Probing impact on magnetic behavior of cobalt layer grown on thick MoS 2 layer.

Understanding the metal-semiconductor heterostructure interface is crucial for the development of spintronic devices. One of the prospective candidates and extensively studied semiconductors is molybdenum disulfide (MoS 2 ). Herein, utilizing Kerr microscopy, we investigated the impact of thick MoS 2 on the magnetic properties of the 10 nm Co layer. A comparative study on Co / MoS 2 and Co/Si shows that coercivity increased by 77% and the Kerr signal decreased by 26% compared to Co grown on Si substrate. In addition, the Co domain structure significantly changed when grown on MoS 2 . The plausible reason for the observed magnetic behavior can be that the Co interacts differently at the interface of MoS 2 as compared to Si. Therefore, our studies investigate the interfacial effect on the magnetic properties of Co grown on thick MoS 2 layer. Furthermore, our results will help in developing next-generation spintronic devices.

Pioneering method for the synthesis of lead sulfide (PbS) nanoparticles using a surfactant-free microemulsion scheme.

In this study, we report the synthesis of PbS particles having dimensions in the quantum-dot regime (13.17 to 26.91 nm) using a cyclohexane:isopropanol:dimethyl-sulfoxide surfactant-free microemulsion (CID-SFME) scheme without a capping agent. We found that with an increase in the microemulsion concentration and particle size, there was a simultaneous reduction in band gap due to the quantum confinement effect. Furthermore, a microemulsion concentration of 0.0125 M was the optimum microemulsion concentration for the growth of uniformly distributed, small particle-sized, ordered PbS nanoparticles using CID-SFME at a constant temperature and other effective parameters. From the results obtained in the present study, we believe that during the reaction, it was not the low values of viscosity and dielectric constant that were responsible for keeping PbS stabilized inside the core of the micelle of the CID microemulsion, but rather the van der Waals forces that also controlled the growth of spherical PbS. We fabricated a highly stable FTO/TiO2/PbS/PANI/NiS/C photodetector at an optimized microemulsion solution concentration. The fabricated photodetector showed a rise time of ∼0.39 s and a decay time of ∼0.22 s, with a photoresponsivity of ∼5.466 µA W-1, external quantum efficiency of ∼0.116 × 10-4%, and detectivity of 6.83 × 107 Jones. Therefore, the CID-SFME scheme is an easy, low-cost route to fabricate efficient, precise, stable, and fast-switching photodetector devices.

Modification in Toxicity of l-Histidine-Incorporated ZnO Nanoparticles toward Escherichia coli.

This paper presents a comparative study of the toxicity of pristine-ZnO and l-histidine-incorporated ZnO toward Escherichia coli (E. coli) as a Gram-negative model organism. Pristine-ZnO and l-histidine-incorporated ZnO with different l-histidine concentrations were synthesized using an open aqueous solution bath technique. XRD studies revealed the formation of polycrystalline wurtzite ZnO. The average crystallite size of the synthesized l-histidine-incorporated ZnO decreased as the concentration of l-histidine increased. The FTIR spectra showed the presence of Zn-O, CO2-/CO3-, and C-N (only in l-histidine-incorporated ZnO samples) and -OH bond vibration signals in all samples. The chemical purity of all the samples was ensured using XPS analysis. The microbial activity of these samples was investigated using E. coli. The solution with 100 µg/mL ZnO in sterile distilled water showed up to 94% growth inhibition of E. coli, establishing antibacterial activity. However, l-histidine incorporated in ZnO showed reduced antibacterial activity with the increase of the concentration of l-histidine in ZnO. Furthermore, flow cytometry studies during the interaction of ZnO and E. coli confirmed the generation of reactive oxygen species (ROS), validating its antibacterial activity. The interaction of l-histidine-incorporated ZnO and E. coli showed declining ROS with the increase in the l-histidine concentration, indicating a ZnO toxicity reduction.

