PbS Nanostructures Research Articles

Synthesis of Star-Shaped Lead Sulfide (PbS) Nanomaterials and theirs Gas-Sensing Properties

Star-shaped PbS nanomaterials are synthesized by a hydrothermal method. Morphology and structure of the PbS nanomaterials are analyzed by SEM, HRTEM and XRD. Gas-sensing properties of the as-prepared PbS sensor are also systematically investigated. The results show star-shaped PbS nanostructure consists of four symmetric arms in the same plane and demonstrate good crystallinity. With the increase of ethanol concentration, the sensitivity of the PbS sensor significantly increases and demonstrates an almost linear relationship at the optimal operating temperature of 400 oC. Moreover, the fast response-recovery towards ethanol is also observed, which indicates its great potential on ethanol detection.

Synthesis of hierarchical PbS nanostructures capped with castor oil

We report the synthesis of castor oil capped hierarchical PbS nanostructures using piperidine dithiocarbamate of lead(II) complex as a single source precursor. The anisotropic structures of PbS were obtained at reaction temperatures of 190, 230, 270 and 300°C. The optical properties of the PbS nanostructures show evidence of quantum confinement.

Oriented self-assembly of PbS nanocrystals into 0D+1D ‘matchstick’ structures

We present a facile method to prepare a variety of Lead sulfide (PbS) anisotropic nanostructures, using aqueous solutions of Pb(NO3)2 and NaHS as precursors at room temperature. PbS nanostructures such as matchstick-, V- and rectangular-shaped were developed by an oriented attachment process, involving both spherical and cubic PbS nanoparticles, which were formed during the synthesis process. The nanostructures and oriented assembly were analyzed by Transmission Electron Microscopy. X-ray diffraction confirmed that PbS nanostructures were crystallized into the rock-salt structure. A brief description of the oriented self-assembly mechanism is provided too.

Stabilities and Reconstructions of Clean PbS and PbSe Surfaces: DFT Results and the Role of Dispersion Forces

Lead sulfide (PbS) and lead selenide (PbSe) are functional materials with manifold applications. In particular, nanocrystals and other nanostructures of PbS and PbSe are of mounting interest, which calls for a thorough understanding of the underlying crystal surfaces. Here, we present a comprehensive density-functional theory (DFT) survey of structures and stabilities for the (001), (011), and (111) surfaces of rocksalt-type PbS and PbSe. A representative set of possible reconstructions is explored for the polar (111) surfaces, allowing us to suggest both 2 × 1 and “octopolar” 2 × 2 motifs as favorable options; this agrees with previous experiments and could guide future ones. With regard to methodology, we address the role of dispersion interactions for studying PbS and PbSe surfaces: interestingly, the prediction of (001) surface energies depends crucially on the use of dispersion corrections to DFT, and the latter directly influences the computed equilibrium shapes (Wulff constructions). This study may...

Anisotropic growth and structure-dependent photoresponse activity of multi-level one-dimensional PbS nano-architectures

PbS nanostructures with three-fold hierarchy in 〈111〉 directions for designing optoelectronic devices.

Effect of silver doping on the current–voltage characteristic of PbS nanorods

We report on field emission property from a single nanorod measured by using scanning tunnelling spectroscopy. It has been shown that field emission from nanorods of small band gap semiconductor is significantly increasing by doping. The current transport mechanism is explained using double barrier tunnel junction formalism. It is observed experimentally that the Fowler–Nordheim tunnelling mechanism is dominant and governs the transport mechanism. The transport properties of PbS nanostructures in the form of nanorod are investigated in terms of various conduction mechanism. The minimum voltage necessary for triggering Fowler–Nordheim tunnelling under the revised biased for intrinsic sample ~0.95V and decreases to ~0.67V for increase doping concentration up to 1.76wt%.

