MoS2 Quantum Research Articles

CRISPR-Cas12a-regulated DNA adsorption on MoS2 quantum dots: Enhanced enzyme mimics for sensitive colorimetric detection of human monkeypox virus and human papillomavirus DNA

Diseases caused by viruses, such as monkeypox virus (MPXV) and human papillomavirus (HPV), pose serious threats to human health and safety. Although numerous strategies have been constructed for detecting MPXV and HPV DNA, most methods require either laborious procedures or complicated instruments involving skilled professionals. In this research, a CRISPR-Cas12a-mediated colorimetric detection platform for MPXV and HPV sensing was constructed for the first time by applying probe DNA to reprogram the catalytic properties of molybdenum disulfide quantum dots (MoS2 QDs). In the presence of MPXV or HPV targets, the CRISPR-Cas12a trans-cleavage activity is effectively motivated to decompose the probe DNA, leading to the suppression of enzymatic activity DNA enhancer adsorbed on MoS2 QDs, resulting in greatly decreased catalytic behaviors. The MoS2 QDs-DNA nanohybrids displayed prominent specificity and sensitivity, with detection limits at subpicomolar levels, as well as excellent stability and accuracy for determining MPXV and HPV DNA in human sera biosamples. Furthermore, the proposed colorimetric biosensing approach can be ensembled with a smartphone platform, allowing visible analysis of DNA targets. Taken together, this colorimetric strategy offers a novel diagnosis method for MPXV and HPV DNA detection, particularly favorable for highly endemic developing countries with restricted medical and instrumental support.

Photoluminescent MoS2 quantum dots surrounded by nucleotides: an experimental and theoretical study

Photoluminescent MoS2 quantum dots surrounded by nucleotides: an experimental and theoretical study

Formamidinium lead iodide perovskite photovoltaics with MoS2 quantum dots

We present the formation of a composite film made out of formamidinium lead iodide (FAPI) and molybdenum disulphide quantum dots (MoS2 QDs) and propose a corresponding photovoltaic device architecture based on a ‘type-I’ alignment of the two materials’ electronic energy levels. The introduction of the MoS2 QDs has not compromised the overall crystallinity of the FAPI film and the composite absorber has shown improved stability. We report on the benefits of this composite film and energy band arrangement as the photogenerated carriers in MoS2 QDs, both positive and negative, are injected into the FAPI host matrix, resulting in an increased current density of 24.19 mA cm−2 compared to a current density of 19.83 mA cm−2 for the control device with FAPI only. The corresponding photoconversion efficiency increases from 12.6 to 15.0%. We also show that inclusion of MoS2 QDs in FAPI films resulted in a notable improvement in the fill factor and open-circuit voltage of the solar cells. Most importantly, MoS2 QDs enhanced the film stability by reducing defect formation and acting as passivating agents that minimize recombination losses and improve charge carrier transport. Our results suggest that a composite film in a type-I device architecture can introduce benefits for both future developments in perovskite solar cells and effectively tackling the longstanding challenges of carrier transport in QDs solar cells.

L-cysteine capped MoS2 QDs for dual-channel imaging and superior Fe3+ ion sensing in biological systems.

MoS2 quantum dots (MQDs) with an average size of 1.9 ± 0.7 nm were synthesized using a microwave-assisted method. Absorbance studies confirmed characteristic transitions of MoS2, with absorption humps at 260-280 nm and 300-330 nm, and a band gap of 3.6 ± 0.1 eV. Fluorescence emission studies showed dominant blue and some green emissions under 315 nm excitation, with an absolute quantum yield of ∼9%. The MQDs exhibited fluorescence stability over time after repeated quenching cycles across various pH and media systems. In vitro toxicity tests indicated cytocompatibility, with around 80% cell survival at 1000 mg L-1. Confocal imaging demonstrated significant uptake and vibrant fluorescence in cancerous and non-cancerous cell lines. The MQDs showed strong selectivity towards Fe3+ ions, with a detection limit of 27.61 ± 0.25 nM. Recovery rates for Fe3+ in phosphate buffer saline (PBS) and simulated body fluid (SBF) systems were >97% and >98%, respectively, with a relative standard deviation (RSD) within 3%, indicating precision. These findings suggest that MQDs have high potential for diagnostic applications involving Fe3+ detection due to their fluorescence stability, robustness, enhanced cell viability, and dual-channel imaging properties.