Removal of crystal violet dye using a three-dimensional network of date pits powder/sodium alginate hydrogel beads: Experimental optimization and DFT calculation.

Biodegradable and very low-cost adsorbent beads were prepared from date pits powder (DP) and sodium alginate (SA). DP to SA ratios was varied (1/2, 1/4 and 1/6) and used to eliminate Crystal violet (CV) a cationic dye. Adsorbents were characterized by FTIR, SEM-EDS, UV-vis DR, TGA and the point of zero charge (pHPZC). The optimal composite beads SA@6DP show high adsorption capacities of 83.565 mg/g toward CV than SA@2DP and SA@4DP. The kinetics investigation showed that the adsorption is well described by the pseudo-second-order kinetic (R2 = 0.998). The thermodynamics and isotherms studies exhibit that the adsorption phenomenon for SA@6DP adsorbent is endothermic and significantly fitted with the Redlich-Peterson model. The experimental adsorption tests were optimized by the Box-Behnken design (BBD) which led to conclude the maximal CV removal efficiency achieved by SA@6DP was 99.873 % using [CV] = 50 mg/L, adsorbent mass = 20 mg and 48 h of contact time. The theoretical calculation proved that the CV molecules favor the mode of attack due to their electrophilic character and can accept the SA@6DP adsorbent electrons more easily to form an anti-bonding orbital. SA@6DP hydrogel beads are therefore an exceptional bio-adsorbent that offers excellent adsorption performance.

ß-Cyclodextrin-Functionalized Fe3O4-Supported Pd-Nanocatalyst for the Reduction of Nitroarenes in Water at Mild Conditions.

In this study, a novel heterogeneous catalyst (Fe3O4@ß-CD@Pd) has been developed by the deposition of palladium nanoparticles on the ß-cyclodextrin-functionalized surface of magnetic Fe3O4. The catalyst was prepared by a simple chemical co-precipitation method and characterized extensively by using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-optical emission spectrometry (ICP-OES) analyses. Herein, the applicability of the prepared material was evaluated for the catalytic reduction of environmentally toxic nitroarenes to the corresponding anilines. The catalyst Fe3O4@ß-CD@Pd showed excellent efficiency for the reduction of nitroarenes in water under mild conditions. A low catalyst loading of 0.3 mol % Pd is found to be efficient for reducing nitroarenes in excellent to good (99-95%) yields along with high TON values (up to 330). Nevertheless, the catalyst was recycled and reused up to the 5th cycle of reduction of nitroarene without any loss of significant catalytic activity.

Enhanced photoresponse of Cu2ZnSnS4 absorber thin films fabricated using multi-metallic stacked nanolayers.

Cu2ZnSnS4 (CZTS) thin films have attracted considerable attention as potential candidates for photovoltaic absorber materials. In a vacuum deposition technique, a sputtering stacked metallic layer followed by a thermal process for sulfur incorporation is used to obtain high-quality CZTS thin films. In this work, for fabricating CZTS thin films, we have done a 3LYS (3 layers), 6LYS, and 9LYS sequential deposition of Sn/ZnS/Cu metal stack (via. metallic stacked nanolayer precursors) onto Mo-coated corning glass substrate via. RF-sputtering. The prepared thin films were sulfurized in a tubular furnace at 550 °C in a gas mixture of 5% H2S + 95% Ar for 10 min. We further investigated the impact of the Sn/ZnS/Cu metal stacking layers on the quality of the thin film based on its response to light because metal inter-diffusion during sulfurization is unavoidable. The inter-diffusion of precursors is low in a 3-layer stack sample, limiting the fabricated film's performance. CZTS films with 6-layer and 9-layer stacks result in an improved photocurrent density of ∼38 µA cm-2 and ∼82 µA cm-2, respectively, compared to a 3-layer sample which has a photocurrent density of ∼19 µA cm-2. This enhancement can be attributed to the 9-layer approach's superior inter-diffusion of metallic precursors and compact, smooth CZTS microstructure evolution.

