1D Nanorods Research Articles

Preparation and thermoelectric properties of inhomogeneous bismuth telluride alloyed nanorods

We herein report a large-scale hydrothermal synthesis of bismuth telluride nanorods. The effects of different additives, e.g. EDTA ligand, NH4Cl, SDBS and hydrazine hydrate, on the morphology of final product have been systematically investigated. The dimensional sizes of the resultant bismuth telluride alloyed (BTA) nanorods were around 500nm in length and 20nm in diameter. Different analytical methods were utilized to determine the chemical composition of the BTA nanorods. HRTEM observation revealed that the nanorods are not homogeneous in terms of composition along the c axis of each nanorod. The formation of such 1D nanorods was proposed to be closely related to the lattice stress caused by the spiral chain along the c axis of trigonal Te during the transition from one dimensional nanowires of Te template to BTA nanorods. To measure the thermoelectric properties of our products, the BTA nanorods were consolidated into bulk pellets by both spark plasma sintering (SPS) or high pressure and high temperature (HPHT) sintering. The corresponding maximal figure of merits (ZT values) for the pellets made by SPS and HPHT are 0.42 and 0.47 at 430K, respectively.

Material Diffusion and Doping of Mn in Wurtzite ZnSe Nanorods

Light-emitting transition metal ion doped 1D nanorods can be a suitable candidate for fabrication of the advanced opto-electronic-based nanodevices. Among various doped nanocrystals, Mn doped ZnSe nanocrystals are widely studied for their intense Mn d–d emission. However, this is mostly performed in the zinc blende phase of spherical ZnSe quantum dots. But, herein we study the strategy to dope Mn ions in wurtzite phase of 1D ZnSe nanorods. To achieve this, it is essential to control the 1D crystal growth of ZnSe to facilitate the adsorption of dopants. The anisotropic 1D nanostructures are designed following thermally controlled material diffusion process rather than the most widely expected kinetically driven crystal growth protocol, and the dopants are introduced at the appropriate stage of the growth for their adsorption. Using preformed magic size wurtzite ZnSe nanowires as the source material and fragmenting them at higher reaction temperature, ZnSe nanorods with variable aspect ratios are designed. ...

A Fast Sonochemical Method to Prepare 1D and 3D Nanostructures of Bismuth Sulfide

In this work, a sonochemical method to synthesize nanostructures of bismuth sulfide in 1D and 3D framework was developed and compared with a synthetic route with heating under reflux. The sonochemical method showed to be faster and more efficient than refluxing method to obtain nanostructures with high morphological homogeneity. Form and quality of the nanocrystals were dependent on the type of solvent employed in the synthesis procedure. 3D flower-like superstructures were obtained when ethylene glycol was used as solvent, while 1D nanorods were obtained when a mixture of dimethyl sulfoxide and ethylene glycol was used as solvent.

Methanol-induced formation of 1D poly(m-phenylenediamine) by conventional chemical oxidative polymerization exhibiting superior Ag+ adsorption ability

Morphology and size of poly(m-phenylenediamine) (PmPD) can be tuned readily with conventional chemical oxidation by introducing methanol (MeOH). Increasing MeOH content facilitates the formation of one-dimensional (1D) PmPD microstructures. Typically, when the MeOH content is up to 100%, 1D nanorods were formed, displaying the Ag+ absorbability of 2073 mg g−1.

Morphology-tailored synthesis of vertically aligned 1D WO3nano-structure films for highly enhanced electrochromic performance

We have demonstrated that vertically aligned WO3 nanostructure films can be fabricated on FTO-coated glass substrates using a template-free hydrothermal technique. Detailed mechanistic studies revealed that a variety of WO3 nanostructures—including nano-bricks, 1D nanorods and nanowires, and 3D nanorod-flowers—could be obtained by tuning the composition of the precursor solution, where the urea content and solvent composition played important roles in controlling the shape and size of the WO3 nanostructures, respectively. These nanostructured films exhibited enhanced electrochromic performance, and we drew a map for the correlation between the morphology and the electrochromic performance of the as-synthesized WO3 films. Due to the large tunnels in the hexagonally structured WO3, and the large active surface area available for electrochemical reactions, a large optical modulation of 66% at 632.8 nm and a potential of −2.0 V, fast switching speeds of 6.7 s and 3.4 s for coloration and bleaching, respectively, and a high coloration efficiency of 106.8 cm2 C−1 are achieved for the cylindrical nanorod array film.

