Zinc Acetate Precursor Research Articles

Rutherford Backscattering Spectrometry Analysis and Structural Properties of ZnxPb1-xS Thin Films Deposited by Chemical Spray Pyrolysis

Zinc lead sulphide ternary thin films were prepared by chemical spray pyrolysis on soda lime glass substrates using zinc acetate, lead acetate, and thiourea sources precursor. The films were characterized using Rutherford backscattering (RBS) spectrometry, energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), and X-ray diffractometry (XRD). RBS studies revealed variation in thickness and stoichiometry of the films with respect to compositional substitution between Zn and Pb, thereby giving effective composition ZnxPb1-xS, where x=0, 0.035, 0.069, 0.109, 0.176, and 0.217. Film thickness obtained by length conversion ranged from 81.02 nm to 90.03 nm. Microstructural analyses also indicated that the growth and particle distribution of the films were uniform across substrate’s surface. Diffraction studies showed that the films possess FCC crystalline structure. Crystallite size reduced from 14.28 to 9.8 nm with increase in Zn2+ in the ZnxPb1-xS samples.

Optimization of precursor based on optical, structural and magnetic properties of Cu-doped ZnO nanoparticles

Cu doped ZnO nanoparticles were synthesized via co-precipitation method using different precursors like zinc chloride, zinc acetate and zinc nitrate. The crystallite structure, morphology and optical properties were discussed by X-ray diffraction, scanning electron microscopy and UV–visible photo-spectrometer for different precursors. The hexagonal structure was confirmed by X-ray diffraction. The calculated average crystallite size from XRD spectra was low for zinc chloride precursor (22.3 nm) and high for zinc nitrate precursor (26 nm). The strong and transparent behaviour in the visible region of the sample using zinc nitrate precursor is due to the existence of less defects and enhanced crystal size which leads to the industrial applications especially as transparent electrode. The reduction in strain and the better crystallinity effectively depress interstitial defects. The energy gap is varied between 3.65 and 3.75 eV, where zinc nitrate precursor has Eg = 3.65 eV (minimum) and zinc acetate precursor has Eg = 3.75 eV (maximum). The observed higher energy gap using zinc chloride precursor could be attributed to the poor crystallinity and also the formation of the new compound based on Cu and Zn. The low energy gap for zinc nitrate precursor can be attributed to the better crystallinity with increasing grain size. Change in luminescence intensity and magnetization were discussed based on the defects formation and structural parameters.

Investigation of ethanol vapor sensing properties of ZnO flower-like nanostructures

ZnO flower-like nanostructures were synthesized using zinc nitrate, zinc acetate and zinc sulfate precursors by hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared analyses. All of the ZnO samples synthesized by the different precursors were crystallized in a same wurtzite hexagonal structure with different properties such as various morphologies, effective surface areas, concentrations of OH− surface groups, and gas sensing performances. It was observed that flower-like ZnO nanostructures grown by zinc nitrate and zinc acetate included nanopetals with thicknesses of 30 and 50nm, respectively. For the ZnO sample based on zinc sulfate, microspheres were constructed from nanoplatelets with thickness of ∼100nm. The gas sensing properties of the samples toward ethanol vapor were examined and compared at various working temperatures. It was observed that ZnO[nitrate] nanoflower sample was the optimal choice for practical applications (with considerable sensitivity of 70% beside fast response time of 25–27s at low working temperature of 130°C). The suitable ethanol sensing characteristics of ZnO[nitrate] sample was explained by its highly porous structure as the mean surface area of the samples calculated from BET method followed from ZnO[nitrate]>ZnO[acetate]>ZnO[sulfate] sequence.

Enzyme‐Mimicking Peptides to Catalytically Grow ZnO Nanocrystals in Non‐Aqueous Environments

AbstractThe application of enzymes for biomimetic material growth is a potential path to breakthroughs in catalytic inorganic nanocrystal synthesis because the biocatalytic functions of proteins can lead to highly efficient growth of materials with accurate structures at low temperature. However, many metal nanocrystals are grown in organic solvents, which is not an ideal environment for biomineralization with enzymes due to denaturing of catalytic pocket structures. Here, we applied a catalytic CP4 peptide, optimized for protease reactions such as amide and ester hydrolysis, to test the catalytic ZnO nanocrystal growth in non‐aqueous environments and the performance was compared with the enzyme subtilisin. We demonstrated that the CP4 catalytic peptide, evolved by the hydrogel‐based combinatory phage display library, could grow ZnO nanoparticles from zinc acetate precursors in higher crystallinity and yield, as compared to the protease enzyme, in an organic solvent by catalyzing ester‐elimination of precursors at room temperature. This result indicates that catalytic oligopeptides, which possess no rigid 3D structures but are rather flexible, could fold into the catalytically active conformation more frequently in harsh environments such as organic solvents.