Building 3D Crosslinked Graphene-MXene Nanoarchitectures Decorated with MoS2 Quantum Dots Enables Efficient Electrocatalytic Hydrogen Evolution.

Although MoS2 quantum dots with abundant edge sites have been regarded as promising eletrode materials for the hydrogen evolution reaction (HER), their electrocatalytic capacity still requires improvements in actual applications. Herein. we demonstrate a controllable and robust bottom-up approach to build 3D crosslinked graphene-Ti3C2Tx MXene frameworks decorated with MoS2 quantum dots (MQD/RGO-MX) via a convenient co-assembly process. The novel structural design gives the MQD/RGO-MX nanoarchitectures a series of superior textural attributes, including 3D interconnected networks, continuous meso- and macropores, well-dispersed quantum dots, ameliorative electronic configuration, and excellent electrical conductivity. Accordingly, the resulting hybrid nanoarchitectures express superior electrocatalytic properties in terms of a low onset potential of only 45 mV, a small Tafel slope of 61 mV dec-1 as well as a long service life towards the HER, which make it quite competitive against bare MoS2 quantum dots, MXene as well as binary MQD/RGO and MQD/MXene electrocatalysts.

Quantum Confinement and End-Sealing Effects for Highly Sensitive and Stable Nitrogen Dioxide Detection: Homogeneous Integration of Ti3C2Tx-Based Flexible Gas Sensors.

The real-time and room-temperature detection of nitrogen dioxide (NO2) holds significant importance for environmental monitoring. However, the performance of NO2 sensors has been hampered by the trade-off between the high sensitivity and stability of conventional sensitive materials. Here, we present a novel fully flexible paper-based gas sensing structure by combining a homogeneous screen-printed titanium carbide (Ti3C2Tx) MXene-based nonmetallic electrode with a MoS2 quantum dots/Ti3C2Tx (MoS2 QDs/Ti3C2Tx) gas-sensing film. These precisely designed gas sensors demonstrate an improved response value (16.3% at 5 ppm) and a low theoretical detection limit of 12.1 ppb toward NO2, which exhibit a remarkable 3.5-fold increase in sensitivity compared to conventional Au interdigital electrodes. The outstanding performance can be attributed to the integration of the quantum confinement effect of MoS2 QDs and the conductivity of Ti3C2Tx, establishing the main active adsorption sites and enhanced charge transport pathways. Furthermore, an end-sealing effect strategy was applied to decorate the defect sites with naturally oxygen-rich tannic acid and conductive polymer, and the formed hydrogen bonding network at the interface effectively mitigated the oxidative degradation of the Ti3C2Tx-based gas sensors. The exceptional stability has been achieved with only a 1.8% decrease in response over 4 weeks. This work highlights the innovative design of high-performance gas sensing materials and homogeneous gas sensor techniques.

Design and understanding of SnO2 architecture decorated by MoS2 quantum dots for enhancing triethylamine sensing

The size effect through quantum dots is an effective method to improve the performance of gas sensors. This paper reports the design of a triethylamine sensor based on a SnO2-MoS2 heterojunction structure. The porous SnO2 was synthesized using a polystyrene microsphere template and then loaded with MoS2 quantum dots (MoS2 QDs) by the impregnation method. The gas-sensitizing properties of the prepared sensors were systematically investigated. Compared with the single SnO2 and MoS2 gas sensing materials, the SnO2-MoS2 sensor showed higher selectivity to triethylamine at the optimal operating temperature of 160 °C, and the response performance was improved by 192%. The results show that the SnO2-MoS2 heterojunction improves the sensing performance due to its unique pore structure, oxygen vacancies and n-n heterojunction. In addition, the energy band structure and triethylamine sensing mechanism of SnO2-MoS2 heterojunctions were analyzed by density functional theory. This work provides significant value for the study of gas-sensitive properties and triethylamine sensors of SnO2 -MoS2 QDs composites.

