Van Der Waals Interactions Research Articles

Customization of 2D Atomic-Molecular Heterojunction with Manipulatable Charge-Transfer and Band Structure.

Manipulating the properties of 2Dmaterials through meticulously engineered artificial heterojunctions holds great promise for novel device applications. However, existing research on the crucial charge-transfer interactions and energy profile regulation is predominantly focused on 2D van der Waals structures formed via weak van der Waals forces, limiting regulatory efficiency at high costs. Herein, a refined atomic-molecular heterojunction strategy featuring strong covalent bonds between organic molecule and 2D violet phosphorus (VP) atomic crystal is developed, which enables enhanced charge-transfer dynamics and customizable band structure regulation at the molecular level. Both experimentally and theoretically, it is demonstrated that grafting efficiency, charge redistribution, and energy gap regulation critically depend on organic electronegativity, providing a low-cost yet high-efficiency regulatory effect on a large scale. As a proof of concept, the novel VP-molecular heterojunctions exhibit optimized performance in diverse application domains, presenting a general platform for future high-performance device applications.

Boosting photothermal conversion through array aggregation of metalloporphyrins in bismuth-based coordination frameworks.

Materials capable of efficiently converting near-infrared (NIR) light into heat are highly sought after in biotechnology. In this study, two new three-dimensional (3D) porphyrin-based metal-organic frameworks (MOFs) with a sra-net, viz. CoTCPP-Bi/NiTCPP-Bi, were successfully synthesized. These MOFs feature bismuth carboxylate nodes interconnected by metalloporphyrinic spacers, forming one-dimensional (1D) arrays of closely spaced metalloporphyrins. Notably, the CoTCPP-Bi exhibits an approximate Co⋯C distance of 3 Å, leading to enhanced absorption of NIR light up to 1400 nm due to the presence of strong interlayer van der Waals forces. Furthermore, the spatial arrangement of the metalloporphyrins prevents axial coordination at the centers of porphyrin rings and stabilizes a CoII-based metalloradical. These characteristics promote NIR light absorption and non-radiative decay, thereby improving photothermal conversion efficiency. Consequently, CoTCPP-Bi can rapidly elevate the temperature from room temperature to 190 °C within 30 seconds under 0.7 W cm-2 energy power from 808 nm laser irradiation. Moreover, it enables solar-driven water evaporation with an efficiency of 98.5% and a rate of 1.43 kg m-2 h-1 under 1 sun irradiation. This research provides valuable insights into the strategic design of efficient photothermal materials for effective NIR light absorption, leveraging the principles of aggregation effect and metalloradical chemistry.

A Study on the Binding Mechanism and the Impact of Key Residue Mutations between SND1 and MTDH Peptide through Molecular Dynamics Simulations.

Metastasis of breast cancer is the main cause of death for patients with breast cancer. The interaction between metadherin (MTDH) and staphylococcal nuclease domain 1 (SND1) plays a pivotal role in promoting breast cancer development. However, the binding details between MTDH and SND1 remain unclear. In this study, we employed all-atom molecular dynamics simulations (MDs) and conducted binding energy calculations to investigate the binding details and the impact of key residue mutations on binding. The mutations in key residues have not significantly affected the overall stability of the structure and the fluctuation of residues near the binding site; they have exerted a substantial impact on the binding of SND1 and MTDH peptide. The electrostatic interactions and van der Waals interactions play an important role in the binding of SND1 and the MTDH peptide. The mutations in the key residues have a significant impact on electrostatic and van der Waals interactions, resulting in weakened binding. The energy contributions of key residues mainly come from the electrostatic energy and van der Waals interactions of the side chain. In addition, the key residues form an intricate and stable network of hydrogen bonds and salt-bridge interactions with the MTDH peptide. The mutations in key residues have directly disrupt the interactions formed between SND1 and MTDH peptide, consequently leading to changes in the binding mode of the MTDH peptide. These analyses unveil the detailed atomic-level interaction mechanism between SND1 and the MTDH peptide, providing a molecular foundation for the development of antibreast cancer drugs.

Investigation of the Nonradiative Photoprocesses of Unnatural DNA Base: 7-(2-Thienyl)-imidazo[4,5-b]pyridine (Ds)─A Computational Study.

