Molybdenum Dichalcogenides Research Articles

Reduced Graphene Oxide Supported MoSxSe2-X Bifunctional Electrocatalysts for Electrochemical Ammonia Production from Nitrate

Ammonia (NH₃) holds significant importance across various human activities, finding applications in fertilizers, pharmaceuticals, and carbon-free energy fuel. Traditionally, NH₃ production relies on the energy-intensive Haber-Bosch process, leading to substantial CO₂ emissions. As an alternative, there's growing interest in electrochemical NH₃ production. The electrochemical nitrate reduction reaction (NO₃RR) is particularly promising due to its low energy barrier, high nitrogen source solubility, and high activity. Molybdenum dichalcogenides (Mo-based TMDs) have emerged as catalysts for electrochemical NH₃ production, leveraging their 2D structure, large surface area, and tunable electrical properties. However, Mo-based TMDs having 2H crystal structure face challenges like low electrical conductivity and high hydrogen evolution reaction (HER) activity, which competes with NH₃ production. To address this, we developed various 1T-MoSxSe2-x/rGO electrocatalysts. These catalysts exhibited a yield rate exceeding 3511.9 μg h-1 cm-2 (at -0.6 V vs. RHE) and a 70 % faradaic efficiency (at -0.2 V vs. RHE) in a 1 M KOH and 0.1 M NaNO₃ solution. And their bifunctional properties (Oxygen evolution reaction, OER) show a low overpotential of 338.8 mV at 10 mA. Our research aims to enhance NO3RR under ambient conditions and investigate the potential of bifunctional properties (OER) for the commercialization of electrochemical NH₃ production.

Unveiling the degradation mechanism of cathodic MoS2/C electrocatalysts for PEMWE applications

Molybdenum dichalcogenides (MoS2) are promising non-noble alternatives to replace platinum (Pt) for Hydrogen Evolution Reaction (HER) electrocatalysis in Proton Exchange Membrane Water Electrolyzers (PEMWE). The knowledge acquired on this class of catalyst for hydrodesulfurization (HDS) reactions has enabled significant advances in designing active MoS2 for HER. However, the stability of MoS2 in the dynamic operating conditions of a PEMWE coupled to renewable energy sources is often overlooked in the literature and is the focus of the present work. Herein, using nano slabs of 2H MoS2 supported on high surface area carbon, we dynamically monitored Mo dissolution trends both under HER conditions and at more anodic potentials to mimic start-ups and shut-downs of a PEMWE device. We report minimal Mo dissolution under HER conditions but it continuously increased with higher electrode potentials. In particular, Mo dissolution peaked during the irreversible oxidation from Mo(IV) to Mo(VI) starting at E = 0.7 VRHE which in turn fully annihilates HER activity. Since no change in Mo and S surface composition was observed, the decline in HER activity was attributed to the continuous exfoliation of the 2D MoS2 stacked layers induced by oxidation/dissolution of Mo. Additionally, our findings indicate that Mo cations can redeposit onto the cathode catalytic layer, forming a Mo blue film primarily composed of Mo(VI) species. This redeposition hampers HER performance by blocking catalytic sites and diminishing the catalyst's overall efficiency. These insights demonstrate the need to avoid excursions above E = 0.6 VRHE for the safe use of MoS2 cathode catalyst in PEMWE.

A Mini Review: Phase Regulation for Molybdenum Dichalcogenide Nanomaterials.

Atomically thin two-dimensional transition metal dichalcogenides (TMDCs) have been regarded as ideal and promising nanomaterials that bring broad application prospects in extensive fields due to their ultrathin layered structure, unique electronic band structure, and multiple spatial phase configurations. TMDCs with different phase structures exhibit great diversities in physical and chemical properties. By regulating the phase structure, their properties would be modified to broaden the application fields. In this mini review, focusing on the most widely concerned molybdenum dichalcogenides (MoX2: X = S, Se, Te), we summarized their phase structures and corresponding electronic properties. Particularly, the mechanisms of phase transformation are explained, and the common methods of phase regulation or phase stabilization strategies are systematically reviewed and discussed. We hope the review could provide guidance for the phase regulation of molybdenum dichalcogenides nanomaterials, and further promote their real industrial applications.

