Size Of Nanocubes Research Articles

Tuning the size of PbSe nanocubes for solar-cell applications

The size of PbSe cubes was tuned from microsize to nanosize by glycine as a surfactant using a co-precipitation method. Four samples were synthesized that one was without surfactant and the others were synthesized by different surfactant concentrations. It was observed that the morphology of the sample with the free-surfactant condition was cubic morphology with a microsize feature with an average size of 2 μm. Additionally, adding the surfactant to the synthesis solution led to obtaining PbSe nanocubes with an average size of 35 nm. Electrochemical impedance spectroscopy (EIS) and I-V results of the PbSe nanocubes indicated lower resistance for the smallest sizes of PbSe nanocubes. Furthermore, PbSe nanocubes with the smallest sizes showed a higher absorption coefficient than the other samples did. The capability of the obtained micro and nano PbSe cubes as an absorbing layer in a solar-cell device was examined. The solar-cell measurement results revealed a higher figure of merit for the sample with the lowest size such as 6.9% of power conversion efficiency (PCE) and 75% of fill-factor (FF).

Morphology dependent activity of PbS nanostructures for electrochemical sensing of dopamine

The present study reports synthesis of lead sulfide nanostructures by a facile thermal decomposition approach. Morphology dependent electrochemical characteristics have been investigated using cyclic voltammetry. PbS dendrites exhibit higher redox peak current and smaller peak potential separation compared to PbS nanocubes. Enhanced redox current, reduced peak potential, well-defined and stable redox wave indicate high electrocatalytic activity of PbS nanostructures towards dopamine. The crystallite size of dendrites and nanocubes was found to be 18.9 nm and 50.8 nm. The surface area of electrodes increased multi-fold on modification with PbS nanostructures (9.7 mm2) compared to bare electrode (1.2 mm2).

Effect of Write Head Movement On Magnetic Spin Domain Reversal of Nanocube Co/Pd Alloy Material Using Micromagnetic Simulation

An analysis of the effect of the write head movement on the reversal time of the domain spin with magnetic Co/Pd on the magnetic recording layer has been carried out through micromagnetic simulation. The magnetic recording layer is modeled in the form of cubes (nanocubes) which consists of 5 domain spin. The write head, which is a transduser, moves along the domain spin to write data in the form of magnetic spins, which represent the bits on the magnetic recorder perpendicular. The results of this simulation are a profile of changes in the total magnetic field and reversal time of the domain spin when writing magnetic data for 6 nanoseconds. The calculation used in this study is an analytical calculation regarding the reversal time of the magnetic domain spin of the Co/Pd alloy material. The formulation for calculating the reversal time of domain-spin magnetization is a combination of graphical analysis and analytical calculations with visualization of the magnetic spin configuration that consisting of 5 domains spin. This simulation was carried out using the finite element method and obtained a saturation 5 field value of the magnetic alloy Co/Pd (Hs) material of 2.5 x 105 A/m and a write head (Hwh) field that 6 must be applied to the magnetic recording layer in order to reverse the uniform domain spin is 7.3 x 106 A/m. Each size of the domain spin requires a different write head, the smaller the nanocube size, the greater the write head field applied to the magnetic recording layer. Meanwhile, the effective write head 6 field amplitude that is suitable for the 20 nm domain spin is 8.3 x 106 A/m. A significant change in the total field occurs when the domain spin reverses 3 times in the first domain spin (n1), the third domain spin (n3) and the fifth domain spin (n5). The total field value when t=0.42 ns ( first domain spin reversal) is 73.69376 A/m, then the total field at t=0.42 ns (third domain spin reversal) is 3443.197 A/m and the current total field t=0.42 ns (fifth domain spin reversal) of 5480.696 A/m.