7-(2-Thienyl)-imidazo[4,5-b]pyridine (Ds) is an unnatural nucleic acid that forms a stable pair with pyrrole-2-carbaldehyde (Pa) in DNA. This Ds-Pa pair gets stabilized via van der Waals interaction and shape fitting. In our previous study [Ghosh, P. J. Phys. Chem. A 2021, 125, 5556-5561], we investigated the nonradiative photoprocesses of the unnatural DNA base Pa, and also there are some studies on its stability and reactivity in the ground state. But, to consider it as a good unnatural base pair, one has to understand its stability not only in the ground state but also in the excited states after absorbing ultraviolet (UV) radiation. Therefore, in this study, the excited-state photoprocesses of Ds on UV irradiation and its nonradiative decay channels have been investigated using state-of-the-art multireference methods, and this investigation finally leads the molecule to access the minimum energy crossing point (MECP) via a downhill pathway.

Molecular mechanism of immunotoxicity: Binding interaction between perfluorinated compounds and human immunoglobulin G

Perfluorinated compounds (PFCs) can induce immunotoxicity effect via binding with proteins. Immunoglobulin G (IgG) is a common four chain monomer protein in serum, and plays an important role in long-term body fluid immunity. Whether PFCs can bind with IgG and further induce immunotoxicity is not clear. Herein, fluorescence quenching assay was used to verify the PFCs-IgG binding interactions. The occurrence of fluorescence quenching phenomenon suggested that PFCs could bind to IgG. Linear fitting curves demonstrated that the binding constants (KA) for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) were 2.51 × 106 L/mol and 1.58 × 105 L/mol, respectively. UV–vis spectral analysis results showed that the PFCs-IgG interactions mainly proceeded via the intercalation binding mode. Fourier transform infrared spectroscopy results revealed that PFCs preferentially bound to the C=O/N-H of IgG structure. Circular dichroism results revealed that PFCs-IgG binding induced the decrease of α-helix. Moreover, hydrogen bonds and van der Waals force dominated PFCs-IgG binding interactions. This binding process was a stable process, and its stability depended on the number of hydrogen bonds formation. This study reveals the mechanism of interaction between PFCs and IgG at the molecular level, providing a theoretical basis for the immunotoxic mechanism of PFCs.

Multichannel Carbon Nanofibers: Pioneering the Future of Energy Storage.

Multichannel carbon nanofibers (MCNFs), characterized by complex hierarchical structures comprising multiple channels or compartments, have attracted considerable attention owing to their high porosity, large surface area, good directionality, tunable composition, and low density. In recent years, electrospinning (ESP) has emerged as a popular synthetic technique for producing MCNFs with exceptional properties from various polymer blends, driven by phase separation between polymers. These interactions, including van der Waals forces, covalent bonding, and ionic interactions, are crucial for MCNF production. Over time, the applications of MCNFs have expanded, making them one of the most intriguing topics in material research. MCNFs with tailored porous channels, controllable dimensions, confined spaces, high surface areas, designed architectures, and easy electrolyte access to active walls are considered optimal for electrochemical energy storage (EES) technologies. This review provides an exhaustive overview of the working principle, synthesis methods, and structural properties of MCNFs, and examines their advantages, limitations, and potential for producing multichannel architectures. Furthermore, this review explores the relationship between the composition of MCNF electrode materials for EES devices (supercapacitors and batteries) and their electrochemical performance. This review also addresses future directions and challenges in the development and utilization of MCNFs and provides insights into potential research avenues for advancing this exciting field.

Integrating strategy to investigate the formation and stabilization mechanisms of Curcumin-Cyclodextrin inclusion complexes: experimental characterizations and multi-scale computational simulations.

The Cyclodextrin (CD) encapsulation technology can significantly enhance the water solubility of Curcumin (CUR) and effectively protect it against chemical degradations. In the current study, a combination of experimental and multi-scale computational approaches was used to investigate the binding mechanism between CUR and β-CDs (β-CD, 2-HP-β-CD, Me-β-CD, and DM-β-CD). Phase solubility studies showed that β-CDs exhibited a strong binding affinity with CUR and significantly enhanced its solubility. SEM, PXRD, DSC, and TG analysis confirmed the formation of inclusion complexes, resulting in the transition of CUR from crystalline to an amorphous state. FTIR, 1H, and 13CNMR spectra deduced that CUR may have multiple binding conformations with β-CDs. The rationality of molecular dynamics simulation systems was confirmed by comparing the simulated IR spectrum from quantum mechanics with the experimental IR spectrum. MM-PBSA and umbrella sampling simulation calculated the binding free energy of the CUR/CD inclusion complexes, ranking Me-β-CD > DM-β-CD > 2-HP-β-CD > β-CD, and clarified that van der Waals interaction played a major role in stabilizing the inclusion complexes. RDF analysis confirmed that the release of high-energy water molecules drove the formation of the CUR/CD inclusion complex, and the β-CD substituents affected their exterior hydration layer. Additionally, principal component analysis (PCA) and non-covalent interaction analysis revealed three CUR/CD binding modes: bead-on-string, terminal insertion, and V-shaped-folding. The research strategy adopted here can serve as a paradigm for investigating the encapsulation mechanism of poorly soluble drugs with CDs.

