PbS Nanoparticles Research Articles

PbS nanoparticles: biosynthesis and characterisation

A novel, green and highly reproducible yeast (Saccharomyces cerevisiae) mediated biosynthesis of PbS nanoparticles is reported. The synthesis is performed at room temperature in the laboratory ambience. X-ray and transmission electron microscopy are performed to ascertain the formation of PbS nanoparticles. Rietveld analysis of the X-ray data and SAED pattern indicated that PbS nanoparticles have face centred cubic unit cell structure. Individual nanoparticles almost spherical in shape having the sizes of 0.667 to 6.95 nm are found. UV-vis spectroscopic study revealed the surface plasmon resonance at 268 nm. The absorbance spectrum was used to estimate the value of optical band gap and particle size of PbS nanoparticles. A possible involved mechanism for the biosynthesis of PbS nanoparticles has also been proposed in which stress shearing response of the fungus seems to play an important role in the process.

PbS Nanoparticles: Synthesis, Supercritical Fluid Deposition, and Optical Studies

ABSTRACTLead sulfide (PbS) nanoparticles (NPs) of different sizes (2.0 nm - 14.4 nm) have been synthesized in our laboratory. By using those NPs, we formed colloidal films on glass and GaAs substrates employing a specialized supercritical fluid CO2 (sc-CO2) deposition method. The deposited films contain only the PbS NPs and the protecting group of oleic acids and require no polymer matrix. The NP films are solvent free, environmentally stable, and show good adhesion to the substrates. The sc-CO2 deposition process can deposit films ranging in thickness from a few monolayers, in well ordered arrays, up to 0.5 μm or greater. The photoluminescence (PL) properties of these nano-structured films were studied with Fourier transformation infrared spectroscopy from 5 K up to 300 K.

Mechanochemical solid-state transformations from a 3D lead(ii) chloride triazole carboxylate coordination polymer to its bromide/thiocyanate analogs via anion-replacements: precursors for the preparation of lead(ii) chloride/bromide/sulfide nanoparticles

Irreversible crystal-to-crystal transformations of 3D lead(II) coordination polymers with the ligand 1H-1,2,4-triazole-3-carboxylic acid (HL), from [Pb(L)(μ2-Cl)(H2O)]n (1) to [Pb(L)(μ2-Br)(H2O)]n (2) and [Pb(L)(μ1,1-NCS)(H2O)]n (3) by solid-state anion-replacement processes under mechanochemical reactions, have been studied. The thermal stabilities of compounds 1–3 were studied by thermogravimetric and differential thermal analyses. These irreversible solid-state structural transformations of compound 1 to compounds 2 and 3, have been verified by PXRD measurements. PbCl2, PbBr2 and PbS nanoparticles were obtained by thermal decomposition of compounds 1, 2 and 3 in oleic acid as surfactant at 200 °C under air atmosphere, respectively. These nanoparticles were characterized by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM).

Synthesis of anisotropic PbS nanoparticles using heterocyclic dithiocarbamate complexes

We report the synthesis of lead piperidine and lead tetrahydroquinoline dithiocarbamate (DTC) complexes and their use as single source precursors for the preparation of anisotropic PbS nanoparticles. The complexes were thermolysed in coordinating solvents such hexadecylamime (HDA), tri-n-octylphosphine oxide (TOPO), oleylamine (OA) and decylamine (DA) at various reaction temperatures. The variation of the reaction conditions and precursors produced PbS particles with shapes ranging from spheres to cubes and rods. The size of the particles is generally larger than those synthesized by conventional precursor routes. The electron microscopy and X-ray diffraction data confirm the particles to be very crystalline with the dominant cubic rock salt phase present in all samples.

Synthesis of Corrugated Structured N Type Pbs Thin Film

PbS thin films with corrugated structure were synthesized on glass substrates by dip coating. The surface of the films was found to be corrugated. XRD analysis confirmed the formation of crystalline PbS nanoparticles with average grain size 14nm. From thermo power measurements, the conductivity of the samples was found to be of n type. Band gap of the films was estimated as 1.7eV from absorption spectra.

Thermal Properties of TiO2/PbS Nanoparticle Solar Cells

Photovoltaic performance is shown to depend on ligand capping on PbS nanoparticle solar cells by varying the temperature between 140K and 350K. The thermal response of open-circuit voltage, short-circuit current density, fill-factor and shunt resistance varies between the ligands. A large increase in short-circuit current density at low temperatures is observed for 1,2-ethanedithiol and 3-mercaptopropionic acid and a relatively constant short-circuit current density is observed for the stiffer 1,4-benzenedithiol. Dark data provide evidence for tunnelling transport being the dominant charge conduction mechanism for all three ligand devices with recombination occurring within deep trap states. Under illumination, devices exhibit band-to-band recombination, indicated by an ideality factor of nearly unity.

1D CdS/PbS heterostructured nanowire synthesis using cation exchange

Heterostructured CdS nanowires with PbS deposits forming p-n junctions have been synthesized by successive cation exchange. The method developed herein opens up the possibility of preparing a spatially distributed heterojunction-based multifunctional electrode. The (photo)electrochemical activity of the material may be chemically tuned by changing the size and density of the p type PbS nanoparticles.