Interface-induced controllable synthesis of Cu2O nanocubes for electroreduction CO2 to C2H4

Electroreduction CO2 to high value-added chemicals is a promising way to mitigate the greenhouse effect while storing the renewable electricity in chemicals. As an important chemical, C2H4 is a desirable product of CO2 reduction but limited by lacking of efficient and durable catalysts. Herein, we proposed an interface-induced method to prepare Cu2O nanocubes with controllable morphology and size. Due to the imidazolyl groups connected to the surface of ionic liquid functionalized graphite sheets (ILGS), Cu2O nanocubes were induced to grow on ILGS to obtain Cu2O/ILGS composites, where the size of Cu2O can be controlled by adjusting the concentration of Cu2+. Interestingly, as the concentration of Cu2+ increases from 12.5 mmol/L to 100 mmol/L, the size of Cu2O nanocubes decreases from 456 nm to 72 nm. As catalyst for CO2 electroreduction in 0.1 M KHCO3 aqueous solution, Cu2O/ILGS-100 (synthesized under 100 mmol/L CuCl2) behaves the best catalysis performance with a high faradic efficiency of C2H4 (31.1%) and long durability at −1.15 V (vs. reversible hydrogen electrode).

Ppb level triethylamine detection of yolk-shell SnO2/Au/Fe2O3 nanoboxes at low-temperature

Yolk-shell nanostructures with high specific surface area and more active areas become the development direction of gas sensors. In this work, yolk-shell SnO2/Au/Fe2O3 nanoboxes with specific surface area of 38.3 m2 g−1 were successfully prepared. The size of Fe2O3 nanocubes was about 300 nm, the thickness of SnO2 was about 20 nm and the diameter of Au nanoparticles was about 12 nm. Benefiting from the distinctive structure and catalytic activity of precious metals, the as-prepared SnO2/Au/Fe2O3 yolk-shell nanostructures showed outstanding response to triethylamine (TEA) gas at 240 °C. The response value to 100 ppm TEA gas was 126.84, which was about 6 times and 14 times of the Au/Fe2O3 and Fe2O3 samples. In addition, yolk-shell SnO2/Au/Fe2O3 nanoboxes also exhibited a low detection limit (50 ppb), good response and recovery character (7/10 s). This experiment provided novel ideas for the design of new nanostructures for gas sensors.

Orientational phase behavior of polymer-grafted nanocubes.

Surface functionalization of nanoparticles with polymer grafts was recently shown to be a viable strategy for controlling the relative orientation of shaped nanoparticles in their higher-order assemblies. In this study, we investigated in silico the orientational phase behavior of coplanar polymer-grafted nanocubes confined in a thin film. We first used Monte Carlo simulations to compute the two-particle interaction free-energy landscape of the nanocubes and identify their globally stable configurations. The nanocubes were found to exhibit four stable phases: those with edge-edge and face-face orientations, and those exhibiting partially overlapped slanted and parallel faces previously assumed to be metastable. Moreover, the edge-edge configuration originally thought to involve kissing edges instead displayed partly overlapping edges, where the extent of the overlap depends on the attachment positions of the grafts. We next formulated analytical scaling expressions for the free energies of the identified configurations, which were used for constructing a comprehensive phase diagram of nanocube orientation in a multidimensional parameter space comprising of the size and interaction strength of the nanocubes and the Kuhn length and surface density of the grafts. The morphology of the phase diagram was shown to arise from an interplay between polymer- and surface-mediated interactions, especially differences in their scalings with respect to nanocube size and grafting density across the four phases. The phase diagram provided insights into tuning these interactions through the various parameters of the system for achieving target configurations. Overall, this work provides a framework for predicting and engineering interparticle configurations, with possible applications in plasmonic nanocomposites where control over particle orientation is critical.