Comparative Studies on Synthesis, Characterization and Photocatalytic Activity of Ag Doped ZnO Nanoparticles.

In this work, silver (Ag) doped zinc oxide (ZnO) nanoparticles were synthesized using zinc chloride, zinc nitrate, and zinc acetate precursors with (0 to 10) wt % Ag doping by a simple reflux chemical method. The nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet visible spectroscopy, and photoluminescence spectroscopy. The nanoparticles are studied as a photocatalyst for visible light driven annihilation of methylene blue and rose bengal dyes. The 5 wt % Ag doped ZnO displayed optimum photocatalytic activity toward methylene blue and rose bengal dye degradation at the rate of 13 × 10-2 min-1 and 10 × 10-2 min-1, respectively. Here we report antifungal activity for the first time using Ag doped ZnO nanoparticles against Bipolaris sorokiniana, displaying 45% efficiency for 7 wt % Ag doped ZnO.

Modified Whale Optimization Algorithm based ANN: a novel predictive model for RO desalination plant.

In recent decades, nature-inspired optimization methods have played a critical role in helping industrial plant designers to find superior solutions for process parameters. According to the literature, such methods are simple, quick, and indispensable for saving time, money, and energy. In this regard, the Modified Whale Optimization Algorithm (MWOA) hybridized with Artificial Neural Networks (ANN) has been employed in the Reverse Osmosis (RO) desalination plant performance to estimate the permeate flux (0.118‒2.656 L/h m2). The plant's datasets have been collected from the literature and include four input parameters: feed flow rate (400‒600 L/h), evaporator inlet temperature (60‒80 °C), feed salt concentration (35‒140 g/L) and condenser inlet temperature (20‒30 °C). For this purpose, ten predictive models (MWOA-ANN Model-1 to Model-10) have been proposed, which are capable of predicting more accurate permeate flux (L/h m2) than the existing models (Response Surface Methodology (RSM), ANN and hybrid WOA-ANN models) with minimum errors. Simulation results suggest that the MWOA algorithm demonstrates a stronger optimization capability of finding the correct weights and biases so as to enable superior ANN based modeling without limitation of overfitting. Ten MWOA-ANN models (Model-1 to Model-10) have been proposed to investigate the plant's performance. Model-6 with a single hidden layer (H = 1), eleven hidden layer nodes (n = 11) and the thirteen search agents (SA = 13) produced most outstanding regression results (R2 = 99.1%) with minimal errors (MSE = 0.005). The residual errors for Model-6 are also found to be within limits (span of - 0.1 to 0.2). Finally, the findings show that the screened MWOA-ANN models are promising for identifying the best process parameters in order to assist industrial plant designers.

Self-biased photodetector using 2D layered bismuth triiodide (BiI3) prepared using the spin coating method.

Layered bismuth triiodide (BiI3) is a 2D material that has emerged as an ideal choice for optical sensors. Although BiI3 has been prepared using vacuum-based deposition techniques, there is a dearth of research studies on synthesizing this material using chemical route. The present work uses a facile spin coating method with varying rotation speeds (rpm) to fabricate BiI3 material thin films for photodetection applications. The structural, optical, and morphological study of BiI3 thin films prepared at 3000-6000 rpm were investigated. XRD analysis indicates formation of BiI3 films and revealed that BiI3 has a rhombohedral crystal structure. FESEM analysis showed that BiI3 films prepared at different rpm are homogeneous, dense, and free from cracks, flaws, and protrusions. In addition, films show an island-like morphology with grain boundaries having different grain sizes, micro gaps, and the evolution of the granular morphology of BiI3 particles. The UV spectroscopy and photoluminescence analysis revealed that BiI3 films strongly absorb light in the visible region of spectra with a high absorption coefficient of ∼104 cm-1, have an optical band gap of ∼1.51 eV. A photodetector was realised using fabricated BiI3 film obtained at an optimum spin speed of 4000 rpm. It showed rapid rise and decay times of 0.4 s and 0.5 s, a responsivity of ∼100 µA W-1, external quantum efficiency of 2.1 × 10-4%, and detectivity of ∼3.69 × 106 Jones at a bias voltage of 0 V. Our results point towards a new direction for layered 2D BiI3 materials for the application in self-biased photodetectors.