The regulatory mechanism of mannan from millet Huangjiu on flavor release

Huangjiu, the national wine of China, has the characteristics of low grain consumption, low alcohol content and high nutrition, which aligns with the world's beverage wine consumption trend. The research on glutinous rice huangjiu from southern China is more extensive, while millet huangjiu from northern China has received less attention, hindering the diversified development of huangjiu. Polysaccharides play an important role in huangjiu's health activity and flavor characteristics. In this study, the polysaccharide components in millet huangjiu were separated and identified for the first time, and the influence of polysaccharides on the flavor release was explored through sensory evaluation, SPME-GC–MS, threshold determination and isothermal titration calorimetry. The millet huangjiu polysaccharide HJ-1 was composed of →3)-α-Manp(1→, α-Manp-(1→, →2,6)-α-Manp-(1→, →3)-α-Xylp-(1→ and →3)-β-Arap-(1→. HJ-1 (0.1–1 mg/mL) could regulate the release performance of key flavor compounds in millet huangjiu, inhibit the herbal, fruity and alcoholic aromas, and promote the sweet and rice aromas. Further studies showed that HJ-1 formed complexes with ethyl acetate, acetic acid, 2,3-butanediol and γ-butyrolactone through van der Waals forces and hydrogen bonds, and the process was a spontaneous exothermic entropy reduction reaction. This study provides a new idea for optimizing the overall aroma of huangjiu and improving its sensory quality.

WDR5 Binding to Histone Serotonylation Is Driven by an Edge-Face Aromatic Interaction with Unexpected Electrostatic Effects.

Histone serotonylation has emerged as a key post-translational modification. WDR5 preferentially binds to serotonylated histone 3 (H3), and this binding event has been associated with tumorigenesis. Herein, we utilize genetic code expansion, structure-activity relationship studies, and computation to study an edge-face aromatic interaction between WDR5 Phe149 and serotonin on H3 that is key to this protein-protein interaction. We find experimentally that this edge-face aromatic interaction is unaffected by modulating the electrostatics of the face component but is weakened by electron-withdrawing substituents on the edge component. Overall, these results elucidate that this interaction is governed by van der Waals forces as well as electrostatics of the edge ring, a result that clarifies discrepancies among previous theoretical models and model system studies of this interaction type. This is the first evaluation of the driving force of an edge-face aromatic interaction at a protein-protein interface and provides a key benchmark for the nature of these understudied interactions that are abundant in the proteome.

A Highly Sensitive, Low Creep Hydrogel Sensor for Plant Growth Monitoring

Ion−conducting hydrogels show significant potential in plant growth monitoring. Nevertheless, traditional ionic hydrogel sensors experience substantial internal creep and inadequate sensitivity, hindering precise plant growth monitoring. In this study, we developed a flexible hydrogel sensor composed of polyvinyl alcohol and acrylamide. The hydrogel sensor exhibits low creep and high sensitivity. Polyvinyl alcohol, acrylamide, and glycerol are crosslinked to create a robust interpenetrating double network structure. The strong interactions, such as van der Waals forces, between the networks minimize hydrogel creep under external stress, reducing the drift ratio by 50% and the drift rate by more than 60%. Additionally, sodium chloride and AgNWs enrich the hydrogel with conductive ions and pathways, enhancing the sensor’s conductivity and demonstrating excellent response time (0.4 s) and recovery time (0.3 s). When used as a sensor for plant growth monitoring, the sensor exhibits sensitivity to small strains and stability for long−term monitoring. This sensor establishes a foundation for developing plant health monitoring systems utilizing renewable biomass materials.

Effects of L-Proline on the Stability of Mulberry Anthocyanins and the Mechanism of Interaction between L-Proline and Cyanidin-3-O-Glycoside.