Optical memcapacitor based on MoS2 quantum capacitance

It is imperative to study neuromorphic devices where the behavior of artificial synapses is regulated by external conditions. The quantum capacitance of 2D materials is determined by the local density of states near the Fermi level and usually exhibits a sensitive response to external stimuli. This study explores the use of MoS2 quantum capacitance in a memcapacitor (MoS2 quantum memcapacitor, MQM), emulating biological synapse behavior and showcasing higher sensitivity. Notably, without altering the physical structure, MQM realizes the potentiation and depression of capacitance through light and gas coupling manipulation, establishing a memory effect for the device. This enables MQM to reproduce the learning-forgetting cycle multiple times with good repeatability. Moreover, MQM can simulate various biological synaptic behaviors, encompassing short-term memory to long-term memory conversions, short-term depression to long-term depression conversions, and higher pair-pulse-facilitation behavior. These characteristics offer a fresh direction and possibilities for artificial synaptic device research.

Nitrogen-doped MoS2 QDs as fluorescent probes for sensitive detection of curcumin and cell imaging

BackgroundCurcumin has been used in traditional medicine because of its pharmacological activity, including antioxidant, antibacterial, anticancer, and anticarcinogenic properties. Therefore, sensitive and selective monitoring of curcumin is highly demand for practical application. ResultsIn this study, we describe the construction of a fluorescence method for curcumin assay based on nitrogen-doped MoS2 quantum dots (N–MoS2 QDs). The N–MoS2 QDs are constructed by a solvothermal method using sodium molybdate and Cys as precursors. With the addition of curcumin, the bright blue fluorescence of N–MoS2 QDs is quenched by the inner filter effect (IFE). The QDs emitted bright blue fluorescence and could be quenched by the addition of curcumin via IFE. The dynamic range is the range of 0.1–10 μM for curcumin detection, with a detection limit of 59 nM. N–MoS2 QDs were applied for curcumin assay in real samples with good recovery. In addition, the N–MoS2 QDs exhibited relative low cytotoxicity and could be applied for fluorescence-based imaging in biological samples. SignificanceOur study indicates that the sensor possesses good selectivity to monitor curcumin in water samples, human urine samples, ginger powder samples, mustard samples, and curry samples with satisfactory recoveries. The N–MoS2 QDs possess less cytotoxicity with excellent biocompatibility and were applied for in vitro cell imaging.

A high-performance TFN membrane prepared by a novel PE support layer, a polydopamine interlayer, and a doped MoS2 quantum dots@ZnO nanocomposites-incorporated polyamide active layer

Herein, thin film nanocomposite (TFN) membranes were prepared with excellent chemical stability and separation performance for organic solvent nanofiltration (OSN) applications. The support membrane was synthesized via a new approach, in which a blend of two immiscible polymers, i.e. high density polyethylene (HDPE)-polystyrene (PS), which were compatibilized with styrene-ethylene-butylene-styrene (SEBS), was prepared through mixing by a Brabender, followed by fabricating blend sheets through a hot press machine. The PE support was then prepared by extracting the PS/compatibilizer phase from the blend sheet. The hydrophilicity of the PE support membrane was considerably enhanced with a polydopamine (PDA) layer. Different nanoparticles including nanoflower (NF) ZnO, nanosphere (NS) ZnO, MoS2 Quantum dots-nanoflower ZnO nanocomposite (QDs@NF ZnO), and MoS2 Quantum dots-nanosphere ZnO nanocomposite (QDs@NS ZnO) were incorporated into the polyamide (PA) active layer of the membranes to enhance the performance of the TFN membranes. The separation performance of the TFN membranes was investigated for rejecting different dyes dissolved in methanol. Our results demonstrate outstanding separation performance, with a dye rejection of 99.6 %, 99.6 %, 99.8 %, and 99.9 % for methylene blue, crystal violet, rhodamine B, and methyl green, respectively. Additionally, the TFN membranes incorporated with QDs@NF ZnO nanoparticles showed great solvent resistance, with a methanol permeance up to 6.7 L/m2.h.bar after activation with dimethylformamide.

