly(lactic acid).

Functionalisation of nanofillers is required for the promotion of strong interfacial interactions with polymers and is essential as a route for the preparation of (nano)composites with superior mechanical properties. Tungsten disulphide nanotubes (WS2 NTs) were functionalized using (3-aminopropyl) triethoxysilane (APTES) for preparation of composites with poly(lactic acid) (PLA). The WS2 NTs : APTES ratios used were 1 : 1, 1 : 2 and 1 : 4 WS2 NTs : APTES. The APTES formed siloxane networks bound to the NTs via surface oxygen and carbon moieties adsorbed on the WS2 NTs surface, detected by X-ray photoelectron spectroscopy (XPS) studies and chemical mapping using energy dispersive X-ray spectroscopy in the scanning transmission electron microscope (STEM-EDS). The successful silane modification of the WS2 NTs was clearly evident with both significant peak shifting by as much as 60 cm-1 for Si-O-Si vibrations (FTIR) and peak broadening of the A1g band in the Raman spectra of the WS2 NTs. The evolution of new bands was also observed and are associated with Si-CH2-CH2 and, symmetric and assymetric -NH3+ deformation modes (FTIR). Further evidence for functionalization was obtained from zeta potential measurements as there was a change in surface charge from negative for pure WS2 NTs to positive for APTES modified WS2 NTs. Additionally, the thermal stability of APTES was shifted to much higher temperatures as it was bound to the WS2 NTs. The APTES modified WS2 NTs were organophilic and readily dispersed in PLA, while presence of the pendant amine and hydroxyl groups resulted in strong interfacial interactions with the polymer matrix. The inclusion of as little as 0.5 wt% WS2 NTs modified with 2.0 wt% APTES resulted in an increase of 600% in both the elongation at break (a measure of ductility) and the tensile toughness relative to neat PLA, without impacting the stiffness or strength of the polymer.

Improved Electrochemical Performance of NTs-WS2@C Nanocomposites for Lithium-Ion and Sodium-Ion Batteries.

Even though WS2 nanotubes (NTs-WS2) have great potential as anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) thanks to their unusual layered structure, their conductivity and cycling stability are far from satisfactory. To tackle these issues, carbon-coated WS2 (NTs-WS2@C) nanocomposites were prepared through a facile synthesis method that involved precipitating a carbon precursor (20% sucrose) on WS2 nanotubes, followed by annealing treatment under an argon environment. Thanks to the presence of highly conductive and mechanically robust carbon on the outer surface, NTs-WS2@C nanocomposites show improved electrochemical performance compared with bare NTs-WS2. After 60 cycles at 80 mA g-1 current density, the cells display high capacities of 305 mAh g-1 in LIBs and 152 mAh g-1 in SIBs, respectively. As the current density increases to 600 mA g-1, it provides specific capacities of 209 and 115 mAh g-1, correspondingly. The enhanced electrochemical performance in LIBs and SIBs is primarily attributed to the synergistic effects of the tubular architecture of WS2, carbon network and stable nanocomposite structure, which can effectively constrain volume variation during the metal ions intercalation/deintercalation processes.

Mesoscopic sliding ferroelectricity enabled photovoltaic random access memory for material-level artificial vision system.

Intelligent materials with adaptive response to external stimulation lay foundation to integrate functional systems at the material level. Here, with experimental observation and numerical simulation, we report a delicate nano-electro-mechanical-opto-system naturally embedded in individual multiwall tungsten disulfide nanotubes, which generates a distinct form of in-plane van der Waals sliding ferroelectricity from the unique combination of superlubricity and piezoelectricity. The sliding ferroelectricity enables programmable photovoltaic effect using the multiwall tungsten disulfide nanotube as photovoltaic random-access memory. A complete "four-in-one" artificial vision system that synchronously achieves full functions of detecting, processing, memorizing, and powering is integrated into the nanotube devices. Both labeled supervised learning and unlabeled reinforcement learning algorithms are executable in the artificial vision system to achieve self-driven image recognition. This work provides a distinct strategy to create ferroelectricity in van der Waals materials, and demonstrates how intelligent materials can push electronic system integration at the material level.

Nanotubes from Ternary WS2(1-x)Se2x Alloys: Stoichiometry Modulated Tunable Optical Properties.