UV photodecomposition of zinc acetate for the growth of ZnO nanowires

The thermal annealing of zinc precursors to form suitable seed layers for the growth of ZnO nanowires is common. However, the process is relatively long and involves high temperatures which limit substrate choice. In this study the use of a low temperature, ultra-violet (UV) exposure is demonstrated for photodecomposition of zinc acetate precursors to form suitable seed layers. Comparisons are made between ZnO nanowire growth performed on seed layers produced through thermal annealing and exposure to UV. The dependence of growth density and nanowire diameter on UV exposure time is investigated. Growth quality is confirmed with energy dispersive x-ray (EDX) and x-ray diffraction analyses. The chemical composition of the exposed layers is investigated with EDX and x-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) is utilized to investigate morphological changes with respect to UV exposure. The diameter and density of the resultant growth was found to be strongly dependent on the UV exposure time. UV exposure times of only 25–30 s led to maximum density of growth and minimum diameter, significantly faster than thermal annealing. EDX, XPS and AFM analyses of the seed layers confirmed decomposition of the zinc precursor and morphological changes which influenced the growth.

Simultaneous sonosynthesis and sonofabrication of N-doped ZnO/TiO2 core–shell nanocomposite on wool fabric: Introducing various properties specially nano photo bleaching

In this study, N-doped ZnO/TiO2 core–shell nanocomposite was successfully sonosynthesized and sonofabricated on wool fabric through a facile one-step method under ambient pressure and low temperature (75–80°C) as a novel photo-catalyst nanocomposite on textile material. The differences between crystalline phase transformation of conventional and ultrasound synthesized N-ZnO/TiO2 has been compared. The influence of different zinc acetate and titanium isopropoxide precursors in the formation of nanocomposite was studied and optimized through response surface methodology. The photocatalytic activity of the sonofabricated catalyst on the wool fabric surface was evaluated through decomposition of Methylene Blue as a model compound under sunlight irradiation. Also, N-doped ZnO/TiO2 nanocomposite sonosynthesized on wool fabric led to photo bleaching of wool fabric due to decomposition of the naturally occurred pigments under daylight irradiation. Further, yellowness index, antibacterial and antifungal activity against Escherichia coli, Staphylococcus aureus and Candida albicans, cell viability, char residual, alkali solubility, mechanical properties and water drop absorption time on the treated wool fabrics were evaluated. Also, the acid solubility of the synthesized nanopowder obtained from sonobath after treatment was characterized in acetic acid indicating higher acid resistance on N-doped ZnO/TiO2 nanocomposite.

Fabrication of Superhydrophobic Zinc Stearate Hierarchical Surfaces from Different Precursors

The fabrication of zinc stearate superhydrophobic hierarchical surfaces from two precursors by a simple wet chemical route and its wettability is reported. The zinc stearate coatings were prepared from a single pot using ethanolic solutions of zinc acetate/zinc nitrate and stearic acid. The coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, water contact angle, and sliding angle measurements. The coatings obtained from zinc acetate precursor showed superhydrophobicity (WCA >150°) even at lower precursor concentrations. The morphology of the coatings varied with the nature as well as the concentration of the precursors.

Tailoring ZnO nanostructures by spray pyrolysis and thermal annealing

We report a novel synthesis of ZnO nanorods with hexagonal pyramid-like heads by a simple and low cost technique of spray pyrolysis with the help of zinc acetate and tin (IV) chloride pentahydrate precursors. In the present study, the growth of ZnO nanorods is optimized by varying a number of sprays and annealing temperatures in the synthesis process. FESEM analysis reveals that ZnO nanorods are observed when the number of sprays exceeds 150 and film-like structure is observed below 150 sprays. Nanorods are formed when the molar ratio of zinc acetate to tin (IV) chloride pentahydrate in the solution mixture is 3:1. The optimum annealed temperature for the growth of nanorods is determined to be 350°C. The length and diameter of the vertically aligned nanorods are in the range of 1–3μm and 80nm, respectively. XRD diffraction patterns and HRTEM analysis confirm that the ZnO nanorods are single crystals with a preferred growth direction of [0001]. The effect of various growth parameters including molar ratio of zinc acetate to tin (IV) chloride pentahydrate in the mixture, number of sprays and annealing temperatures on the growth of ZnO nanorods are systematically studied. A plausible growth mechanism for hexagonal pyramidal heads of ZnO nanorods is discussed. These ZnO nanorods with hexagonal pyramid tips have potential application in photovoltaic devices.