Organo‐Soluble Colloidal MoS2 Quantum Dots (QDs) as an Efficient Photocatalyst for α‐Amino Phosphonate Synthesis

Abstractα‐Amino phosphonates are bio‐isosteres of amino acids and have numerous biochemical activities. While they are generally prepared via carbon–phosphorus bond formation using a plethora of methods but using recyclable photo‐catalysts and readily accessible amine and phosphites are not commonly used in synthesis. Herein, we used organo‐soluble MoS2 Quantum Dots (QDs) as an exceptionally efficient nano‐photocatalyst for the synthesis of α‐amino phosphonates. Our approach emphasizes on photocatalysis within organic media, providing a facile and effective method for conducting these intricate organic conversions under mild conditions. This straightforward process harnesses the power of molecular oxygen (O2) as an oxidizing agent. To elaborate, our method is intricately guided by the inherent capability of MoS2 QDs to enter an excited state upon absorption of blue light. This excited state bears appropriate potential energy to initiate the formation of reactive iminium ion species from N‐phenyl benzylamine, thus driving the desired product formation. Mechanistic analysis has also unveiled the pivotal role of MoS2 QDs in generating reactive superoxide radicals from O2 through single electron transfer (SET), underscoring their significance in the process. Remarkably, this photocatalytic transformation furnishes a diverse array of functionalized products, expanding its applicability and potential implications in various contexts.

Elucidating the Role of Electron Transfer in the Photoluminescence of MoS2 Quantum Dots Synthesized by fs-Pulse Ablation.

Herein, MoS2 quantum dots (QDs) with controlled optical, structural, and electronic properties are synthesized using the femtosecond pulsed laser ablation in liquid (fs-PLAL) technique by varying the pulse width, ablation power, and ablation time to harness the potential for next-generation optoelectronics and quantum technology. Furthermore, this work elucidates key aspects of the mechanisms underlying the near-UV and blue emissions the accompanying large Stokes shift, and the consequent change in sample color with laser exposure parameters pertaining to MoS2 QDs. Through spectroscopic analysis, including UV-visible absorption, photoluminescence, and Raman spectroscopy, we successfully unraveled the mechanisms for the change in optoelectronic properties of MoS2 QDs with laser parameters. We realize that the occurrence of a secondary phase, specifically MoO3-x, is responsible for the significant Stokes shift and blue emission observed in this QD system. The primary factor influencing these activities is the electron transfer observed between these two phases, as validated by excitation-dependent photoluminescence and XPS and Raman spectroscopies.

MAA Encapsulated MoS2 Quantum Dots as a Fluorescent Probe for the Sensing of Flavonoid

Transition metal dichalcogenide (TMDs) quantum dots (QDs) have attracted widespread attention among scientific community as fluorescent nanomaterial. Among TMDs, MoS2 has received particular interest due to its novel and intriguing optical properties. In this work hydrothermal method is used to prepare aqueous soluble MoS2 QDs using Molybdenyl acetylacetonate and thiourea as Mo and S precursors, respectively. The solubility of unfunctionalized MoS2 is poor in water and organic solvent, therefore thioglycolic acid is used as surfactant for surface functionalization and to enhance the aqueous solubility & stability. These functionalized QDs have been synthesized at pH 11 using hydrothermal method and explored their structural and optical properties. The as synthesized QDs are characterized using TEM, XRD, FTIR, UV-Vis and PL spectroscopy. The morphological shape of as prepared QDs is spherical with size 4-6.5 nm. The MAA encapsulated MoS2 QDs are further explored as fluorescent probe for the sensitive sensing of flavonoid Quercetin.

Mixed-Dimensional van der Waals Heterostructure (2D ReS2/0D MoS2 Quantum Dots)-Based Broad Spectral Range with Ultrahigh-Responsive Photodetector.