The protective effects of L-aspartic acid, L-valine, and L-proline on the stability of mulberry anthocyanins were investigated. Results showed that L-aspartic acid, L-valine, and L-proline significantly enhanced (p < 0.05) the stability of mulberry anthocyanins under constant light or ascorbic acid (AA). L-Proline had the best protective effect against anthocyanin degradation. The interaction between L-proline and cyanidin-3-O-glucoside (C3G) through hydrogen bonding and van der Waals forces, which improved the stability of C3G, was confirmed using FT-IR, 1H NMR, XRD, and molecular docking analyses, as well as molecular dynamics modes. In vitro digestion experiments yielded that both 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging capacities of the C3G/Pro group were increased in the intestinal fluid (p < 0.05). The above findings suggest that L-proline effectively slowed down the degradation of mulberry anthocyanins, and that it could be used as an auxiliary pigment and food additive to extend the optimal flavor period of products containing mulberry anthocyanins, and can improve the bioavailability of mulberry anthocyanins.

A comprehensive investigation of the nano-[Cu2-(DIP)2-EA] effects on HSA through spectroscopic procedures and computer simulations

In this research, the toxicity of nano-[Cu2-(DIP)2-EA], a metal nano-complex consisting of ellagic acid and bathophenanthroline ligands, on human serum albumin (HSA) at a protein level was investigated. Molecular docking simulations and spectral analyses were conducted in a simulated physiological environment at pH 7.4 to explore the interaction of nano-[Cu2-(DIP)2-EA] with HSA. The results represented an increase in albumin absorption upon exposure to nano-[Cu2-(DIP)2-EA], demonstrating significant interaction between the two compounds. Steady-state and time-resolved fluorescence measurements pointed out that nano-[Cu2-(DIP)2-EA] induced static quenching of the albumin's intrinsic fluorescence with a high binding affinity of approximately 106 mol/L in a 1:1 interaction ratio. The thermodynamic variables clarified that binding of nano-[Cu2-(DIP)2-EA] to albumin occurs spontaneously and primarily driven by van der Waals interactions and H-bonds. The results of the computer simulations and the binding displacement experiments utilizing the site markers warfarin and ibuprofen revealed that nano-[Cu2-(DIP)2-EA] binds to site I within the subdomain IIA of albumin. Circular dichroism analysis elaborated that nano-[Cu2-(DIP)2-EA] slightly perturbed the microenvironment around of tryptophan residues and diminished the α-helix structure stability to a negligible amount.

Investigation of interaction mechanism between polyvinyl chloride microplastics and phthalate acid esters using APGC-MS/MS

Phthalate acid esters (PAEs) are a kind of typical endocrine disruptors chemicals (EDCs). PAEs can be enriched, migrated and released into organisms through microplastics (MPs), causing high toxicological risks. This study presented an atmospheric pressure gas chromatography-tandem mass spectrometry (APGC-MS/MS) method for 10 PAEs trace analysis. Based on this method, the interaction mechanism between polyvinyl chloride microplastics (PVC MPs) and PAEs was explored. The established APGC-MS/MS method achieved 10 PAEs analysis in 14 min with the satisfied detection limit as low as 0.0025 μg/L and excellent linearity (R2 = 0.99868–0.99996). The interaction mechanism investigation showed that PVC MPs had high adsorption and desorption capacities for PAEs. The adsorption mechanism involves adsorption distribution, surface adsorption, hydrophobic interaction and intermolecular van der Waals force. Temperature, diffusion channels, pore filling, hydrophobicity and solubilization may be potential desorption mechanisms. Moreover, the intestinal environment of warm-blood organisms has the highest bioavailability of PAEs. Overall, this APGC-MS/MS method of PAEs had the virtue of simplicity, efficiency, reliability and sensitivity, and could serve as a potential tool for risk analysis of MPs and PAEs exposure.

Synthesis, non-spherical structure refinement and Hirshfeld surface analysis of racemic 2,2'-diisobut-oxy-1,1'-bi-naphthalene.

In the racemic title compound, C28H30O2, the naphthyl ring systems subtend a dihedral angle of 68.59 (1)° and the mol-ecular conformation is consolidated by a pair of intra-molecular C-H⋯π contacts. The crystal packing features a weak C-H⋯π contact and van der Waals forces. A Hirshfeld surface analysis of the crystal structure reveals that the most significant contributions are from H⋯H (73.2%) and C⋯H/H⋯C (21.2%) contacts.