Nanotubes of transition metal dichalcogenides such as WS2 and MoS2 offer unique quasi-1D properties and numerous potential applications. Replacing sulfur by selenium would yield ternary WS2(1-x)Se2x (0 ≤ x ≤ 1; WSSe) nanotubes, which are expected to reveal strong modulation in their absorption edge as a function of selenium content, xSe. Solid WO2.72 oxide nanowhiskers were employed as a sacrificial template to gain a high yield of the nanotubes with a rather uniform size distribution. Though sulfur and selenium belong to the same period, their chemical reactivity with oxide nanowhiskers differed appreciably. Here, the closed ampoule technique was utilized to achieve the completion of the solid-vapor reaction in short time scales instead of the conventional flow reactor method. The structure and chemical composition of the nanotubes were analyzed in detail. X-ray and electron diffractions indicated a systematic modulation of the WSSe lattice upon increasing the selenium content. Detailed chemical mapping showed that the sulfur and selenium atoms are distributed in random positions on the anion lattice site of the nanotubes. The optical excitonic features and absorption edges of the WSSe nanotubes do not vary linearly with the composition xSe, which was further confirmed by density functional theory calculations. The WSSe nanotubes were shown to exhibit strong light-matter interactions forming exciton-polariton quasiparticles, which was corroborated by finite-difference time-domain simulations. Transient absorption analysis permitted following the excited state dynamics and elucidating the mechanism of the strong coupling. Thus, nanotubes of the ternary WSSe alloys offer strong band gap tunability, which would be useful for multispectral vision devices and other optoelectronic applications.

Size and Shape's Effects on the High-Pressure Behavior of WS2 Nanomaterials.

Exploring the behavior of nanocrystals with varying shapes and sizes under high pressure is crucial to understanding the relationship between the morphology and properties of nanomaterials. In this study, we investigated the compression behaviors of WS2 nanotubes (NT-WS2) and fullerene-like nanoparticles (IF-WS2) by in situ high-pressure X-ray diffraction (XRD) and Raman spectroscopy. It was found that the bulk modulus of NT-WS2 is 81.7 GPa, which is approximately twice as large as that of IF-WS2 (46.3 GPa). This might be attributed to the fact that IF-WS2 with larger d-spacing along the c-axis and higher defect density are more compressible under isotropic pressure than NT-WS2. Thus, the slender NT-WS2 possess a more stable crystal structure than the IF-WS2. Our findings reveal that the effects of morphology and size play crucial roles in determining the high-pressure properties of WS2 nanoparticles, and provide significant insight into the relationship between structure and properties.

Nanotubes from the Misfit Layered Compound (SmS)1.19TaS2: Atomic Structure, Charge Transfer, and Electrical Properties.

Misfit layered compounds (MLCs) MX-TX2, where M, T = metal atoms and X = S, Se, or Te, and their nanotubes are of significant interest due to their rich chemistry and unique quasi-1D structure. In particular, LnX-TX2 (Ln = rare-earth atom) constitute a relatively large family of MLCs, from which nanotubes have been synthesized. The properties of MLCs can be tuned by the chemical and structural interplay between LnX and TX2 sublayers and alloying of each of the Ln, T, and X elements. In order to engineer them to gain desirable performance, a detailed understanding of their complex structure is indispensable. MLC nanotubes are a relative newcomer and offer new opportunities. In particular, like WS2 nanotubes before, the confinement of the free carriers in these quasi-1D nanostructures and their chiral nature offer intriguing physical behavior. High-resolution transmission electron microscopy in conjunction with a focused ion beam are engaged to study SmS-TaS2 nanotubes and their cross-sections at the atomic scale. The atomic resolution images distinctly reveal that Ta is in trigonal prismatic coordination with S atoms in a hexagonal structure. Furthermore, the position of the sulfur atoms in both the SmS and the TaS2 sublattices is revealed. X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and X-ray absorption spectroscopy are carried out. These analyses conclude that charge transfer from the Sm to the Ta atoms leads to filling of the Ta 5d z 2 level, which is confirmed by density functional theory (DFT) calculations. Transport measurements show that the nanotubes are semimetallic with resistivities in the range of 10-4 Ω·cm at room temperature, and magnetic susceptibility measurements show a superconducting transition at 4 K.

Poly(L-lactic acid) Reinforced with Hydroxyapatite and Tungsten Disulfide Nanotubes.

Poly(L-lactic acid) (PLLA) is a biocompatible, biodegradable, and semi-crystalline polymer with numerous applications including food packaging, medical implants, stents, tissue engineering scaffolds, etc. Hydroxyapatite (HA) is the major component of natural bone. Conceptually, combining PLLA and HA could produce a bioceramic suitable for implants and bone repair. However, this nanocomposite suffers from poor mechanical behavior under tensile strain. In this study, films of PLLA and HA were prepared with small amounts of nontoxic WS2 nanotubes (INT-WS2). The structural aspects of the films were investigated via electron microscopy, X-ray diffraction, Raman microscopy, and infrared absorption spectroscopy. The mechanical properties were evaluated via tensile measurements, micro-hardness tests, and nanoindentation. The thermal properties were investigated via differential scanning calorimetry. The composite films exhibited improved mechanical and thermal properties compared to the films prepared from the PLLA and HA alone, which is advantageous for medical applications.