The remarkable properties of two-dimensional (2D) materials have led to significant advancements in photodetection and optoelectronics research. Currently, there are many successful methods that are employed to improve the responsivity of photodetectors, but the limited spectral range of the device remains a limitation. This work demonstrates the development of a mixed-dimensional (2D/0D) hybrid photodetector device fabricated using chemical vapor deposition (CVD)-grown monolayer ReS2 and solution-processed MoS2 quantum dots (QDs). The mixed dimensionality of 2D (ReS2) and zero-dimensional (0D) MoS2 QDs assist in improving the spectral range of the device [ultraviolet (360 nm) to near-infrared (780 nm)]. Further, due to the work function difference between ReS2 and MoS2 QDs, the built-in electric field across the mixed-dimensional interface promotes effective charge separation and migration, resulting in improved responsivities of the device. The calculated responsivities of the fabricated photodetector are 5.4 × 102, 3.3 × 102, and 2.6 × 102 A/W when subjected to visible, UV, and NIR light illumination, which is remarkable when compared to the existing reports on broadband photodetection. The mixed-dimensionality heterostructure coupled with contact engineering paves the way for highly responsive broadband photodetectors for potential applications in security, healthcare, etc.

1 T@2H-phase MoS2 quantum dot-modified oxygen-rich vacant ZnO for the photo-reduction of uranium without sacrificial agents

Efficient and stable photocatalytic materials are urgently needed for the photo-reduction of uranium in wastewater treatment without the addition of external sacrificial agents under air conditions. Herein, we designed and synthesized 1 T@2H MoS2 QDs (MSQ) modified oxygen-rich defective ZnO photocatalysts 1 T@2H MoS2 QDs/OV-ZnO (MSQVZO) and systematically investigated its photocatalytic U(VI) activity in various matrices, which exhibited 97 % removal efficiency of uranium after 40 min of visible light irradiation under aerobic conditions, and the order of photocatalytic activity was MSQVZO > OV-ZnO > ZnO. XRD, ESR, XPS, and UV–vis were used for the characterization of the materials. In addition, it was argued using DFT analysis that the introduction of oxygen defects drove the OV-ZnO to interact with the intermediates of the oxygen evolution reaction (OER) reaction more readily than the ZnO, thus improving the activity of the OV-ZnO-based catalysts. More importantly, a new mechanism for photo-reduction of U(VI) was established. It provides an effective strategy for the photo-reduction of U(VI) without a sacrificial agent.

A novel photoelectrochemical self-screening aptamer biosensor based on CAU-17-derived Bi2WO6/Bi2S3 for rapid detection of quorum sensing signal molecules

Quorum sensing signal molecule is an important biomarker released by some microorganisms, which can regulate the adhesion and aggregation of marine microorganisms on the surface of engineering facilities. Thus, it is significant to exploit a convenient method that can effectively monitor the formation and development of marine biofouling. In this work, an advanced photoelectrochemical (PEC) aptamer biosensing platform was established and firstly applied for the rapid and ultrasensitive determination of N-(3-Oxodecanoyl)-l-homoserine lactone (3-O-C10-HL) released from marine fouling microorganism Ponticoccus sp. PD-2. The visible-light-driven Bi2WO6/Bi2S3 heterojunction derived from metal-organic frameworks (MOFs) CAU-17 and self-screened aptamer were employed as the photoactive materials and bioidentification elements, respectively. Appropriate amount of MoS2 quantum dots (QDs) conjugated with single-stranded DNA were introduced by hybridization to enhance the photocurrent response of the PEC biosensor. The self-screening aptamer can specifically recognize 3-O-C10-HL, accompanied by increasing the steric hindrance and forcing MoS2 QDs to leave the electrode surface, resulting in an obvious reduction of photocurrent and achieving a dual-inhibition signal amplification effect. Under the optimized conditions, the photocurrent response of PEC aptasensor was linear with 3-O-C10-HL concentration from 1 nM to 10 μM, and the detection limit was as low as 0.26 nM. The detection strategy also showed a high reproducibility, superior specificity and good stability. This work not only provides a simple, rapid and ultrasensitive PEC aptamer biosensing strategy for monitoring quorum sensing signal molecules in marine biofouling, but also broadens the application of MOFs-based heterojunctions in PEC sensors.