Size and dimension dependent surface-enhanced Raman scattering properties of well-defined Ag nanocubes

Understanding the role of the morphology and particle–particle interactions on the plasmonic properties is of significant importance for the development of nanomaterials with excellent optical properties. However, the preparation of precisely defined nanomaterials with sizes that span a large range and their controllable self-assembly still remain a great challenge. Here, a multistep seed-mediated method has been established for preparing uniform Ag nanocubes over a broad size range from nanoscale (50nm) to microscale (1400nm) and with different hierarchical nanostructures range from “zero-dimension” (“0D”) to “three-dimension” (“3D”). The influence of the size and the interactions between the Ag nanocubes on their surface-enhanced Raman scattering (SERS) properties have been systematically and quantitatively investigated. It is demonstrated through experiments and finite-difference time-domain (FDTD) calculations that the SERS activity is dependent on the matching of the nanocube size to the excitation wavelength. The optimal combinations are 80, 110 and 130nm nanocubes with respect to 532, 638 and 785nm excitation wavelength, respectively. Furthermore, the Raman enhancement of the Ag nanocube hierarchical nanostructures increases rapidly from “0D” to “3D”, due to the extra increase of the hot spots that is attributed to the out-of-plane plasmonic coupling realized in the “3D” hierarchical nanostructures. This work clearly illustrates the quantitative role of the size and dimension of Ag nanocubes on their SERS properties and provides fundamental information for the design of advanced nanomaterials with higher SERS sensitivity.

Rabi Splitting in a Plasmonic Nanocavity Coupled to a WS2 Monolayer at Room Temperature

A large Rabi splitting (∼145 meV) is demonstrated in a plasmonic nanocavity coupled to a WS2 monolayer at room temperature. The nanocavity is composed of a silver nanocube and a silver film with an Al2O3 spacer of a few nanometers, which belongs to a nanoparticle on mirror (NPoM) type. The surface plasmon resonance (SPR) of the nanocavity can be tuned by controlling the thickness of nanogap and the size of silver nanocubes, which allows to successively adjust the SPR to accurately match the exciton energy of WS2 monolayers (2.02 eV). A mode splitting can be clearly observed from the dark-field scattering spectrum of the single hybrid nanocavity, which is ascribed to a strong coupling between the nanocavity mode and the excitonic mode. Furthermore, the anticrossing curves of the hybrid system are obtained by recording the scattering spectra with varied sizes of silver nanocubes, which further validate the interaction regime. It presents a strong coupling platform for two-dimensional monolayers, which is of...

A novel synthesis of Prussian blue nanocubes/biomass-derived nitrogen-doped porous carbon composite as a high-efficiency oxygen reduction reaction catalyst

Exploring efficient non-platinum catalysts for the oxygen reduction reaction (ORR) instead of platinum-based catalysts is vital for reducing costs of fuel cells or metal-air batteries. A Prussian blue/N-doped porous carbon (PB/NPC) nanocomposite catalyst for ORR was synthesized by a novel method of one-step high-temperature pyrolyzing the mixture of the casein extracted with ferric ions, potassium hydroxide and melamine. The PB nanocubes were embedded in the NPC, and the particle size of PB nanocubes was less than 100 nm. The presence of PB effectively reduced the production of hydrogen peroxide, and the PB/NPC catalyst exhibited high catalytic activity such as more positive onset-potential (of ∼0.93 V vs. RHE), large diffusion limiting current density (5.79 mA cm−2) close to Pt/XC-72 (20%) catalyst and good stability in alkaline media due to the stable binding structure and the synergistic effect of PB nanocubes and NPC. The synthetic strategy of the PB/NPC provides a facile and effective method for the preparation of non-platinum catalysts for energy conversion and storage applications.

Large-scale solvothermal synthesis of Ag nanocubes with high SERS activity

A novel solvothermal method has been developed to synthesize Ag nanocubes with controllable size. The PVP was used as the capping agent, ethylene glycol as reducing agent and glycerol as the viscosity regulator in the growth of Ag nanocubes. The high pressure generated from solvothermal condition favors the etching of Ag twin seeds and the formation of Ag single crystal seeds. Ag nanocubes with size ranging from 50 to 120 nm have been realized. The influence of glycerol, NaCl and PVP concentration, reaction temperature and time on the size and morphology of Ag nanocubes were analyzed and discussed. The Ag nanocubes have been found to be a high SERS-active substrate, and the detecting limit of thiram can reach as low as 10−9 M.