Janus molybdenum di-chalcogenides based van der Waals bilayers for supercapacitor electrode design- effects of interlayer stacking orientations on quantum capacitance

In this work, for the first time, the quantum capacitance of an artificial two-dimensional (2D) material system based on van der Waals (vdW) bilayer heterostructures of Janus Molybdenum Di-chalcogenides, MoXY (X≠Y, X/YS, Se, Te) have been extensively investigated for electrode design of electrical double-layer (EDL) supercapacitor. The effects of different interlayer stacking orientations on local charge distribution, interlayer charge transfer, energy band structure, and density of states (DOS) have been comprehensively analyzed and correlated with the excess charge density and quantum capacitance variation with local electrode potential. Furthermore, the total capacitance reduction with respect to EDL capacitance has been analyzed over a wide range of EDL capacitance, and the performance of vdW Janus bilayers has been systematically benchmarked against the natural monolayers/bilayers and Janus monolayers of Molybdenum Di-chalcogenides. The results demonstrate that the large interlayer charge transfer induced built-in interlayer electric field significantly reduces the energy band gap of vdW Janus bilayers for S–Te and Se–Te interlayer stacking, thus leading to a significantly superior quantum capacitance. Finally, the favorable valley-dependent effective mass and band-degeneracy in MoSTe/MoSeTe have greatly enhanced quantum capacitance in S–Te and Se–Te stacking, rendering these bilayers a highly attractive candidate for supercapacitor electrode design.

Li adsorption and diffusion on the surfaces of molybdenum dichalcogenides MoX2 (X = S, Se, Te) monolayers for lithium-ion batteries application: a DFT study.

We study some of the most high performance electrode materials for lithium-ion batteries. These comprise molybdenum dichalcogenide MoX2 (molybdenum disulfide MoS2, molybdenum diselenide MoSe2, molybdenum ditelluride MoTe2). The stability is studied by calculating cohesive energy and formation energy. Structural, electronic, and electrical properties are well defined, and these structures show a direct gap. Lithium adsorption at different sites, theoretical storage capacity, and lithium diffusion path are determined. Our study findings suggest that the adsorption of Li on the preferred site on the surface of the MoX2 monolayer maintains its semiconductor behavior. Comparing the activation energy barrier of these structures with other monolayers such as graphene or silicene, we found that MoX2 shows low lithium diffusion energy and good storage capacity, which indicates that the MoX2 is well suited as an anode material for lithium-ion batteries. Our research can offer new ideas for experimental and theoretical design and new anode materials for lithium-ion batteries (LIB). The studies were performed with Quantum ESPRESSO package based on density functional theory (DFT), plane waves, and pseudopotentials (PWSCF) to calculate the physical properties of MoX2 (X = S, Se, Te), lithium adsorption, and diffusion on their surfaces and the storage capacity of these structures. The BoltzTraP code is used to calculate thermoelectric properties.

Diverse chalcogen bonded molybdenum dichalcogenide alloy for the efficient photo- and electro-catalytic activity to eradicate the methylene blue and Congo red dyes

In recent times, metal dichalcogenides have an attractive research significance owing to their distinguishing characteristics and capability to accommodate for wide range of applications. This work demonstrated the formation of distinctive chalcogen atoms bonded molybdenum Janus alloy structures such as SMoTe, SMoSe and SeMoTe and their ability as catalysts for oxidative and photo-decay of methylene blue and Congo red dyes. The SeMoTe nanoarray structures reduced these dyes efficiently from water by oxidation, achieving 99% and 93% effectiveness after the 36 h, respectively; and splendid degradation under 120 min UV light irradiation (97% and 99%, respectively). Experimental results confirmed robust SeMoTe catalyst activity for dye photodegradation (k = 0.027 and 0.039 min−1, respectively) under UV illumination, almost double that achieved for the corresponding pure structures. The proposed novel approach to design the Janus alloy two-dimensional structure accomplishes the eco-friendly application of dye decolorization using the earth abundance materials.