Novel Green Route of Synthesis of ZnO Nanoparticles by Using Natural Biodegradable Polymer and Its Application as a Catalyst for Oxidation of Aldehydes

ZnO nanoparticles have been synthesized by using biodegradable natural biopolymer viz. Gum Tragacanth. This single step approach is very cost effective and reproducible. The reaction time and concentration of precursor zinc acetate play a major role in the nature and growth of ZnO nanoparticles. ZnO nanoparticles were characterized by X-ray diffraction, SEM, FTIR, EDAX, UV-visible spectroscopy and TEM. ZnO nanoparticles with 20-30 nm in diameter and hexagonal morphology were found; dispersed uniformly. Raman spectrum shows the mode E2 high at 437 cm−1 that is related to the vibration of wurtzite Zn-O bond in crystal structure of ZnO. The space between adjacent lattice fringes is ∼ sharp 2.42 Å. UV-visible absorption spectrum shows the sharp absorption band at 308 nm assigned to the intrinsic transition from valance band to conduction band. The ZnO nanoparticles display superior catalytic activity of conversion of aldehyde to acid as compared to bulk-ZnO material, because of high surface area of ZnO nanoparticles. A trace amount of ZnO nanoparticles catalyst required for organic conversion. The ZnO nanoparticles as catalyst are highly stable, recyclable and efficient in its activity.

Electrical Properties of CZO Films Prepared by Ultrasonic Spray Pyrolysis.

CuZnO (CZO) films have attracted increasing amounts of attention due to their promising potential applications in semiconductor devices. ZnO shows n-type conductivity, and attempts have been made to dope several elements in ZnO to improve the electrical properties. This study investigated the electrical property transitions of CZO films and determined the copper concentration at which the conductivity of CZO films will change from n-type to p-type. In this study, CZO films were fabricated by ultrasonic spray pyrolysis with copper acetate, zinc acetate, and ammonium acetate precursor solution. The concentrations of Cu ions in the CZO films were controlled by the concentration ratios of copper acetate to zinc acetate in the precursor solutions. In addition, these samples were analyzed by Hall effect measurements, X-ray diffraction, transmittance measurements, and photoluminescence measurements. The results show that the conductivity of the CZO film changes from n-type to p-type when the copper ion concentration in the film is 5%.

ZnO/TiO2 nanocomposite rods synthesized by microwave-assisted method for humidity sensor application

The nanocomposite rods shows well known properties compared with nano structured materials for various applications like light-emitting diodes, electron field emitters, solar cells, optoelectronics, sensors, transparent conductors and fabrication of nano devices. Present paper investigates the properties of ZnO/TiO2 nanocomposite rods. The bi component of ZnO/TiO2 nanocomposite rods was synthesized by microwave-assisted method which is very simple, rapid and uniform in heating. The frequency of microwaves 2.45GHz was used and temperature maintained 180°C. Zinc acetate and titanium isopropoxide precursors were used in the preparation. The obtained ZnO/TiO2 nanocomposite rods were annealed at 500°C and 600°C. ZnO/TiO2 nanocomposite rods have been characterized by X-ray Diffraction (XRD) for average crystallite size and phase of the composite material, Particle Size Analyser (PSA) for average particle size, Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) for morphology study, Energy Dispersive X-ray Spectrometry (EDX) for elemental analysis, and Thermal Gravimetric and Differential Thermal Analysis (TG–DTA) for thermal property.