Growth of PbS nanoparticles and nanorods through a simple synthetic route: A mechanistic study of the thioglycerol-catalyzed hydrolysis of thiosulfate

Water-soluble PbS nanoparticles (NPs) and nanorods were grown using Pb(NO3)2 and Na2S2O3 as the precursors. Thioglycerol (TG) was shown to exhibit a catalytic role in the reaction and also acted as a capping agent. The solution pH plays an important role in nanocrystal growth, as higher pH leads to a higher release rate of S2−. This provides a way to control the nucleation growth processes. It was also demonstrated that dispersity of the obtained PbS NPs is related to the solution pH. PbS NPs with better water-solubility and narrower size distribution were produced by increasing the solution pH. The kinetics of hydrolysis of sodium thiosulfate has been examined.

A Dual Emissive BODIPY Dye and Its Use in Functionalizing Highly Monodispersed PbS Nanoparticles

A Dual Emissive BODIPY Dye and Its Use in Functionalizing Highly Monodispersed PbS Nanoparticles

A Dual Emissive BODIPY Dye and Its Use in Functionalizing Highly Monodispersed PbS Nanoparticles

A Dual Emissive BODIPY Dye and Its Use in Functionalizing Highly Monodispersed PbS Nanoparticles

Direct-writing of PbS nanoparticles inside transparent porous silica monoliths using pulsed femtosecond laser irradiation

Pulsed femtosecond laser irradiation at low repetition rate, without any annealing, has been used to localize the growth of PbS nanoparticles, for the first time, inside a transparent porous silica matrix prepared by a sol-gel route. Before the irradiation, the porous silica host has been soaked within a solution containing PbS precursors. The effect of the incident laser power on the particle size was studied. X-ray diffraction was used to identify the PbS crystallites inside the irradiated areas and to estimate the average particle size. The localized laser irradiation led to PbS crystallite size ranging between 4 and 8 nm, depending on the incident femtosecond laser power. The optical properties of the obtained PbS-silica nanocomposites have been investigated using absorption and photoluminescence spectroscopies. Finally, the stability of PbS nanoparticles embedded inside the host matrices has been followed as a function of time, and it has been shown that this stability depends on the nanoparticle mean size.

One-pot synthesis of lead sulfide nanoparticles

A convenient and effective one-pot three-component synthesis of the lead sulfide nanoparticles was developed on the basis of the exchange reaction between the lead acetate and sodium sulfide in water at the ambient conditions. A possibility was shown of the direct reaction between the lead Pb2+ and sulfide S2− ions in an aqueous solution, resulting in a solid phase which contained PbS nanoparticles only, avoiding the hydrolysis stage.

Near-infrared responsive PbS-sensitized photovoltaic photodetectors fabricated by thespin-assisted successive ionic layer adsorption and reaction method

A PbS-sensitized photovoltaic photodetector responsive to near-infrared (NIR) lightwas fabricated by depositing monolayered PbS nanoparticles on a mesoporousTiO2 (mp-TiO2) film via the spin-assisted successive ionic layer adsorption and reaction (SILAR) method.By adjusting the size and morphology of the PbS nanoparticles through repeatedspin-assisted SILAR cycles, the PbS-sensitized photovoltaic photodetector achieved anexternal quantum efficiency of 9.3% at 1140 nm wavelength and could process signals up to1 kHz.

Continuous laser direct-writing of PbS nanoparticles inside transparent silica monoliths

Direct space-selective growth of PbS nanoparticles, embedded inside a transparent porous sol–gel derived silica matrix, has been achieved using continuous laser irradiation. Before the irradiation, the porous silica host has been soaked in a PbS precursor solution. The effect of the concentration of PbS precursors and of the incident laser power on the mean particle size was studied. Absorption spectroscopy, X-ray diffraction analysis, and TEM measurements were used to identify the PbS crystallites inside the xerogel and to estimate the average particle size. It has been shown that PbS crystallite sizes range between 3 and 13 nm depending on the PbS precursors concentration.

Stability and recrystallization of PbS nanoparticles

The recrystallization and thermal stability of nanocrystalline lead sulfide have been studied by X-ray diffraction and scanning electron microscopy. PbS nanoparticles ranging in size from 10 to 20 nm were prepared by chemical precipitation from aqueous solutions. To assess the thermal stability of the size of PbS nanoparticles, the nanocrystalline powders were annealed in air or under dynamic vacuum (10−3 Pa) at a temperature varied from 433 to 930 K in 50-K steps. Annealing at temperatures of up to 700 K increases the particle size only slightly but relieves the lattice strain, suggesting that the nanocrystalline state of lead sulfide is thermally stable in this temperature range. The temperature range 700–900 K, where the particle size increases by a factor of 5–10, corresponds to the secondary recrystallization of nanocrystalline PbS. The temperature 700 K is half the melting temperature of macrocrystalline PbS, indicating that PbS nanoparticles have higher thermal stability in comparison with other nanomaterials.