SERS-based detection of efficient removal of organic dyes using molybdenum dichalcogenide nanostructures

Two-dimensional materials have been popular in recent times owing to their special properties that can lead to several applications. In particular, transition metal dichalcogenides have been reported to be potential candidates for photocatalytic degradation and adsorptive removal of organic pollutants. Molybdenum-based chalcogenides have shown to be very efficient in removing pollutant dyes from aqueous solutions. Here, we report a facile method for the removal of organic dyes from aqueous solution using molybdenum dichalcogenide (MoX2; X = S, Se, Te) based nanostructures. The molybdenum dichalcogenide nanostructures were synthesized chemically using the simple hydrothermal method. The samples were characterized by X-ray diffraction, Raman Spectroscopy, UV–visible spectroscopy, and scanning electron microscopy. The as-prepared samples have been utilized as an adsorbent for the removal of common organic dyes such as methylene blue (MB), methyl orange (MO), malachite green (MG), rhodamine B (RhB), rhodamine 6 G (R6G) and mixtures of these organic dyes from aqueous solution. It was observed that among the synthesized samples, molybdenum disulfide (MoS2) presented excellent adsorption affinity towards these dyes. In addition, selective adsorption of MB in the presence of MO and RhB was demonstrated. Furthermore, the application of surface-enhanced Raman scattering (SERS) to monitor the degradation of the dyes in the experiments was also investigated.

Exploring the experimental study and density functional theory calculations of symmetric and asymmetric chalcogen atoms interacted molybdenum dichalcogenides for lithium-ion batteries

Two-dimensional asymmetric chalcogen atoms attached to Janus nanoparticles have fascinated research attention owing to their distinctive properties and characteristics for various applications. This paper proposed a facile synthesis to produce efficient molybdenum-based symmetric and asymmetric chalcogens bounded by XMoX and TeMoX nanostructures. Subsequently, the fabricated XMoX and TeMoX nanostructures were employed as anodes for lithium-ion batteries (LIBs). Assembled LIBs using TeMoS and TeMoSe Janus anodes achieved 2610 and 2073 mAh g–1 reversible capacity at 0.1 A g–1, respectively for the half-cell configuration, which is outstanding performance compared with previous reports. Superior rate capability performances at 0.1–20 A g–1 and exceptional cycling solidity confirmed high charge and discharge capacities for TeMoX Janus lithium-ion battery anodes. In addition, the full cell device with TeMoS//LiCoO2 configuration explored the discharge capacity of 1605 mAh g−1 at 0.1 A g–1 which suggests their excellent electrochemical characteristics. The density functional theory approximations established the significance of assembled symmetric and asymmetric chalcogen atoms interacted with XMoX and TeMoX anode materials for LIBs. Thus, the present investigation supports a new approach to creating two-dimensional materials based on asymmetric chalcogen atoms with core metal to effectively increase desirable energy storage characteristics.

Theoretical investigation of the structural and electronic properties of bilayer van der Waals heterostructure of Janus molybdenum di-chalcogenides – Effects of interlayer chalcogen pairing

This work presents a two-dimensional (2D) material system of van der Waals (vdW) bilayer heterostructures between Janus Molybdenum Di-chalcogenides, MoXY (X≠Y, X/YS, Se, Te). Subsequently, using first-principle calculations, the comparative structural and electronic properties of such bilayers are comprehensively investigated. In this context, four distinct interlayer stacking orientations are identified for each Janus vdW bilayer, and the influence of interlayer chalcogen pair specifications on the electronic properties is emphasized. The structural stabilities are quantified in terms of cohesive energy and interlayer interaction energy, and the structural properties are assessed from the bond length, bond angle, interlayer distance, and Mulliken charge. Next, the electronic properties of Janus vdW bilayers are comprehensively studied from the energy band structures with their constituent monolayer as well as atomic orbital projections and the total density of states (TDOS) profiles. In this context, the energy band structure and TDOS profiles are systematically analyzed in correlation with interlayer chalcogen pair specifications. Finally, the electronic properties of Janus vdW bilayers are benchmarked against their natural homogenous bilayer counterparts.