Synthesis, Structural and Optical Properties of ZrBi2Se6 Nanoflowers: A Next-Generation Semiconductor Alloy Material for Optoelectronic Applications.

ZrBi2Se6 nanoflower-like morphology was successfully prepared using a solvothermal method, followed by a quenching process for photoelectrochemical water splitting applications. The formation of ZrBi2Se6 was confirmed by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The estimated value of work function and band gap were found to be 5.5 and 2.26 eV measured using diffuse reflection spectroscopy and ultraviolet photoelectron spectroscopy, suggesting the potential candidate for water splitting. The highest current density of 9.7 µA/cm2 has been observed for the ZrBi2Se6 photoanode for the applied potential of 0.5 V vs SCE. The flat-band potential value was -0.46 V, and the 1.85 nm width of the depletion region is estimated from the Mott-Schottky (MS) analysis. It also reveals that the charge carrier density for the ZrBi2Se6 nanoflowers is 4.8 × 1015 cm-3. The negative slope of the MS plot indicates that ZrBi2Se6 is a p-type semiconductor. It was observed that ZrBi2Se6 nanoflowers had a high charge transfer resistance of ∼730 kΩ and equivalent capacitance of ∼40 nF calculated using electrochemical impedance spectroscopy (EIS) measurements. Using chronoamperometry, the estimated rise time and decay time were 50 ms and 0.25 s, respectively, which reveals the fast photocurrent response and excellent PEC performance of the ZrBi2Se6 photoanode. Furthermore, an attempt has been made to explain the PEC activity of ZrBi2Se6 nanoflowers using an energy band diagram. Thus, the initial results on ZrBi2Se6 nanoflowers appear promising for the PEC activity toward water splitting.

Encapsulation Capacity of ß-Cyclodextrin Stabilized Silver Nanoparticles towards Creatinine Enhances the Colorimetric Sensing of Hydrogen Peroxide in Urine.

The ß-cyclodextrin shell of synthesized silver nanoparticles (ßCD-AgNPs) are found to enhance the detection of hydrogen peroxide in urine when compared to the Horse Radish Peroxidase assay kit. Nanoparticles are confirmed by the UV-Vis absorbance of their localized surface plasmonic resonance (LSPR) at 384 nm. The mean size of the ßCD-AgNPs is 53 nm/diameter; XRD analysis shows a face-centered cubic structure. The crystalline structure of type 4H hexagonal nature of the AgNPs with 2.4 nm ß-CD coating onto is confirmed using aberration corrected high-resolution transmission electron microscopy (HRTEM). A silver atomic lattice at 2.50 Å and 2.41 Å corresponding to (100) and (101) Miller indices is confirmed using the HRTEM. The scope of ßCD-AgNPs to detect hydrogen peroxide (H2O2) in aqueous media and human urine is investigated. The test is optimized by examining the effect of volumes of nanoparticles, the pH of the medium, and the kinetic and temperature effect on H2O2 detection. The ßCD-AgNPs test is used as a refined protocol, which demonstrated improved sensitivity towards H2O2 in urine compared to the values obtained by the Horse Radish Assay kit. Direct assessment of H2O2 by the ßCD-AgNPs test presented always with a linear response in the nM, µM, and mM ranges with a limit of detection of 1.47 nM and a quantitation limit of 3.76 nM. While a linear response obtained from 1.3 to 37.3 nmoles of H2O2/mole creatinine with a slope of 0.0075 and regression coefficient of 0.9955 when the ßCD-AgNPs is used as refined test of creatinine. Values ranging from 34.62 ± 0.23 nmoles of H2O2/mole of creatinine and 54.61 ± 1.04 nmoles of H2O2/mole of creatinine when the matrix is not diluted and between 32.16 ± 0.42 nmoles of H2O2/mole of creatinine and 49.66 ± 0.80 nmoles of H2O2/mole of creatinine when the matrix is twice diluted are found in freshly voided urine of seven apparent healthy men aged between 20 and 40 years old.