Theoretical investigation of potential energetic material CL-20/TNBP co-crystal explosive based on molecular dynamics method.

The exploration of CL-20 eutectic has been a subject of fervent interest within the realm of high-energy material modification. Through the utilization of density functional and molecular dynamics methods, an investigation into the characteristics of hexanitrohexaazaisowurtzitane (CL-20)/4,4',5,5'-tetranitro-2H,2'H-3,3'-bipyrazole (TNBP)within the molar ratio range of 4:1-1:4 was conducted. This inquiry encompassed the scrutiny of molecular interaction pathways, attachment force, initiating molecular distance, unified energy concentration, and physical characteristics. Furthermore, the EXPLO-5 was harnessed to prognosticate the explosion features and byproducts of unadulterated CL-20, TNBP, and CL-20/TNBP frameworks. The findings delineate a substantial differentiation in the electrostatic charge distribution on the surface between CL-20 and TNBP particles, signifying the preeminence of intermolecular interactions between disparate entities over those within similar entities, thus intimating the plausibility of the eutectic constitution. Remarkably, the identification of maximal attachment force at a molar ratio of 1:1 suggests the heightened likelihood of eutectic formation, propelled primarily by electrostatic and van der Waals forces. The resultant eutectic explosive evinces intermediate reactivity and exemplary mechanical attributes. Moreover, the detonation achievement of the eutectic with a molar proportion of 1:1 straddles that of CL-20 and TNBP, representing a new type of insensitive high-energy material. The testing method employs the Materials Studio software and utilizes the molecular dynamics (MD) method to predict the properties of CL-20/TNBP cocrystals with different ratios and crystal faces. The MD simulation time step is set to 1fs, and the total MD simulation time is 2ns. An isothermal-isobaric (NPT) ensemble is used for the 2ns MD simulation. The COMPASS force field is employed, with the temperature set to 295K. The prediction of detonation characteristics and products is conducted using the EXPLO-5 software.

Experimental and Theoretical Studies on the Adsorption of Bromocresol Green from Aqueous Solution Using Cucumber Straw Biochar

Biochar prepared from crop straw is an economical method for adsorbing bromocresol green (BCG) from textile industrial wastewater. However, there is limited research on the adsorption mechanism of biochar for the removal of BCG. This study utilized cucumber straw as raw material to prepare biochar with good adsorption potential and characterized its physicochemical properties. Through adsorption experiments, the effects of solution pH, biochar dosage, and initial dye concentration on adsorption performance were examined. The adsorption mechanism of cucumber straw biochar (CBC) for BCG was elucidated at the molecular level using adsorption kinetics, adsorption isotherm models, and density functional theory (DFT) calculations. Results show that the specific surface area of the CBC is 101.58 m2/g, and it has a high degree of carbonization, similar to the structure of graphite crystals. The presence of aromatic rings, –OH groups, and –COOH groups in CBC provides abundant adsorption sites for BCG. The adsorption process of CBC for BCG is influenced by both physical and chemical adsorption, and can be described by the Langmuir isotherm model, indicating a monolayer adsorption process. The theoretical maximum monolayer adsorption capacity (qm) of BCG at 298 K was calculated to be 99.18 mg/g. DFT calculations reveal interactions between BCG and CBC involving electrostatic interactions, van der Waals forces, halogen–π interactions, π–π interactions, and hydrogen bonds. Additionally, the interaction of hydrogen bonds between BCG and the –COOH group of biochar is stronger than that between BCG and the –OH group. These findings provide valuable insights into the preparation and application of efficient organic dye adsorbents.

Adsorption ability of sugar scum as industrial waste for crystal violet elimination: Experimental and advanced statistical physics modeling