Role of Nanostructures for Anti-proliferation of Bacteria and Their Quantitative Study Validated by Statistical Analysis

The simple and sensitive UV–visible spectrophotometric analytical methods have been adopted for the determination and validation of ZnO nanostructures (nanorods (NRs), nanosphere (NSs), and nanonuts (NNTs)), concentration, which are used to control the bacterial growth of Escherichia coli. This method is based on processing conditions of nanostructures of ZnO using precursors zinc acetate dihydrate (Zn(AC2)2·2H2O), zinc nitrate hexahydrate (Zn(NO3)2·6H2O), sodium hydroxide, hexamethylenetetramine (HMT), methanol, etc. The optical density (OD) of the resulting solution of ZnO nanostructures with E. coli bacteria were measured at 600 nm against the reagent blank, prepared under the same conditions. The use of statistical analysis for evaluation of the resulting solution (ZnO-NRs, ZnO-NSs, and ZnO-NNTs with E. coli) was optimized and validated by various operational parameters. Beer’s law was followed (Concentration range from 0.25–2.0 μg ml−1) with apparent molar absorptivity of 4.38 × 102 l mol−1 cm−1 for ZnO-NRs, 2.70 × 102 l mol−1 cm−1 for ZnO-NSs, and 3.10 × 102 l mol−1 cm−1 for ZnO-NNTs, respectively. The calibration curve shows linearity over the concentration range of 0.25–1.50 μg ml−1 for ZnO-NRs and 0.25–2.0 μg ml−1 for ZnO-NSs and ZnO-NNTs. Detection limit (LOD) and quantitation limit (LOQ) were found to be 0.022:0.068 μg ml−1 for ZnO-NRs, 0.028:0.087 μg ml−1 for ZnO-NSs, and 0.044:0.137 μg ml−1 for ZnO-NNTs analyzed by spectrophotometric method, respectively.

ZnO nanostructure thin films by continuous spray pyrolysis using doped precursor for Si solar cell application

This work presents deposition of Zn solution seed layer assisted growth of zinc oxide (ZnO) nanostructure layers by continuous spray pyrolysis reactor using lanthanides (Er and Eu) and metal (Al) influenced zinc acetate precursor solution. Dopants in precursors have influenced structural property, surface morphology and optical reflectance of resulting ZnO thin films which are supported by X-ray diffractometer, scanning electron microscope and reflectance measurements. Enhanced dispersion amongst nanorods is observed under the influence of Er and Al dopant in ZnO thin film. The change of precursor from Zinc acetate to Titanium tetraisopropoxide for Er doped precursor is helping to achieve better crystalline ZnO nanorods arrangement with increased homogenous growth, which results into improved light reflectance reduction of thin film. The experimental evidences of light reflectance from ZnO nanorods on Si surface is studied with the help of FDTD based Lumerical software package which can be a useful study for designing ZnO nanorods thin film in device purposes. The utility of ZnO layer by this reactor on low efficiency Si solar cell is also explored in improving device efficiency via increase of photocurrent.

Architecture of ZnO nanosheets and nanochips via zinc oxalato-hydrazinate complex

We report the synthesis of ZnO using a zinc oxalato-hydrazinate complex method. The zinc oxalato-hydrazinate complex was synthesized at room temperature using the precursors zinc acetate and oxalic acid. Thermogravimetric studies of zinc oxalato-hydrazinate showed complete phase formation of ZnO at 450 °C. The phase purity and formation of zinc oxalato-hydrazinate prepared in aqueous and organic solvents were confirmed by X-ray diffraction. The zinc oxalato-hydrazinate was calcined and decomposed at 450 °C to obtain phase-pure ZnO. XRD pattern of ZnO showed the existence of hexagonal wurtzite structure. Field emission scanning electron microscopy and transmission electron microscopy (TEM) demonstrate nanosheet-like morphology along with hexagonal nanoparticles. TEM images of aqueous-mediated ZnO clearly show nanosheets having dimensions 1 × 1.7 μ made up of hexagonal nanoparticles of size 10–25 nm. However, ZnO prepared in methanol showed bunch of uniform spherical particles. Further, ethylene glycol-mediated ZnO shows uniform well-aligned spherical particles with chip-like morphology. We have also performed the photocatalytic activity of ZnO samples for methylene blue degradation. The ethylene glycol-mediated ZnO showed extremely good activity (k = 6.44 × 10−2 min−1) compared to aqueous (k = 4.42 × 10−2 min−1)- and methanol (k = 2.92 × 10−2 min−1)-mediated ZnOs. The higher activity in ethylene glycol-mediated ZnO is due to lower size and good crystallinity.

Cytotoxicity of ZnO Nanoparticles Can Be Tailored by Modifying Their Surface Structure: A Green Chemistry Approach for Safer Nanomaterials.