Phonon Dynamics and Transport Properties of Copper Thiocyanate and Copper Selenocyanate Pseudohalides.

The phonon transport properties of CuSCN and CuSeCN have been investigated using the density functional theory and semiclassical Boltzmann transport theory. The Perdew-Burke-Ernzerhof functional shows an indirect (direct) electronic band gap of 2.18 eV (1.80 eV) for CuSCN (CuSeCN). The calculated phonon band structure shows that both compounds are dynamically stable. The Debye temperature of the acoustic phonons is 122 and 107 K for CuSCN and CuSeCN, respectively. The extended in-plane bond lengths as compared to the out-of-plane bond lengths result in phonon softening and hence, low lattice thermal conductivity. The calculated room temperature in-plane (out-of-plane) lattice thermal conductivity of CuSCN and CuSeCN is 2.39 W/mK (4.51 W/mK) and 1.70 W/mK (3.83 W/mK), respectively. The high phonon scattering rates in CuSeCN give rise to in-plane low lattice thermal conductivities. The room-temperature Grüneisen parameters of CuSCN and CuSeCN are found to be 0.98 and 1.08, respectively.

Green Synthesis, Characterization, Antimicrobial, Anti-Cancer, and Optimization of Colorimetric Sensing of Hydrogen Peroxide of Algae Extract Capped Silver Nanoparticles.

A green and cost-effective technique for the preparation of silver nanoparticles (Algae-AgNPs) as a colorimetric sensor for hydrogen peroxide (H2O2) is described. Silver nanoparticles were capped using the green algae (Noctiluca scintillans) extract at an optimum time of 3 h at 80 °C. The pH of the plant extract (pH = 7.0) yields nanoparticles with a mean size of 4.13 nm and a zeta potential of 0.200 ± 0.02 mV and negative polarity, using dynamic light scattering (DLS). High-resolution transmission electron microscopy (HRTEM) analysis showed regular spherical particles with the average size of 4.5 nm. Selected area electron diffraction (SAED) results revealed the polycrystalline nature of the silver nanoparticles. The obtained patterns were indexed as (111), (200), (220), and (311) reflections of the fcc (face centered cubic) silver crystal based on their d-spacing of 2.47, 2.13, 1.49, and 1.27 Å, respectively. The apparent color change from brown to colorless was observed when nanoparticles reacted with H2O2. Linear responses were obtained in three different ranges (nM, µM, and mM). Limits of detection (LOD) of 1.33 ± 0.02 and 1.77 ± 0.02 nM and quantitation limits (LOQ) of 7.31 ± 0.03 and 9.67 ± 0.03 nM were obtained for Abs and ΔAbs calibration curves, respectively. 10% v/v Algae-AgNPs solution inhibited Staphylococcus aureus over Escherichia coli, while a 50% reduction of tumor cell growth of MDA-MB-231 human breast adenocarcinoma was obtained.

Tensile behaviors of Ti3C2Tx (MXene) films.