Effects of Exchange Correlation Functional (Vwdf3) on the Structural, Elastic, and Electronic Properties of Transition Metal Dichalogenides

In this research, the effects of Van der Waals forces on the structural, elastic, electronic, and optical properties of bulk transition metals dichalcogenides (TMDs) were studied using a novel exchange-correlation functional, vdW-DF3. This new functional tries to correct the hidden Van der Waals problems which are not reported by the previous exchange functionals. Molybdenum dichalcogenide, MoX 2 (X = S, Se, Te) was chosen as a representative transition metal dichalcogenide to compare the performance of the newly designed functional with the other two popular exchange-correlation functional; PBE and rVV10. From the results so far obtained, the analysis of the structural properties generally revealed better performance by vdW-DF3 via the provision of information on lattice parameters very closer to the experimental value. For example, the lattice constant obtained by vdW-DF3 was 3.161 Å which is very close to 3.163 Å and 3.160 Å experimental and theoretical values respectively. Calculations of the electronic properties revealed good performance by vdW-DF3 functional. Furthermore, new electronic features were revealed for MoX2 (X = S, Se, Te). In terms of optical properties, PBE functional demonstrates lower absorption than vdW-DF3, as such it can be reported that vdW-DF3 improves photon absorption by TMDs. However, our results also revealed that vdW-DF3 performed well for MoS2 than for MoSe2 and MoTe2 because of the lower density observed for the S atom in MoS2.

A review of Influence of MoS2 on the tribological characteristics of diamond-like carbon coatings

Diamond-like carbon (DLC) coatings are increasingly used on machine parts due to their excellent friction and wear resistance. Therefore, it is important to formulate lubricants that can work effectively with these coatings. To do this, it is necessary to know how the various surface-reactive additives generally used in lubricants behave with DLCs. Tribological contacts (friction and wear) with solid lubricant coatings generally result in the transfer of a thin layer of material from the surface of the coating to the mating surface, commonly referred to as a transfer film or tribofilm. The wear surfaces may have different chemistry, microstructure and crystallographic texture than that of the main coating due to chemical reactions of the surface with the surrounding environment This article deals with the behavior of molybdenum dichalcogenide as a surface coating or as a filler in lubricating composites. The inherent lubricating lamellar structure of pure MoS is described, along with a brief summary of its wear and failure modes. Tribological performance of the DLC coatings, in combination with various base oils and lubricant additives, is analyzed by comparing their average friction and wear coefficient values, which have been calculated from published experimental data.

Band Alignments, Electronic Structure, and Core-Level Spectra of Bulk Molybdenum Dichalcogenides (MoS2, MoSe2, and MoTe2).

A comprehensive study of bulk molybdenum dichalcogenides is presented with the use of soft and hard X-ray photoelectron (SXPS and HAXPES) spectroscopy combined with hybrid density functional theory (DFT). The main core levels of MoS2, MoSe2, and MoTe2 are explored. Laboratory-based X-ray photoelectron spectroscopy (XPS) is used to determine the ionization potential (IP) values of the MoX2 series as 5.86, 5.40, and 5.00 eV for MoSe2, MoSe2, and MoTe2, respectively, enabling the band alignment of the series to be established. Finally, the valence band measurements are compared with the calculated density of states which shows the role of p-d hybridization in these materials. Down the group, an increase in the p-d hybridization from the sulfide to the telluride is observed, explained by the configuration energy of the chalcogen p orbitals becoming closer to that of the valence Mo 4d orbitals. This pushes the valence band maximum closer to the vacuum level, explaining the decreasing IP down the series. High-resolution SXPS and HAXPES core-level spectra address the shortcomings of the XPS analysis in the literature. Furthermore, the experimentally determined band alignment can be used to inform future device work.