Single-step synthesis of 3D nanostructured TiO2 as a scattering layer for vertically aligned 1D nanorod photoanodes and their dye-sensitized solar cell properties

In the present investigation we have successfully synthesized 1D vertically aligned rutile TiO2 nanorods (TNR) and 3D TiO2 nanostars (TNS) as a scattering layer by a single step hydrothermal route. The synthesized nanostructures were characterized by X-ray diffraction, scanning-and transmission electron microscopy and X-ray photoelectron spectroscopy. The 1D TiO2 nanorod and 3D TiO2 nanostar samples were further used for N-719 dye sensitized solar cells (DSSC) application. Compared to a nanorod based cell, the photovoltaic performance of the nanostars/nanorods TiO2 cell exhibits excellent DSSC performance, including superior light scattering, rapid electron transport and lower electron recombination rate. The 3D/1D TNS/TNR based DSSC cell exhibits 5.39% power conversion efficiency, which is remarkably higher than that of the bare 1D nanorod based (3.74%) photoelectrode. The detailed interface and transient properties of these nanorod and nanostar based photoanodes in DSSCs were analyzed by electrochemical impedance spectroscopy measurements and open circuit voltage decay measurements in order to understand the critical factors contributing to such high power conversion efficiency. The enhancement of the efficiency for the 3D/1D TNS/TNR photoanode based cell compared to the 1D TNR is mainly attributed to better light scattering capability, faster electron transport and lower electron recombination.

Controlled synthesis and thermal stability of hydroxyapatite hierarchical microstructures

Hydroxyapatite (HAp) hierarchical microstructures with novel 3D morphology were prepared through a template- and surfactant-free hydrothermal homogeneous precipitation method. Field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) were used to characterize the morphology and composition of the synthesized products. Interestingly, the obtained HAp with 3D structure is composed of one-dimensional (1D) nanorods or two-dimensional (2D) nanoribbons, and the length and morphology of these building blocks can be controlled through controlling the pH of the reaction. The building blocks are single crystalline and have different preferential orientation growth under different pH conditions. At low pH values, octacalcium phosphate (OCP) phase formed first and then transformed into HAp phase due to the increased pH value caused by the decomposition of urea. The investigation on the thermal stability reveals that the prepared HAp hierarchical microstructures are morphologically and structurally stable up to 800°C.

A highly efficient light capturing 2D (nanosheet)–1D (nanorod) combined hierarchical ZnO nanostructure for efficient quantum dot sensitized solar cells

A novel hierarchical ZnO nanostructure array composed of nanosheet branched (NB) ZnO nanorods (NRs) has been fabricated using a two-step solution reaction. The obtained nanosheet branched (NB) ZnO nanorods (NRs) exhibited considerably enhanced light capturing compared with ZnO thin films and ZnO nanorods. This combined 2D (nanosheet) and 1D (nanorod) hierarchical structure has significant potential as an efficient photoanode for quantum dot-sensitized solar cells (QDSSCs) because the nanosheets provide a large surface area for quantum dot loading and the nanorods present pathways for fast charge transfer. The CdSe/CdS co-sensitized QDSSCs using these nanosheet branched (NB) ZnO nanorods (NRs) as a photoanode exhibit a highly enhanced solar-energy conversion efficiency of 4.4% under conditions of 1 sun illumination.

Facile synthesis of NiCo2O4 nanorod arrays on Cu conductive substrates as superior anode materials for high-rate Li-ion batteries

In this work, we report a mild and cost-effective solution method to directly grow Ni-substituted Co3O4 (ternary NiCo2O4) nanorod arrays on Cu substrates. Electrochemical impedance spectroscopy (EIS) measurements show that the values of the electrolyte resistance Re and charge-transfer resistance Rct of NiCo2O4 are 6.8 and 63.5 Ω, respectively, which are significantly lower than those of binary Co3O4 (10.4 and 122.4 Ω). This EIS characterization strongly confirms that the ternary NiCo2O4 anode has much higher electrical conductivity than that of the binary Co3O4 electrode materials, which should greatly enhance the lithium storage performances. Due to the well-aligned 1D nanorod microstructure and a higher electrical conductivity, these ternary NiCo2O4 nanorod arrays manifest high specific capacity, excellent cycling stability (a high reversible capacity of about 830 mA h g−1 was achieved after 30 cycles at 0.5 C) and high rate capability (787, 695, 512, 254, 127 mA h g−1 at 1 C, 2 C, 6 C 50 C and 110 C, respectively).