Size‐Dependent Visible Light Photocatalytic Performance of Cu2O Nanocubes

AbstractWell‐defined Cu2O nanocubes with tunable dimensions and physicochemical properties have been prepared using a simple one‐pot reaction. Reduction of Cu(II) salts by ascorbic acid in the presence of PEG as a structure‐directing agent affords crystalline Cu2O nanocubes of between 50 to 500 nm. Optical band gap, band energies, charge‐carrier lifetimes and surface oxidation state systematically evolve with nanocube size, and correlate well with visible light photocatalytic activity for aqueous phase phenol degradation and H2 production which are both directly proportional to size (doubling between 50 and 500 nm). HPLC reveals fumaric acid as the primary organic product of phenol degradation, and selectivity increases with nanocube size at the expense of toxic catechol. Apparent quantum efficiencies reach 26 % for phenol photodegradation and 1.2 % for H2 production using 500 nm Cu2O cubes.

One-step solid state synthesis of PtCo nanocubes/graphene nanocomposites as advanced oxygen reduction reaction electrocatalysts

Here, we report the synthesis of PtCo nanocubes with core–shell structure on graphene surface by a novel solid state method. Since no organic agent and surfactant was used during the synthesis process, the PtCo nanocubes surface is definite clean. The mean grain size of PtCo nanocubes is just about 5 nm, and PtCo nanocubes possess core-shell structure with PtCo core and a thin Pt-rich shell (about 3–5 atomic layers) on the surface. Compared with commercial Pt/C catalyst, the PtCo nanocubes exhibit an 8.4 times mass activity enhancement toward oxygen reduction reaction (ORR). Besides, the PtCo nanocubes show extreme high electrochemical durability.

DNA-Mediated Size-Selective Nanoparticle Assembly for Multiplexed Surface Encoding.

Multiplexed surface encoding is achieved by positioning two different sizes of gold nanocubes on gold surfaces with precisely defined locations for each particle via template-confined, DNA-mediated nanoparticle assembly. As a proof-of-concept demonstration, cubes with 86 and 63 nm edge lengths are assembled into arrangements that physically and spectrally encrypt two sets of patterns in the same location. These patterns can be decrypted by mapping the absorption intensity of the substrate at λ = 773 and 687 nm, respectively. This multiplexed encoding platform dramatically increases the sophistication and density of codes that can be written using colloidal nanoparticles, which may enable high-security, high-resolution encoding applications.

AgBr and AgCl nanoparticle doped TEMPO-oxidized microfiber cellulose as a starting material for antimicrobial filter

Present work covers the state-of-art progress in the advanced nanoarchitecture of organic-inorganic hybrid material; a starting material for the antimicrobial filter. TEMPO-mediated oxidation of microfiber cellulose was carried out to introduce the surface active carboxyl groups. Accordingly, qualitative and quantitative substitution of a functional group was investigated using FTIR, Solid state 13C CP/MAS NMR, and potentiometric titration; the reaction resulted to about 21.06% increase in carboxylate content. Further, the microwave irradiated (600 W) in-situ synthesis of AgBr and AgCl nanocubes were prepared and doped on carboxylated microfiber. The prepared AgBr@TO-MF and AgCl@TO-MF were tested using XRD, XPS, SEM and FTIR. With an average size of AgBr and AgCl nanocubes of around 200 ± 28 nm and 116 ± 10.73 nm. Whereas, AgBr@TO-MF and AgCl@TO-MF shown excellent antimicrobial activity against E. Coli and B. Subtilis, with MIC at around 200 μg/mL and 150 μg/mL, respectively. Fascinatingly, ICP-OES analysis estimated the silver leached was around 0.1 ppm.