Recycling solid industrial waste into useful resources is the most critical aspect of managing waste. Herein, for detoxifying poisonous crystal violet dye (CV) in aqueous media, sugar scum (SS) as an underutilized industrial discard has been tested as a promising adsorbent.The SS was thoroughly analyzed beforehand and after the adsorption process through various characterization techniques. Several operational factors, including pH, biosorbent dosage, dye concentration, and temperature, were optimized, reaching 24 mg.g-1 at (pH 10, 2 g.L−1 of SS, 10 mg.L−1 of CV and 25 °C). The bioadsorbent's performance was assessed through a range of studies involving kinetic, equilibrium (using both conventional and statistical physics models), and thermodynamic investigations.Based on the results, the equilibrium curves best fit the Freundlich model, indicating that multilayer adsorption occurs on a heterogeneous active sites surface. The statistical physics models provided detailed physiochemical insights, the double-layer with two energies model was most accurately describing the data, with a high saturation capability of 371 mg.g−1. Most interactions occur at a single adsorption site (70 %), with the remaining 30 % at two sites, involving both parallel and non-parallel orientations. The mesoporous structure of the SS surface provides an optimum size for CV adsorption. Pore filling, Van der Waals forces, hydrogen bonding, π-π and electrostatic interactions are proposed as the possible mechanisms in the CV-SS system. Thermodynamic measurements indicate that CV adsorption is spontaneous (ΔG° < 0) and exothermic ΔH° (− 41.390 kJ mol−1).The SS recyclability was assessed, exhibiting encouraging sustainability with a slight fall in effectiveness (∼7 %) after 5 sequential usages. Altogether, this study makes a substantial contribution to the promotion of ecological water treatment strategies, which highlights the utility of using SS as an environmental alternative to water contaminant remediation.

Comprehensive analysis of lignin dimer dissolution microscopic mechanism in different aromatic-based deep eutectic solvent

Aromatic-based deep eutectic solvent (DES) is a novel kind of DES that can dissolve lignin efficiently. Density functional (DFT) calculation, molecular dynamics (MD) simulation and multivariate analysis were used to investigate the interaction mechanism of five aromatic-based DES on two lignin dimer models. The effects of dissolution temperature and the type of aromatic hydrogen bond donor (HBD) on the breaking bonds between β-O-4 and 5–5 substructural units or interacting with different functional groups on lignin were investigated. With the introduction of DES, the electrostatic interaction between Cl- and lignin was obvious, while the van der Waals interaction between HBD, Ch+ and lignin was obvious. Among all the aromatic-based DES, choline chloride/p-hydroxybenzoic acid (ChCl/PB) is considered to have efficient dissolution effect. In the process of lignin dissolution, γ-OH was the preferred site for PB and Cl- acting on the lignin dimer (β-O-4), and the proportion of hydrogen bonding with γ-OH is 40 %. It was distributed around the lignin dimer (β-O-4) at 0.28–0.32 nm, and the total interaction energy was −4041.1452 kJ/mol. This study provided novel insights and theoretical basis for the preparation of renewable DES using aromatic components.

Tunable Interlayer Interactions in Exfoliated 2D van der Waals Framework Fe(SCN)2(Pyrazine)2.

2D materials can be isolated as monolayer sheets when interlayer interactions involve weak van der Waals forces. These atomically thin structures enable novel topological physics and open chemical questions of how to tune the structure and properties of the sheets while maintaining them as isolated monolayers. Here, this work investigates 2D electroactive sheets that exfoliate in solution into colloidal nanosheets, but aggregate upon oxidation, giving rise to tunable interlayer charge transfer absorption and photoluminescence. This optical behavior resembles interlayer excitons, now intensely studied due to their long-lived emission, but which remain difficult to tune through synthetic chemistry. Instead, the interlayer excitons of these framework sheets can be modulated through control of solvent, electrolyte, oxidation state, and the composition of the framework building blocks. Compared to other 2D materials, these framework sheets display the largest known interlayer binding strengths, attributable to specific orbital interactions between the sheets, and among the longest interlayer exciton lifetimes. Taken together, this study provides a microscopic basis for manipulating long-range opto-electronic behavior in van der Waals materials through molecular synthetic chemistry.

Boron-Doped Single-Molecule van der Waals Diode.

Single-molecule diode was the first proposed device in molecular electronics. Despite the great efforts and advances over 50 years, the reported rectification ratios, the most critical parameter of a diode, remain moderate for the single-molecule diode. Herein, we report an approach to achieve a larger rectification ratio by adopting the combined strategies of p-type boron doping, the single-layer graphene nodes, and the van der Waals layer-by-layer architecture. Measured current-voltage curves showed one of the as-fabricated single-molecule diodes hit an unprecedented large rectification ratio of 457 at ±1 V. Break junction operations and spectroscopic measurements revealed the three-atom-thick configuration of the single-molecule diodes. With the experimental and theoretical calculation results, we demonstrated the doped boron atoms induced holes to redistribute the electron density, making the asymmetric coupling at positive and negative biases, and the van der Waals interaction promoted asymmetric coupling and significantly boosted diode performance.