Phonon mediated superconductivity in field-effect doped molybdenum dichalcogenides

Superconductivity occurs in electrochemically doped molybdenum dichalcogenides samples thicker than four layers. While the critical temperature (T c ) strongly depends on the field effect geometry (single or double gate) and on the sample (MoS2 or MoSe2), T c always saturates at high doping. The pairing mechanism and the complicated dependence of T c on doping, samples and field-effect geometry are currently not understood. Previous theoretical works assumed homogeneous doping of a single layer and attributed the T c saturation to a charge density wave instability, however the calculated values of the electron–phonon coupling in the harmonic approximation were one order of magnitude larger than the experimental estimates based on transport data. Here, by performing fully relativistic first principles calculations accounting for the sample thickness, the field-effect geometry and anharmonicity, we rule out the occurrence of charge density waves in the experimental doping range and demonstrate a suppression of one order of magnitude in the electron–phonon coupling, now in excellent agreement with transport data. By solving the anisotropic Migdal-Eliashberg equations, we explain the behavior of T c in different systems and geometries. As our first principles calculations show an ever increasing T c as a function of doping, we suggest that extrinsic mechanisms may be responsible for the experimentally observed saturating trend.

Hydrothermal preparation of MoX2 (X = S, Se, Te)/TaS2 hybrid materials on carbon cloth as efficient electrocatalyst for hydrogen evolution reaction

The prominent features-based two-dimensional (2D) materials have proven themselves as efficient as well as robust electrocatalysts for the hydrogen evolution reaction (HER) owing to their low-cost, abundance and predominant conductivity. In this work, we report the synthesis of series of molybdenum chalcogenide nanostructures MoX2 (X = S, Se, Te), hybridized with TaS2 nanosheets, via a facile hydrothermal method, on self-supported carbon cloth electrode. Used as an electrocatalyst for HER, hybrid phase MoSe2/TaS2/CC electrode with a Mo/Se ratio of 1:1.5 exhibits the best HER performance, which could afford the benchmark current densities of 10 mA/cm2 at the overpotentials of 75 mV with the measured Tafel slope values of 54.7 mV/dec. In addition, the presented molybdenum dichalcogenides in this work are also complimented with robustness as determined from durability and air stability measurements. The unique aspects of these unique hybrids, such as 1T and 2H phases hybridized MoS2 and MoSe2, semimetallic nature 1T′-MoTe2 petal clusters and strong interface interaction between MoX2 (X = S, Se, Te) and conductive TaS2 nanosheets, cause superior HER catalytic performance.

Molybdenum‐Based Nanomaterials for Photothermal Cancer Therapy

Molybdenum (Mo) is a trace dietary element that is essential for human survival. Several molybdenum‐containing enzymes (e.g., aldehyde oxidase, xanthine oxidase and sulfite oxidase) are associated with key metabolic activities in the body. Molybdenum‐based nanomaterials (Mo‐NMs), including molybdenum dichalcogenides, molybdenum oxides, molybdenum‐based polyoxometalates, and molybdenum‐based nanocomposites, have been extensively explored in biomedical applications including photothermal therapy (PTT) because of their unique chemical and physical properties as well as excellent biocompatibility and biodegradability. PTT, which relies on converting the near‐infrared (NIR) light energy into thermal energy to achieve therapeutic effects, has attracted considerable attention in past decades for cancer treatment because of its localized and trigger‐activated therapeutic effects. In this review, the state‐of‐the‐art progress on Mo‐NMs for photothermal cancer treatment is summarized. The classification, synthesis, and surface functionalization of Mo‐NMs are first introduced. Then the discussion of PTT and PTT‐combined therapies of Mo‐NMs for effective cancer treatment is focused on. Following that, the toxicity assessment of Mo‐NMs is also discussed. Finally, a short discussion on the challenges and future prospects in this field is presented.