High performance of visible-NIR broad spectral photocurrent application of monodisperse PbSe nanocubes decorated on rGO sheets

In this work, the photoresponse performance of monodisperse PbSe nanocubes in the range of visible and near-infrared (NIR) (400–1500 nm) regions was enhanced by reduced graphene oxide (rGO). A simple cost-effective method is presented to synthesize monodisperse PbSe nanocubes (NCs) that are decorated on the rGO sheets. By the addition of PbSe/rGO nanocomposites with different rGO concentrations, pristine PbSe NCs were synthesized with the same method. Microscopy images showed that the size of NCs was smaller than the exciton Bohr radius (46 nm) of PbSe bulk. Therefore, the UV-Vis-IR spectroscopy result revealed that the PbSe/rGO samples had absorption peaks in the NIR region around 1650 nm and showed a blue shift compared to the absorption peak of the PbSe bulk. J-V measurements of the samples indicated that monodisperse PbSe/rGO nanocomposites had a higher resistance than the other samples under dark condition. On the other hand, the resistance of the monodisperse PbSe/rGO nanocomposites decreased under different light source illuminations while the resistance of the other samples was increased under illumination. Photodetector measurements indicated that the monodisperse morphology of the PbSe NCs enhanced the photoresponse speed and photocurrent intensity. In addition, responsivity (R) and detectivity (D*) of the samples were higher in the NIR region.

Biphasic liquid interface derived magnetite nanocrystals: synthesis, properties and growth mechanism

Magnetite (Fe3O4) nanocubes were synthesized from a water-toluene biphasic liquid system. The Fe3O4 nuclei generated in aqueous phase were transferred into the toluene solution by modifying oleic acid (OLA) at the organic–inorganic interface. Well-dispersed Fe3O4 nanocubes with a size of 20 nm were prepared in this process. Octylamine was found to play a dominant role in controlling the dispersibility, morphology and particle size of nanocubes. Only alkylamine with proper chain length had effects on the morphology control in the biphasic liquid synthesis system. The remanence (7.04 emu g−1) and coercivity (170 Oe) of the nanocubes were 3 times higher than those (the remanence and coercivity value were 2.03 emu g−1 and 68 Oe) of irregular particles. Magnetite (Fe3O4) iron oxide nanoparticles can be used in various fields, including developing biomarker detection systems for disease diagnosis, ferrofluids, drug delivery, magnetic resonance imaging (MRI), energy storage, sensing, etc.

Sonochemical synthesis of Co2SnO4 nanocubes for supercapacitor applications

In this work, a simple sonochemical route was followed to synthesize cobalt stannate (Co2SnO4) nanocubes using stannous and cobalt chlorides as the precursors in alkaline medium at room temperature. The structure, composition and surface morphology of synthesized Co2SnO4 nanocubes have been characterized by using X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) indicates that the Co2SnO4 nanocubes are crystalline, single-phase without any impurity phase; the sizes of nanocubes are ∼100 nm. The cyclic voltammetry, galvanostatic charge-discharge cycling test, and electrochemical impedance spectroscopy (EIS) measurements are carried out for the Co2SnO4 nanocubes shows a specific capacitance 237 F g−1 at 0.5 mA cm−2 current density and in 1 M Na2SO4 electrolyte. Co2SnO4 nanocubes exhibit long cycling life with 80% retention of initial capacitance after 2000 cycles and the excellent rate capability at 15 mA cm−2 as much as 70% of that at 0.5 mA cm−2 suggest its potential use for supercapacitor applications.