Sonochemical Synthesis and Characterisation of Lead Sulfide Nanoparticles Using Different Capping Agents

Lead sulfide (PbS) nanoparticles of about 12 nm in diameter and with a single crystalline structure have been prepared by a sonochemical method. The influence of reaction time and different capping agents such as polyethylene glycol (PEG), cetylytrimethylammonium bromide (CTAB), tetraethylortosilicate on the morphology of the synthesised PbS nanoparticles have been investigated. Results revealed polyethylene glycol (PEG) was a useful capping agent to produce PbS nanostructures with a suitable size distribution. Further studies demonstrated that by increasing the polymer chain length of PEG, the size of the PbS nanoparticles decreased remarkably. The nanoparticles were characterised by X-ray diffraction, energy dispersive X-ray spectroscopy, and transmission electron microscopy and the surface areas were determined using the BET method.

Facile preparation of PbS nanostructures and PbS/f-CNT nanocomposites using xanthate as sulfur source: Thermal and optical characterization

PbS nanostructures with different morphologies were fabricated using a new sulfur source through a facile and low cost hydro(solvo)thermal method. The influence of different reaction factors such as sulfur source, temperature, reactant, solvent and surfactant on the size and morphology of the obtained PbS particles were investigated. Beside, a simple hydrothermal process at low temperature (60 °C) for little time (4 h), has been used for preparation of PbS nanoparticles (NPs)/functionalized multi wall carbon nanotubes (f-MWCNTs) nanocomposite. The as-prepared nanocomposite possesses excellent thermal and optical properties. Thermal stability increases by depositing PbS nanoparticles on the surface of CNT. The structure, morphology, thermal and optical properties of the as-prepared nanocompounds were studied by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy, Thermogravimetric analysis (TGA), Pl spectra and UV–Vis absorption spectra. Photoluminescence spectra of PbS NPs and nanocomposite are consist of two emission peaks which centered at around 402 and 423 nm, when excited at 350 nm. It was noteworthy that the blue luminescence intensity over PbS/f-CNT nanocomposite is very lower than that of pure PbS NPs. Remarkable blue-shift from bulk material was observed on the PbS nanoparticles using UV–Vis spectrum. Furthermore, possible growth mechanism of PbS nanostructures is presented.

NH3-assisted synthesis of PbS nanostructures: a novel hydrothermal method, structural and photocatalytic studies

In this work, lead sulfide nanostructures were successfully synthesized by a new one-step method via the gas-solution precipitation from lead(II) acetate and thiourea mixture solution in the ammonia atmosphere. The structure and morphology of the PbS nanostructures were determined by means of powder X-ray diffraction, field emission scanning electron microscopy and Fourier transformation infrared spectroscopy. Furthermore, the effects of contact time, final pH of reaction mixture, concentrations of reagents, temperature, and presence of surfactant on the purity, morphology and size of the as-prepared PbS were studied. Moreover, the photocatalytic activity of these nanostructures was also evaluated by decolorization yield of Congo red aqueous solution under ultraviolet irradiation.

Facile synthesis of PbS nanorods induced by concentration difference

This report describes a simple method to synthesize PbS nanorods by aqueous chemical method under ambient conditions without the surface-capping molecules or structure-directing templates. X-ray diffraction studies revealed that the prepared sample is a polycrystalline powder crystallized in face centered cubic (fcc) PbS structure with the crystallites orientated preferentially along the (200) direction. The SEM analysis shows the formation of PbS nanorods of width 80nm and length 410nm. The compositional analysis confirms the presence of Pb and S. The optical absorption study of PbS nanostructures shows the blue-shift with respect to those of the bulk counterpart due to quantum confinement effect. Electrical measurement reveals that the prepared PbS nanorods exhibits the semiconducting nature.