Systematic Mapping of Electrocatalytic Descriptors for Hybrid and Non-Hybrid Molybdenum Dichalcogenides with Graphene Support for Cathodic Hydrogen Generation

For the hydrogen evolution reaction (HER) from water electrolysis, electrocatalytic performances of nanocomposites consisting of hybrid and non-hybrid molybdenum dichalcogenides with graphene (MoCh2/Gr) support (MoS2/Gr, MoSe2/Gr, MoTe2/Gr, MoSSe/Gr, MoSTe/Gr, MoSeTe/Gr, and MoS0.67Se0.67Te0.67/Gr) have been investigated both computationally and experimentally. In the computational part, hydrogen binding energetics of various adsorption sites on hybrid and non-hybrid MoCh2/Gr are elucidated with plane-wave density functional theory to evaluate the catalytic performance according to Sabatier’s principle. Near-zero values of Gibbs free energy of binding (ΔGb ≈ 0) have been considered a criterion for establishing the most catalytically active site. Moreover, electrochemical measurements revealed that all the materials, which have been synthesized through a microwave-assisted heating approach, are highly active and durable for the HER with overpotentials in the range of 127–217 mV and have negligible activity loss for 96 h of constant potential tests. Among all the different molybdenum dichalcogenide/graphene nanocomposites, the materials containing a high (≥50%) stoichiometric proportion of tellurium (Te) exhibited better HER activities compared to other chalcogens. Most importantly, hybrid nanocomposites, except the highest-entropy alloy MoS0.67Se0.67Te0.67/Gr, exhibited improved performance compared to the non-hybrid MoCh2 compounds.

Quasi‐Continuous Tuning of Carrier Polarity in Monolayered Molybdenum Dichalcogenides through Substitutional Vanadium Doping

AbstractSemiconducting 2D transition metal dichalcogenides (2D TMDs) with tunable electronic properties are a fundamental prerequisite for the development of next generation advanced electronic/optoelectronic devices. However, controllable and quasi‐continuous tuning carrier polarity of monolayered MoS2 ranging from intrinsic n‐type to p‐type via ambipolarity still remains a challenge. Herein, quasi‐continuous tailoring of carrier polarity of monolayered MoS2 through substitutional doping of molybdenum (Mo) with vanadium (V) atoms is presented. Atomic distribution in real space characterized by spherical aberration‐corrected scanning transmission electron microscopy (Cs‐STEM) reveals that the V atoms randomly substitute Mo in monolayered MoS2, and its doping concentration can be tuned in a wide range from 0.7 to ≈10 at.%. Electrical measurements confirm that the carrier polarity of the monolayered MoS2 can be tuned from intrinsic n‐type to p‐type via ambipolarity depending on the V doping degree, consistent with the density functional theory calculations. Moreover, this doping strategy is demonstrated to extend to other monolayered 2D TMDs by using MoSe2 as a model material, owing to a good universality.

Preparation of 2D Molybdenum Phosphide via Surface-Confined Atomic Substitution.

The emerging nonlayered 2D materials (NL2DMs) are sparking immense interest due to their fascinating physicochemical properties and enhanced performance in many applications. NL2DMs are particularly favored in catalytic applications owing to the extremely large surface area and low-coordinated surface atoms. However, the synthesis of NL2DMs is complex because their crystals are held together by strong isotropic covalent bonds. Here, nonlayered molybdenum phosphide (MoP) with well-defined 2D morphology is synthesized from layered molybdenum dichalcogenides via surface-confined atomic substitution. During the synthesis, the molybdenum dichalcogenide nanosheetfunctions as the host matrix where each layer of Mo maintains their hexagonal arrangement and forms isotropic covalent bonds with P that substitutes S, resulting in the conversion from layered van der Waals material to a covalently bonded NL2DM. The MoP nanosheets converted from few-layer MoS2 are single crystalline, while those converted from monolayers are amorphous. The converted MoP demonstrates metallic charge transport and desirable performance in the electrocatalytic hydrogen evolution reaction (HER). More importantly, in contrast to MoS2 , which shows edge-dominated HER performance, the edge and basal plane of MoP deliver similar HER performance, which is correlated with theoretical calculations. This work provides a new synthetic strategy for high-quality nonlayered materials with well-defined 2D morphology for future exploration.