Highly crystalline p-PbS thin films with tunable optical and hole transport parameters by chemical bath deposition

Lead sulfide (PbS) thin films, consisting of well faceted (up to 400 nm) cubic-nanocrystals and possessing significantly improved opto-electronic parameters essential for photovoltaic applications, are grown by utilizing chemical bath deposition (CBD) technique with bath concentrations of 10–200 mM. X-ray diffraction (XRD) and Raman studies confirm the highly crystalline and pure phase of PbS. FESEM and HRTEM studies show that all the films possess uniform and compact (111) oriented nanocubic morphology. Bath concentration change provides tunability of nanocube size from 100 to 400 nm and the direct optical band gap from 1.50 to 0.94 eV. The PbS films exhibit p-type semiconducting behavior with hitherto unreported concurrent highest mobility of 29.3 cm2V−1s−1 and high carrier concentration of ∼1018 cm−3 with the lowest room temperature resistivity of 0.26 Ω–cm. The 25 mM and 10 mM films show significant surface plasmon absorption in 1200–2400 nm range making them suitable as efficient infrared absorbers in excitonic and multi-junction solar cells.

Study on the thermal stability of Ce0.8Gd0.2O1.9 nanocubes on Al2O3 and SiO2 supports

The structural evolution of the Ce0.8Gd0.2O1.9 nanocubes supported on Al2O3 and SiO2 was investigated in oxidizing and reducing atmosphere over a temperature range up to 1100°C by XRD, TEM and SEM–EDS methods. The supported Ce0.8Gd0.2O1.9 particles preserved perfect cubic shape to 900°C in oxidizing atmosphere and to 750°C in a hydrogen atmosphere. No evidence of crystalline aluminate or silicate formation was observed for both supports during heating in oxidizing atmosphere up to 1100°C. However, for Ce0.8Gd0.2O1.9/SiO2 segregation of Gd3+ from the mixed oxide and its spreading over the silica surface was noticed at 1000°C–1100°C. Crystalline aluminate/silicate occurred in a hydrogen atmosphere already at 900°C. Apatite type (Ce,Gd)4.67(SiO4)3O mixed silicate was formed after reaction with SiO2 substrate, while monoclinic (Gd,Ce)4Al2O9 and tetragonal (Ce,Gd)AlO3 were formed on Al2O3. The (Gd,Ce)4Al2O9 phase became unstable at 950°C and transformed into (Ce,Gd)AlO3 aluminate, which was stable up to 1100°C. Various mechanisms of the solid-state reaction of mixed ceria with Al2O3 and SiO2 supports operate depending on the size of ceria nanocubes. Small particles (10–30nm) reacted as a whole with the support forming single crystal silicate or aluminate; at the same time, for bigger particles (30–80nm) reactions happen only near the boundary between the particle and the support.

Excellent green but less impressive blue luminescence from CsPbBr3 perovskite nanocubes and nanoplatelets

Green photoluminescence (PL) from CsPbBr3 nanocubes (∼11 nm edge-length) exhibits a high quantum yield (>80%), narrow spectral width (∼85 meV), and high reproducibility, along with a high molar extinction coefficient (3.5 × 106 M−1 cm−1) for lowest energy excitonic absorption. In order to obtain these combinations of excellent properties for blue (PL peak maximum, λmax < 500 nm) emitting samples, CsPbBr3 nanocubes and nanoplatelets with various dimensions were prepared. Systematic increases in both the optical gap and transition probability for radiative excitonic recombination (PL lifetime 3–7 ns), have been achieved with the decreasing size of nanocubes. A high quantum yield (>80%) was also maintained, but the spectral width increased and became asymmetric for blue emitting CsPbBr3 nanocubes. Furthermore, PL was unstable and irreproducible for samples with λmax ∼ 460 nm, exhibiting multiple features in the PL. These problems arise because smaller (<7 nm) CsPbBr3 nanocubes have a tendency to form nanoplatelets and nanorods, eventually yielding inhomogeneity in the shape and size of blue-emitting nanocrystals. Reaction conditions were then modified achieving nanoplatelets, with strong quantum confinement along the thickness of the platelets, yielding blue emission. But inhomogeneity in the thickness of the nanoplatelets again broadens the PL compared to green-emitting CsPbBr3 nanocubes. Therefore, unlike high quality green emitting CsPbBr3 nanocubes, blue emitting CsPbBr3 nanocrystals of any shape need to be improved further.