Biological Templates for Antireflective Current Collectors for Photoelectrochemical Cell Applications

Three-dimensional (3D) structures such as nanowires, nanotubes, and nanorods have the potential to increase surface area, reduce light reflection, and shorten charge carrier transport distances. The assembly of such structures thus holds great promise for enhancing photoelectrochemical solar cell efficiency. In this study, genetically modified Tobacco mosaic virus (TMV1cys) was used to form self-assembling 3D nanorod current collectors and low light-reflecting surfaces. Photoactive CuO was subsequently deposited by sputtering onto these patterned nanostructures, and these structures were examined for photocurrent activity. CuO thicknesses of 520 nm on TMV1cys patterned current collectors produced the highest photocurrent density of 3.15 mA/cm(2) yet reported for a similar sized CuO system. Reflectivity measurements are in agreement with full-wave electromagnetic simulations, which can be used as a design tool for optimizing the CuO system. Thus the combined effects of reducing charge carrier transport distance, increasing surface area, and the suppression of light reflection make these virus-templated surfaces ideal for photoelectrochemical applications.

The effect of fabrication method of hierarchical 3D TiO2 nanorod spheres on photocatalytic pollutants degradation

The effect of fabrication method on the properties of hierarchical 3D TiO2 nanostructures was investigated by employing and developing both hydrothermal method and calcination method to synthesize hierarchical 3D TiO2 nanorod spheres in this study. A comprehensive comparison in terms of morphologies, crystallization, specific surface areas, light absorption capabilities, and photoluminescence spectrum was conducted between 3D TiO2 nanorod spheres synthesized via hydrothermal method and that synthesized via calcination method. A better photocatalytic activity was demonstrated over the TiO2 nanorod spheres synthesized through calcination method. This was ascribed to the better crystallization and monodispersion of the hierarchical 3D TiO2 nanorod spheres resulted from the calcination method; thus rendering it with more superior characteristics such as larger specific surface area, enhanced light absorption capability and faster transfer of electrons which suppress the recombination of photogenerated electrons and holes. This study is thus significant not only in promoting the development of hierarchical 3D TiO2 nanorod spheres via different methods, but also in revealing the effect of fabrication method on the photocatalytic activity of hierarchical 3D TiO2 nanorod spheres. The calcination method is proposed to be a facile and promising method for scale-up production of the hierarchical 3D TiO2 nanorod spheres with high photocatalytic activity for efficient pollutants degradation.

Microwave-assisted synthesis and characterisation of uniform LaPO4 nanorods

Lanthanum phosphate (LaPO4) phosphor materials with one-dimensional (1D) nanorods and nanoparticles were successfully synthesised from LaCl3 · 7H2O and Na3PO4 · 12H2O with pH adjusted at the range 1–6 using 37% HNO3 by the microwave radiation at 180 W for 60 min. X-ray diffraction patterns indicated that the as-synthesised products were hexagonal LaPO4 nanostructures. Scanning electron microscopy and transmission electron microscopy analyses showed that these products were nanoparticles, short and long nanorods, controlled by pH of the precursor solutions. Asymmetric stretching and bending vibrations of the groups were detected using Fourier transform-infrared spectroscopy. A possible formation mechanism of LaPO4 phosphor materials with 1D nanorods and nanoparticles was also proposed according to the experimental results.

ChemInform Abstract: Synthesis and Electrochemical Properties of Li3V2(PO4)3/C with One‐Dimensional (1D) Nanorod Structure for Cathode Materials of Lithium‐ion Batteries.

AbstractThe title cathode material is synthesized by a sol—gel method using maleic acid as a carbon source.

One‐Pot Radical Polymerization of One Inimer to Form One‐Dimensional Polymeric Nanomaterials

A one-pot polymerization strategy is put forward for producing 1D polymeric nanomaterials directly from a single inimer. An inimer bearing an NMP initiating site is polymerized in the presence of a RAFT CTA to form a pearl-necklace structure constituted of hyperbranched polymer "pearls". The obtained 1D nanorods show high regularity evidenced by the long-range order in small angle XRD patterns and the formation of liquid crystalline phases.

Controlled synthesis of porous nickel oxide nanostructures and their electrochemical capacitive behaviors

Achieving precise control over the synthesis and properties of porous nanostructured materials has been garnering considerable recent research attention. In the work presented here, nickel oxalate nanostructures with controllable shapes were synthesized through a simple and facile wet-chemistry route without any surfactant. An interesting shape evolution process from 2D nanoflakes to 1D nanorods has been illustrated on the basis of time-dependent experimental studies. Subsequent calcination at 380 °C yielded porous NiO nanostructures that retained the morphologies of their predecessors. The phase composition, morphology, and structure of the as-obtained products were studied by various tools. Electrochemical properties of the NiO electrodes were carried out using cyclic voltammetry and galvanostatic charge–discharge measurements by a three-electrode system. Electrochemical studies reveal that the as-prepared mesoporous NiO nanostructures have good specific capacitance and exhibit excellent capacity retention for more than 1,000 cycles due to its porous character and morphology. The results suggest that mesoporous NiO nanostructures are a promising supercapacitor electrode material.