As the most representative member of a new emerging family of 2D material, titanium carbides or nitrides (MXenes), Ti3C2Tx and its 2D assembly format, Ti3C2Tx film, have displayed outstanding performance in a broad range of practical applications. However the mechanical behaviors of Ti3C2Tx films are rarely reported. We report a systematic study of the tensile behavior of Ti3C2Tx films. Ti3C2Tx films with various thicknesses (2-17 µm) were prepared by the vacuum filtration method. Quasi-static tension and cyclic tension tests were performed to investigate the deformation and fracture mechanism of Ti3C2Tx films. It was found that: (1) the relative sliding between Ti3C2Tx flakes is the dominant deformation mechanism of Ti3C2Tx films. Cyclic loading-releasing in tension suppresses the inter-layer sliding of Ti3C2Tx flakes effectively and thus the tensile strength of thicker Ti3C2Tx film (5 µm) film improves from 57 MPa to 67 MPa. (2) The mechanical properties of Ti3C2Tx films are found to be thickness dependent. When the film thickness increases from 2.3 to 17 µm, the tensile strength and elastic modulus drop from 61 to 36 MPa and from 17 to 8 GPa, respectively. This is interpreted as more structural defects presented in the through-the-thickness direction as film thickness is increased. (3) Moderate ultrasonication pretreatment (30 min) reduces the Ti3C2Tx flake size significantly while improving the compactness of the Ti3C2Tx film; and the resulting Ti3C2Tx film shows a linear stress-strain relationship without plastic-like deformation. As a result, the tensile strength of 5 µm thick Ti3C2Tx film is enhanced to 85 MPa; (4) Structural defects of the Ti3C2Tx film have significant effects on both the brittle-like fracture behavior and the distribution of tensile strength.

A wet-filtration-zipping approach for fabricating highly electroconductive and auxetic graphene/carbon nanotube hybrid buckypaper.

A combination of carbon nanotubes (CNT) and graphene in the form of macroscopic hybrid buckypaper (HBP), exhibits a unique set of properties that can be exploited for many emerging applications. Here, we present a simple, inexpensive and scalable approach for the synthesis of highly conductive auxetic graphene/CNT HBP via wet-filtration-zipping and demonstrate the electrical, electrochemical and mechanical performance (tensile, mode I and mode III fracture) of synthesized HBP. An overall increase in electrical conductivity of 247% is observed for HBP (50 wt.% graphene and 50 wt.% CNT) as compared to BP (100 wt.% CNT) due to effective electronic percolation through the graphene and CNT. As a negative electrode for lithium-ion batteries, HBP shows 50% higher gravimetric specific capacity and 89% lower charge transfer resistance relative to BP. The graphene content in the HBP influences the mechanical performance providing an auxetic structure to HBP with large negative Poisson's ratio. The facile green-chemistry approach reported here can be readily applied to any other 1D and 2D materials and solves key challenges associated with existing buckypaper manufacturing methods. The potential of the synthesis method to integrate with current cellulose paper manufacturing technology and its scalability demonstrate the novelty of the work for industrial scale production.

Elemental Quantification and Residues Characterization of Wet Digested Certified and Commercial Carbon Materials.

Inductively coupled plasma optical emission spectroscopy (ICP-OES) is a common, relatively low cost, and straightforward analytical technique for the study of trace quantities of metals in solid materials, but its applicability to nanocarbons (e.g., graphene and nanotubes) has suffered from the lack of efficient digestion steps and certified reference materials (CRM). Here, various commercial and certified graphitic carbon materials were subjected to a "two-step" microwave-assisted acid digestion procedure, and the concentrations of up to 18 elements were analyzed by ICP-OES. With one exception (Sm), successful quantification of all certified elements in the two reference nanocarbons studied was achieved, hence validating the sample preparation approach used. The applicability of our "two-step" protocol was further confirmed for a commercial single-walled carbon nanotube sample. However, the digestion was markedly incomplete for all other commercial materials tested. Where possible, the digestion residues of the carbon materials analyzed (CRM included) were characterized to understand the structural changes that take place and how this may explain the challenge of disintegrating graphitic carbon. In this respect, it was found that solid state nuclear magnetic resonance holds considerable promise as a nonlocalized, easily interpretable, and reliable tool to access the efficient disintegration of these materials.

A process to enhance the specific surface area and capacitance of hydrothermally reduced graphene oxide.