Asymmetric misfit nanotubes: Chemical affinity outwits the entropy at high-temperature solid-state reactions.

Asymmetric two-dimensional (2D) structures (often named Janus), like SeMoS and their nanotubes, have tremendous scope in material chemistry, nanophotonics, and nanoelectronics due to a lack of inversion symmetry and time-reversal symmetry. The synthesis of these structures is fundamentally difficult owing to the entropy-driven randomized distribution of chalcogens. Indeed, no Janus nanotubes were experimentally prepared, so far. Serendipitously, a family of asymmetric misfit layer superstructures (tubes and flakes), including LaX-TaX2 (where X = S/Se), were synthesized by high-temperature chemical vapor transport reaction in which the Se binds exclusively to the Ta atoms and La binds to S atoms rather than the anticipated random distribution. With increasing Se concentration, the LaS-TaX2 misfit structure gradually transformed into a new LaS-TaSe2-TaSe2 superstructure. No misfit structures were found for xSe = 1. These counterintuitive results shed light on the chemical selectivity and stability of misfit compounds and 2D alloys, in general. The lack of inversion symmetry in these asymmetric compounds induces very large local electrical dipoles. The loss of inversion and time-reversal symmetries in the chiral nanotubes offers intriguing physical observations and applications.

Probing the Chiral Domains and Excitonic States in Individual WS2 Tubes by Second-Harmonic Generation.

Distinct from carbon nanotubes, transition-metal dichalcogenide (TMD) nanotubes are noncentrosymmetric and polar and can exhibit some intriguing phenomena such as nonreciprocal superconductivity, chiral shift current, bulk photovoltaic effect, and exciton-polaritons. However, basic characterizations of individual TMD nanotubes are still quite limited, and much remains unclear about their structural chirality and electronic properties. Here we report an optical second-harmonic generation (SHG) study on multiwalled WS2 nanotubes on a single-tube level. As it is highly sensitive to the crystallographic symmetry, SHG microscopy unveiled multiple structural domains within a single WS2 nanotube, which are otherwise hidden under conventional white-light optical microscopy. Moreover, the polarization-resolved SHG anisotropy patterns revealed that different domains on the same tube can be of different chirality. In addition, we observed the excitonic states of individual WS2 nanotubes via SHG excitation spectroscopy, which were otherwise difficult to acquire due to the indirect band gap of the material.

Strong, tough and bio-degradable polymer-based 3D-ink for fused filament fabrication (FFF) using WS2 nanotubes.

WS2 inorganic nanotubes (WS2-NT) have been incorporated into Polylactic Acid (PLA) by melt mixing to create a bio-degradable, mechanically reinforced nanocomposite filament. The filament was then processed by Fused Filament Fabrication (FFF) 3D-printer, and the morphology and characteristics before and after printing were compared. We found that addition of WS2-NT to PLA by extrusion mixing increases the elastic modulus, yield strength and strain-at-failure by 20%, 23% and 35%, respectively. Moreover, we found that the printing process itself improves the dispersion of WS2-NT within the PLA filament, and does not require changing of the printing parameters compared to pure PLA. The results demonstrate the advantage of WS2-NT as reinforcement specifically in 3D-printable polymers, over more traditional nano-reinforcements such as graphene and carbon nanotubes. WS2-NT based 3D-printable nanocomposites can be used for variety of applications from custom-made biodegradable scaffold of soft implants such as cartilage-based organs and biodegradable soft stents to the more general easy-to-apply nano-reinforced polymers.

YS-TaS2 and YxLa1-xS-TaS2 (0 ≤ x ≤ 1) Nanotubes: A Family of Misfit Layered Compounds.

We present the analysis of a family of nanotubes (NTs) based on the quaternary misfit layered compound (MLC) YxLa1-xS-TaS2. The NTs were successfully synthesized within the whole range of possible compositions via the chemical vapor transport technique. In-depth analysis of the NTs using electron microscopy and spectroscopy proves the in-phase (partial) substitution of La by Y in the (La,Y)S subsystem and reveals structural changes compared to the previously reported LaS-TaS2 MLC-NTs. The observed structure can be linked to the slightly different lattice parameters of LaS and YS. Raman spectroscopy and infrared transmission measurements reveal the tunability of the plasmonic and vibrational properties. Density-functional theory calculations showed that the YxLa1-xS-TaS2 MLCs are stable in all compositions. Moreover, the calculations indicated that substitution of La by Sc atoms is electronically not favorable, which explains our failed attempt to synthesize these MLC and NTs thereof.