Growth of self-assembled Mn, Sb and MnSb nanostructures on highly oriented pyrolytic graphite

The surface morphology of Mn, Sb and MnSb nanostructures grown on highly-oriented pyrolytic graphite (HOPG) has been studied in detail with scanning tunneling microscopy in ultrahigh vacuum. At the initial stage of growth, three dimensional (3D) clusters and islands of Mn, Sb and MnSb are formed at step edges and other defect sites. In middle stage, crystalline 2D islands and 1D nanorods of Sb can be observed together with crystalline 3D islands, whereas single- and double-layer cluster chains of Mn are obtained at room temperature (RT). MnSb crystallites form after deposition of both Mn and Sb on HOPG surface and annealing at T~375K. The ex-situ X-ray photoemission spectroscopy measurement revealed the formation of MnSb compound on graphite. Ferromagnetism was observed at RT for the 50-nm MnSb thin film using vibrating sample magnetometer.

Assembly of CuIn1-xGaxS2 Nanorods into Highly Ordered 2D and 3D Superstructures

Here, we report self- and directed assembly of CuIn(1-x)Ga(x)S(2) (CIGS) nanorods into highly ordered 2D and 3D superstructures. The assembly protocol is dictated by the ligand environment and is hence chemically tunable. Thiol capped nanorods spontaneously assemble into 3D aligned nanorod clusters over a period of hours with end to end and side to side order. These clusters can be disassembled by ligand exchange with an amine and subsequently reassembled either at a substrate interface or as free floating 2D sheets by directed assembly protocols. This dimensional control of CIGS nanorod assembly, extending over device scale areas with high degrees of order, is highly attractive for applications utilizing these important quaternary photoabsorbers.

Substrate dependent growth modes of ZnO nanorods grown by metalorganic chemical vapor deposition

Transmission electron microscopy studies were performed to reveal the underlying growth modes of ZnO nanorods by metalorganic chemical vapor deposition with respect to the type of substrates. On well-matched substrates, such as GaN/Al2O3 (0001) and ZnO (0001) substrates, a 2-dimensional (D) layer-by-layer growth occurs. During further growth after a certain critical thickness of ∼40nm, 1D nanorods start to grow on the 2D layer. In contrast, only vertically-aligned ZnO nanorods grow on a partially-matched substrate, such as Al2O3 (0001), after the coalescence of 3D ZnO islands. On mismatched substrates, such as Si (111) and Si (001), an Si–O amorphous layer of ∼5nm forms first, on which 3D ZnO islands grow. After their coalescence, 1D nanorods start to grow.

Tuning Growth of Low-Dimensional Organic Nanostructures for Efficient Optical Waveguide Applications

A novel amphiphilic porphyrin derivative DOCP-Zn has been synthesized and utilized to construct tunable nanostructures from 0D to 1D by controlling the axial coordination of zinc porphyrin with 4,4′-bipyridine. SEM images indicated that patterns between 0D nanospheres and 1D nanorods or nanoslices can be reversibly converted by the construction or destroy of the axial coordination interaction. This facile approach provided a new method for controlling the nanostructure morphologies and dimension by patterns conversion. The photoluminescence microscopy images indicated the 1D nanorods material has the potential application as nanoscale photonic elements.

Emission and Transmission Properties of a Doubly Resonant 3D Nanodisk Yagi–Uda Antenna for Wireless Optical Communications

In this paper, a novel doubly resonant three-dimensional (3D) nanodisk Yagi–Uda antenna, conceived for realizing wireless optical links within electronic circuits, is proposed. The prominent emitting properties of this nanoantenna have been deeply investigated both in the near and far field through a useful comparison with a more traditional 3D nanorod Yagi–Uda antenna. The behavior of the nanodisk antenna, both configured as a single nanoantenna and arranged in planar arrays, have been illustrated, emphasizing its improved performances with relation to crucial aspects as directional features, wavelength bands of operation, frequency tuning, and polarization influence on radiation. In particular, the single nanodisk antenna has been accurately designed to enhance the transmission feature in the near field at the wavelengths λ = 1.3 and λ = 1.55 μm. Also, the emission pattern of the array of nanodisk antennas has been properly tailored to ensure high peaks of directivity and narrow beam width in those ranges. Hence, efficient unidirectional angle patterns have been shaped for any operation wavelength and dimensions of the array, reaching extremely effective outcomes for a 3 × 3 array, which exhibits a maximum of directivity of 19 and 17.6 and −3 dB points at 18° and 21° for λ = 1.3 and λ = 1.55 μm, respectively.