Preparation and room temperature photoluminescence characterization of PbS/Si(100) thin films

Abstract PbS nanoparticles and smooth nanocrystalline thin films (nc-PbS) were prepared by chemical precipitation from aqueous solutions. Polyethylene oxide and isopropyl alcohol were used as additives in the aqueous solution, which results in the enhancement of the blue luminescence of PbS thin films. The introduction of isopropyl reduced the grain size and increases the optical gap of the PbS particles. The size of PbS particles was estimated to be ~ 3.5 nm. The broad emission bands exhibited were composed by a multiple overlapping peaks. The photoluminescence (PL) intensity was significantly influenced by the excitation wavelength. Indeed, intense blue luminescence was obtained under 230 nm compared to that obtained under 325 nm excitation wavelength. The PL emission from PbS nanoparticles was less intense than the luminescence of PbS thin films. The high PL intensity of the thin films was attributed to the lower density of defects introduced in the thin films during the chemical bath deposition growth process compared the defects density of PbS powder.

Green synthesis of lead sulfide nanoparticles by the lead resistant marine yeast, Rhodosporidium diobovatum

Biosynthesis of nanoparticles using microorganisms has attracted a lot of attention in recent years as this route has the potential to lead to synthesis of monodisperse nanoparticles. Here, we report the intracellular synthesis of stable lead sulfide nanoparticles by a marine yeast, Rhodosporidium diobovatum. The PbS nanoparticles were characterized by UV-visible absorption spectroscopy, X-ray diffraction (XRD) and energy dispersive atomic spectroscopy (EDAX). UV-visible absorption scan revealed a peak at 320 nm, a characteristic of the nanosize range. XRD confirmed the presence of PbS nanoparticles of cubic structure. Crystallite size as determined from transmission electron microscopy was found to be in the range of 2-5 nm. Elemental analysis by EDAX revealed the presence of particles composed of lead and sulfur in a 1:2 ratio indicating that PbS nanoparticles were capped by a sulfur-rich peptide. A quantitative study of lead uptake through atomic absorption spectrometry revealed that 55% of lead in the medium was accumulated in the exponential phase, whereas a further 35% was accumulated in the stationary phase; thus, the overall recovery of PbS nanoparticles was 90%. The lead-exposed yeast displayed a marked increase (280% over the control) in nonprotein thiols in the stationary phase.

Fabrication of PbS nanoparticle coated amorphous carbon nanotubes: Structural, thermal and field emission properties

A simple chemical route for the synthesis of PbS nanoparticle coated amorphous carbon nanotubes (aCNTs) was described. The nanocomposite was prepared from an aqueous suspension of acid functionalized aCNTs, lead acetate (PbAc), and thiourea (TU) at room temperature. The phase formation and composition of the samples were characterized by X-ray diffraction and energy dispersive analysis of X-ray studies. The Fourier transformed infrared spectra analysis revealed the attachment of PbS nanoparticles on the acid functionalized aCNT surfaces. Morphology of the samples was analyzed with a field emission scanning electron microscope. UV–Vis study also confirmed the attachment of PbS nanoparticles on the walls of aCNTs. Thermal gravimetric analysis showed that the PbS coated aCNTs are more thermally stable than functionalized aCNTs. The PbS coated aCNTs showed enhanced field emission properties with a turn-on field 3.34 V μm −1 and the result is comparable to that of pure crystalline CNTs.

Characteristic features of the energy spectrum and multiple exciton generation in nanoparticles of PbSe and PbS

This paper considers the formation of molecular terms of lead selenide and lead sulphide and shows a correlation between the molecular term structure and maximum quantum yield of a solar energy converter in the case of the multiexciton generation effect.

Selective and sensitive molecularly imprinted sol–gel film-based electrochemical sensor combining mercaptoacetic acid-modified PbS nanoparticles with Fe3O4@Au–multi-walled carbon nanotubes–chitosan

A sensitive molecularly imprinted electrochemical sensor was developed for selective detection of streptomycin by combination of mercaptoacetic acid-modified PbS nanoparticles with Au-coated Fe3O4 magnetic nanoparticles dispersed multi-walled carbon nanotubes doped chitosan film. The imprinted sensor was fabricated onto the Au electrode via stepwise modification of nanocomposites and an electrodeposited thin film of molecularly imprinted polymers via sol–gel technology. The morphologies and electrochemical behaviors of the imprinted sensor were characterized by scanning electron microscope, cyclic voltammetry, and differential pulse voltammetry, respectively. The prepared sensor showed very high recognition ability and selectivity for streptomycin. Under optimal conditions, the imprinted sensor displayed good electrocatalytic activity to the redox of streptomycin. And the differential voltammetric anodic peak current was linear to the logarithm of streptomycin concentration in the range from 1.0 × 10−6 to 1.0 × 10−3 mol L−1, and the detection limit obtained was 1.5 × 10−9 mol L−1. This proposed imprinted sensor was used successfully for streptomycin determination in different injection solution samples.