Influences of anionic and cationic dopants on the morphology and optical properties of PbS nanostructures

Selenium and zinc are used as anionic and cationic dopant elements to dope PbS nanostructures. The undoped and doped PbS nanostructures are grown using a thermal evaporation method. Scanning electron microscopy (SEM) results show similar morphologies for the undoped and doped PbS nanostructures. X-ray diffraction (XRD) patterns of three sets of the nanostructures indicate that these nanostructures each have a PbS structure with a cubic phase. Evidence of dopant incorporation is demonstrated by X-ray photoelectron spectroscopy (XPS). Raman spectra of the synthesized samples confirm the XRD results and indicate five Raman active modes, which relate to the PbS cubic phase for all the nanostructures. Room temperature photoluminescence (PL) and UV—Vis spectrometers are used to study optical properties of the undoped and doped PbS nanostructures. Optical characterization shows that emission and absorption peaks are in the infrared (IR) region of the electromagnetic spectrum for all PbS nanostructures. In addition, the optical studies of the doped PbS nanostructures reveal that the band gap of the Se-doped PbS is smaller, and the band gap of the Zn-doped PbS is bigger than the band gap of the undoped PbS nanostructures.

Effect of hydrogen gas on the growth process of PbS nanorods grown by a CVD method

PbS nanostructures were grown by sulfuration of two lead sheets in a tube furnace under nitrogen (N2) and argon/hydrogen (Ar/H2) conditions. All conditions, such as the sheet temperature, sulfur powder temperature, and the carrier gas rate, were the same for two samples. Field emission scanning electron microscope (FESEM) images showed that the nanostructures with rod morphology were formed on the sheets. However, the nanorods that were grown under N2 gas, were denser, more compact, and a different shape and size in comparison to another sample. In addition, the nanorods grown under N2 gas exhibited a rectangular shape, while another sample showed nanorods that were tapered. X-ray diffraction (XRD) patterns indicated that these nanorods were PbS with a cubic phase. Furthermore, Raman measurements confirmed the XRD results, and indicated three Raman active modes of PbS phase. The optical characterization results showed a band gap for the PbS nanorods in the infrared region.

Synthesis of PbS Nanostructures by Chemical Bath Deposition Method

Synthesis of PbS Nanostructures by Chemical Bath Deposition Method

Preparation of PbS and PbO nanopowders from new Pb(II)(saccharine) coordination polymers

Nanopowders and single crystal of new Pb(II) three-dimensional coordination polymer, [Pb(H2O)(μ-OAc)(μ-sac)]n “PASAC” were synthesized by a sonochemical and branched tube methods (Yılmaz et al., Z. Anorg. Allg. Chem. 629 (2003) 172). The new nano-structures of Pb(II) coordination polymer were characterized by X-ray crystallography analysis, scanning electron microscopy (SEM), X-ray powder diffraction (XRD), surface analysis (BET), and IR spectroscopy. The crystal structure of these compounds consists of three-dimensional polymeric units. The thermal stability of compounds was studied by thermal gravimetric analysis (TGA) and differential thermal analyses (DTA). PbS and PbO nano-structures were obtained by calcinations of the nano-structures of this coordination polymer at 600°C.

Large-scale and facial fabrication of PbS nanorods by sulfuration of a Pb sheet

PbS nanostructures were synthesized by sulfuration of lead sheets in a tube furnace under sulfur ambiance. The lead sheets were placed in different temperature zones, between 330 and 470°C. Field emission scanning electron microscope (FESEM) images showed that only the lead sheet placed at 330°C showed nanorods morphology. The prepared nanorods exhibited a rectangular shape with an average diameter of 95nm and an average length of 400nm. The phase and composition of the product were identified by x-ray diffraction (XRD) pattern and x-ray photoelectron spectra (XPS). The pattern indicated that these PbS nanorods were with a cubic phase and the XPS result showed binding energy for lead and sulfur that belonged to PbS structure. In addition, Raman measurements confirmed the XRD pattern and XPS results and indicated three Raman active modes, which belonged to PbS phase for the nanorods. The optical properties of the products were characterized by UV–visible and room temperature photoluminescence (PL) spectrometers. The optical characterization results showed a band gap for the PbS nanorods in the infrared region.