Photostability and visible-light-driven photoactivity enhancement of hierarchical C@ZnCdS/ZnS/MoS2

Zinc cadmium sulfide solid (Zn x Cd1−x S) related composites received great attention in photocatalytic hydrogen production because of their tunable bandgap and strong visible light absorption range. But sulfide-based metal materials commonly suffer from photo-corrosion issues. It is very important to construct the photocatalysts with high efficient activity and photostability for H2 production. Herein, we successively prepared ZnCdS/ZnS (ZCS/ZS) heterostructures, ZnCdS/ZnS/MoS2 (ZCS/ZS/M) heterostructures decorated ZCS/ZS with MoS2 quantum dots, then we obtained x-C@ZCS/ZS and x-C@ZCS/ZS/M heterostructures encapsulated ZCS/ZS and ZCS/ZS/M with carbon layer. The performance of the photocatalytic hydrogen production showed that sample 0.05-C@ZCS/ZS/M has a remarkable photocatalytic H2 evolution rate of 15.231 mmol·h−1·g−1 with noble metal-free co-catalysts. This rate was approximately 21 times higher than that of the pristine ZCS/ZS photocatalyst. The optimized sample reveals an excellent stability, without activity losses after 10 h. The improved photocatalytic activity can be attributed to the unique heterojunction structure formed by ZCS/ZS and MoS2. Additionally, the carbon films played a crucial role in providing excellent stability by spatially separating the sites for redox reactions, thereby inhibiting the recombination of photo-generated electron–hole pairs.

Progress in Electronic, Energy, Biomedical and Environmental Applications of Boron Nitride and MoS2 Nanostructures.

In this review, we examine recent progress using boron nitride (BN) and molybdenum disulfide (MoS2) nanostructures for electronic, energy, biomedical, and environmental applications. The scope of coverage includes zero-, one-, and two-dimensional nanostructures such as BN nanosheets, BN nanotubes, BN quantum dots, MoS2 nanosheets, and MoS2 quantum dots. These materials have sizable bandgaps, differentiating them from other metallic nanostructures or small-bandgap materials. We observed two interesting trends: (1) an increase in applications that use heterogeneous materials by combining BN and MoS2 nanostructures with other nanomaterials, and (2) strong research interest in environmental applications. Last, we encourage researchers to study how to remove nanomaterials from air, soil, and water contaminated with nanomaterials. As nanotechnology proceeds into various applications, environmental contamination is inevitable and must be addressed. Otherwise, nanomaterials will go into our food chain much like microplastics.

A photodetector based on p-GaN/N-MoS2 QDs heterojunction with high responsivity

Molybdenum disulfide (MoS2) is the most thoroughly investigated for photodetection applications with direct bandgap transition in low-dimensional structures, high light–matter interaction, and good carrier mobility. In this work, MoS2 quantum dots was synthesis by liquid exfoliation and characterized using scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fluorescence emission spectra (FES), UV–vis spectroscopy, and Photoluminescence (PL). The average size is ∼ 3.6 nm with strong absorption in the UV region and a band gap of 4.49 eV. Moreover, a novel structure of N- MoS2 QDs \\ p-GaN heterojunction photodetector was deposited by spray coating. The PL of N- MoS2 QDs \\ p-GaN emission spectra expanded from UV to visible light with high responsivity to the visible light of 7.06 mA W−1 and detectivity of 1.24 × 1010 jones.

A polarization-sensitive, high on/off ratio and self-powered photodetector based on Nb2CT x and Nd2CT x @MoS2

MXene two-dimensional materials have been widely used in energy storage, catalysis, sensing and other fields, Nb2C as a typical two-dimensional MXene material, its exploration in the field of optoelectronics is still in its infancy, especially Nb2C-based photodetectors are still to be developed. This paper demonstrates that two-dimensional films based on few-layer Nb2C have a photoelectric response in the wavelength range from visible to near-infrared. We have found that the light response performance can be easily adjusted by controlling the thickness of the spin-coated film, and that Nb2C photodetectors show great advantages in terms of wide bandwidth, polarization response, high switching ratio, etc. By adjusting the material concentration and sample thickness, the photocurrent can reach up to 330 nA, the switching ratio can reach 410, and the responsivity can reach 8.3 × 10−4 A W−1. In the polarization characteristic test, an extinction ratio of 7.6 can be obtained. By adjusting the content of that doped MoS2 quantum dot, the dark current can reach 7.6 × 10−13 A, and the switching ratio can reach 3 × 105, which can be increased by 700 times. The above results show that the few-layer Nb2C nanosheets can be used as optoelectronic detectors in the visible to near-infrared bands, which further broadens the application prospects of two-dimensional MXene.