Comparative analysis of strain engineering on the electronic properties of homogenous and heterostructure bilayers of MoX2 (X = S, Se, Te)

In this work, for the first time, the comparative electronic properties of homogenous and van der Waals (vdW) heterostructure bilayers of Molybdenum Dichalcogenides, MoX2 (X = S, Se, Te) is investigated using first-principle calculations with the emphasis on their response to applied biaxial mechanical strain. The dynamical, thermal, and energetical stability of the vdW bilayers are assessed in detail. Next, a comprehensive analysis of energy band structure with the atomic orbital projections of band edges has been performed for individual bilayers. In this context, the energy of different conduction and valence band edges are studied within a range of 5% biaxial compressive (BC) to 5% biaxial tensile (BT) strain. The applied strain-dependent band edge energy modulations are extensively analysed based on the change in structural properties and thereby the strength of in-plane and interlayer atomic orbital couplings. The analysis is further extended to correlate the variations in energy bandgaps and density of states (DOS) in different bilayers with applied strain. The results indicate that, unlike homogenous bilayers, the vdW bilayers demonstrate distinct electronic properties in their relaxed configuration. Specifically, the MoSe2/MoTe2, MoS2/MoSe2, and MoS2/MoTe2 exhibit small direct bandgap, moderate indirect bandgap, and metallic/semimetallic nature, respectively. Furthermore, distinctly different modulations in conduction band minima (CBM) and valence band maxima (VBM) positions in the Brillouin zone are observed with applied strain for individual vdW bilayers in contrast to almost similar nature of variations in CBM/VBM positions of homogenous bilayers. This leads to characteristic nonlinear variations in energy bandgap and distinct DOS modulations for individual vdW bilayers under applied strain. The key findings indicate that the suitably strained VdW bilayer MoX2 are highly promising materials for a plethora of electronic and optoelectronic applications.

Fabrication of High-Performance Solar Cells and X-ray Detectors Using MoX2@CNT Nanocomposite-Tuned Perovskite Layers.

The interface design of inorganic and organic halide perovskite-based devices plays an important role to attain high performance. The modification of transport layers (ETL and HTL) or the perovskite layer is given the crucial inspiration to realize superior power conversion efficiencies (PCEs). The highly conducting 2D materials of CNT, graphene/GO, and transition-metal dichalcogenides (TMDs) are suitable substitutes to tune the electronic structure/work function of perovskite devices. Herein, the nanocomposites composed of molybdenum dichalcogenides (MoX2 = MoS2, MoSe2, and MoTe2) stretched CNT was embedded with HTL or perovskite layer to improve the resulted characteristics of perovskite devices of solar cells and X-ray detectors. A superior solar cell efficiency of 12.57% was realized for the MoTe2@CNT nanocomposites using a modified active layer-composed device. Additionally, X-ray detectors with MoTe2@CNT-modulated active layers achieved 13.32 μA/cm2, 3.99 mA/Gy·cm2, 4.81 × 10-4 cm2/V·s, and 2.13 × 1015 cm2/V·s of CCD-DCD, sensitivity, mobility, and trap density, respectively. Density functional theory approximation was used to realize the improved electronics properties, optical properties, and energy band structures in the MoX2@CNT-doped perovskites evidently. Thus, the current research paves the way for the improvement of highly efficient semiconductor devices based on perovskite-based structures with the use of 2D nanocomposites.