A facile and reliable route to prepare of flower shaped lead sulfide nanostructures from a new sulfur source

Flower shaped PbS nanostructures were prepared by the solvothermal method using propylene glycol and a new sulfuring agent. Novelty of this work is application of a new thio Schiff-base as complexing and sulfuring agent for synthesizing of PbS nanostructures. SEM and TEM was used to examine the surface morphology of the grown samples; also the products were characterized by XRD, SEAD, UV–vis and FT-IR spectra. The results of this paper indicate that the shape and size of lead sulfide nanocrystals can be controlled systematically by setting certain reaction parameters.

Morphology control and photovoltaic application of solvothermally synthesized PbS nanostructures

PbS nanostructures are synthesized using solvothermal method. Here, EDTA is employed as a chelating agent and PEG–PPG–PEG polymer as a structure directing surfactant. The possible factors behind the formation of nanostructures of various morphologies are explained. Crystalline quality is improved when EDTA is employed in the growth. In the Raman spectra, overtones of the longitudinal optical (LO) phonon peaks are observed. In the I–V characteristics of the photovoltaic devices, both open circuit voltage and short circuit current were improved as compared to the earlier devices made by using a similar mechanical pressing method with PbS nanowires.

Hierarchical nanostructures of PbS obtained in the presence of water soluble polymers

This study presents the generation of lead sulfide (PbS) nanocrystalline structures in the presence of water soluble polymers with different chemical structures. The PbS films were obtained by electrochemical deposition process on ITO glass substrate. The scanning electron microscopy (SEM) analysis revealed two types of PbS crystalline morphologies that form simultaneously, depending on the chemical structure of the polymer inducing the modification of the crystal growth mechanisms. The X-ray diffraction (XRD) analyses showed that PbS structures presented cubic crystallographic pattern.

Cage-like PbS nanostructure for the construction of novel glucose electrochemical biosensor

A novel glucose electrochemical biosensor was constructed based on the immobilization of glucose oxidase (GOx) in cage-like PbS nanostructure. The fabricated biosensor was characterized by scanning electron microscopy, UV–vis spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry, respectively. The direct electrochemistry of GOx at cage-like PbS nanostructure modified glassy carbon electrode was for the first time studied. The cage-like PbS nanostructure has larger surface area and provides a favorable microenvironment for facilitating the direct electron transfer between enzyme and electrode surface. The immobilized enzymes on PbS cage-like nanostructure retains its native structure and bioactivity and shows a surface controlled, reversible two-proton and two-electron transfer reaction with a apparent electron transfer rate constant of 2.85s−1. The biosensor shows wide linear range for glucose from 5.0×10−5M to 1.45×10−3M with high sensitivity of 11.02mAM−1cm−2. The detection limit was calculated to be 1.0×10−5M at signal-to-noise of 3. Moreover, the proposed glucose biosensor displays excellent selectivity, good reproducibility, and acceptable operational stability and can be successfully applied in the detection of glucose in serum sample. The cage-like PbS nanostructure provides a promising approach for immobilizing proteins and fabricating excellent biosensors.

Biomolecule-Assisted Synthesis of CoS Microclusters with Well-Aligned Nanoflakes

In this work, CoS flowerlike microclusters with well-aligned nanoflakes were synthesized using a facile solution-phase biomolecule-assisted approach in the presence of L-cysteine (an ordinary and cheap amino acid), which turned out to serve as both the S source and the directing molecule in the formation of cobalt sulfide nanostructures. The morphology, structure, and phase composition of the as-prepared CoS products were characterized using various techniques. The formation mechanism for the cobalt sulfide flowerlike assemblies with well-arranged nanoflakes was also discussed. This facile and solution-phase biomolecule-assisted method can be potentially extended to the preparation of other metal chalcogenides including NiS, PbS, MnS, FeS and CuS nanostructures.