The impact of post-synthesis processing in reduced graphene oxide materials for supercapacitor electrodes has been analyzed. A comparative study of vacuum, freeze and critical point drying was carried out for hydrothermally reduced graphene oxide demonstrating that the optimization of the specific surface area and preservation of the porous network are critical to maximize its supercapacitance performance. As described below, using a supercritical fluid as the drying medium, unprecedented values of the specific surface area (364 m2 g-1) and supercapacitance (441 F g-1) for this class of materials have been achieved.

An evaluation of microwave-assisted fusion and microwave-assisted acid digestion methods for determining elemental impurities in carbon nanostructures using inductively coupled plasma optical emission spectrometry.

It is common for as-prepared carbon nanotube (CNT) and graphene samples to contain remnants of the transition metals used to catalyze their growth; contamination may also leave other trace elemental impurities in the samples. Although a full quantification of impurities in as-prepared samples of carbon nanostructures is difficult, particularly when trace elements are intercalated or encapsulated within a protective layer of graphitic carbon, reliable information is essential for reasons such as quantifying the adulteration of physico-chemical properties of the materials and for evaluating environmental issues. Here, we introduce a microwave-based fusion method to degrade single- and double-walled CNTs and graphene nanoplatelets into a fusion flux thereby thoroughly leaching all metallic impurities. Subsequent dissolution of the fusion product in diluted hydrochloric and nitric acid allowed us to identify their trace elemental impurities using inductively coupled plasma optical emission spectrometry. Comparisons of the results from the proposed microwave-assisted fusion method against those of a more classical microwave-assisted acid digestion approach suggest complementarity between the two that ultimately could lead to a more reliable and less costly determination of trace elemental impurities in carbon nanostructured materials.

Structural changes of electron and ion beam-deposited contacts in annealed carbon-based electrical devices.

The use of electron and ion beam deposition to make devices containing discrete nanostructures as interconnectors is a well-known nanofabrication process. Classically, one-dimensional materials such as carbon nanotubes (CNTs) have been electrically characterized by resorting to these beam deposition methods. While much attention has been given to the interconnectors, less is known about the contacting electrodes (or leads). In particular, the structure and chemistry of the electrode-interconnector interface is a topic that deserves more attention, as it is critical to understand the device behavior. Here, the structure and chemistry of Pt electrodes, deposited either with electron or ion beams and contacted to a CNT, are analyzed before and after thermally annealing the device in a vacuum. Free-standing Pt nanorods, acting as beam-deposited electrode models, are also characterized pre- and post-annealing. Overall, the as-deposited leads contain a non-negligible amount of amorphous carbon that is consolidated, upon heating, as a partially graphitized outer shell enveloping a Pt core. This observation raises pertinent questions regarding the definition of electrode-nanostructure interfaces in electrical devices, in particular long-standing assumptions of metal-CNT contacts fabricated by direct beam deposition methods.

Large work function difference driven electron transfer from electrides to single-walled carbon nanotubes.

A difference in work function plays a key role in charge transfer between two materials. Inorganic electrides provide a unique opportunity for electron transfer since interstitial anionic electrons result in a very low work function of 2.4-2.6 eV. Here we investigated charge transfer between two different types of electrides, [Ca(2)N](+)·e(-) and [Ca(24)Al(28)O(64)](4+)·4e(-), and single-walled carbon nanotubes (SWNTs) with a work function of 4.73-5.05 eV. [Ca(2)N](+) · e(-) with open 2-dimensional electron layers was more effective in donating electrons to SWNTs than closed cage structured [Ca(24)Al(28)O(64)](4+) · 4e(-) due to the higher electron concentration (1.3 × 10(22) cm(-3)) and mobility (∼ 200 cm(2) V(-1) s(-1) at RT). A non-covalent conjugation enhanced near-infrared fluorescence of SWNTs as high as 52%. The field emission current density of electride-SWNT-silver paste dramatically increased by a factor of 46,000 (14.8 mA cm(-2)) at 2 V µm(-1) (3.5 wt% [Ca(2)N](+) · e(-)) with a turn-on voltage of 0.85 V µm(-1).