ZnO nanoparticles (NP) are extensively used in numerous nanotechnology applications; however, they also happen to be one of the most toxic nanomaterials. This raises significant environmental and health concerns and calls for the need to develop new synthetic approaches to produce safer ZnO NP, while preserving their attractive optical, electronic, and structural properties. In this work, we demonstrate that the cytotoxicity of ZnO NP can be tailored by modifying their surface-bound chemical groups, while maintaining the core ZnO structure and related properties. Two equally sized (9.26 ± 0.11 nm) ZnO NP samples were synthesized from the same zinc acetate precursor using a forced hydrolysis process, and their surface chemical structures were modified by using different reaction solvents. X-ray diffraction and optical studies showed that the lattice parameters, optical properties, and band gap (3.44 eV) of the two ZnO NP samples were similar. However, FTIR spectroscopy showed significant differences in the surface structures and surface-bound chemical groups. This led to major differences in the zeta potential, hydrodynamic size, photocatalytic rate constant, and more importantly, their cytotoxic effects on Hut-78 cancer cells. The ZnO NP sample with the higher zeta potential and catalytic activity displayed a 1.5-fold stronger cytotoxic effect on cancer cells. These results suggest that by modifying the synthesis parameters/conditions and the surface chemical structures of the nanocrystals, their surface charge density, catalytic activity, and cytotoxicity can be tailored. This provides a green chemistry approach to produce safer ZnO NP.

Role of precursor material and annealing ambience on the physical properties of SILAR deposited ZnO films

ZnO thin films were deposited using a successive ionic layer adsorption and reaction (SILAR) method from three different precursors viz. zinc acetate, zinc sulfate and zinc chloride. All the films were annealed in air and vacuum ambiences at 350°C and characterized for their structural, optical, photoluminescence, electrical and surface morphological properties. The XRD profiles show that the crystalline quality of the films is improved after annealing in both the environments. It is found that the preferential orientation changes from (002) plane to (100) plane after atmospheric annealing for the films prepared from zinc acetate and zinc sulfate precursors, whereas no transition in preferential orientation is observed for films deposited from zinc chloride. Vacuum annealing does not affect the preferential orientation of all the three sets of films, but the intensities of diffraction peaks are increased remarkably. The films fabricated from zinc acetate and zinc sulfate precursors exhibit good average optical transmittance of 80% in the visible region after annealing whereas that deposited from zinc chloride exhibits only 70% transmittance. Compared with as-deposited and air annealed films, the vacuum annealed films exhibit lower electrical resistivity. An increase in the optical band gap and improvement in the surface morphology are also observed after annealing under both the ambiences for all the films, irrespective of the precursor used. The photoluminescence studies support the results on crystalline quality and optical band gap.

Structural, Optical and Electrical Properties of ZnO Thin Films Prepared by Spray Pyrolysis: Effect of Precursor Concentration

ZnO thin films have been prepared using zinc acetate precursor by spray pyrolytic decomposition of zinc acetate on glass substrates at 450 °C. Effect of precursor concentration on structural and optical properties has been investigated. ZnO films are polycrystalline with (002) plane as preferential orientation. The optical transmission spectrum shows that transmission increases with decrease in the concentration and the maximum transmission in visible region is about 95% for ZnO films prepared with 0·1 M. The direct bandgap value decreases from 3·37 to 3·19 eV, when the precursor concentration increases from 0·1 to 0·4 M. Photoluminescence spectra at room temperature show an ultraviolet (UV) emission at 3·26 eV and two visible emissions at 2·82 and 2·38 eV. Lowest resistivity is obtained at 2·09 Ω cm for 0·3 M. The current– voltage characteristic of the ZnO thin films were measured in dark and under UV illumination. The values of photocurrent and photoresponsivity at 5 V are increased with increase in precursor concentration and reaches to maximum value of 1148 μA and 0·287 A/W, respectively which is correlated to structural properties of ZnO thin films.

Removal of hazardous Ponceau S dye from industrial wastewater using nano-sized ZnO

The present work deals with the removal of Ponceau S dye from industrial wastewater using nano-sized semi-conductor ZnO as photocatalyst. The ZnO nanoparticles were synthesized by sol–gel method from precursor zinc acetate dihydrate. Effect of different parameters like catalyst concentration, dye concentration, pH, contact time, UV radiations and catalyst on the rate of photocatalytic degradation has been studied. Fourier transform infrared spectroscopy and X-ray diffraction were used for characterization of powdered material. The size of ZnO nanoparticles calculated is 20.6 nm.

Defect-controlled growth of ZnO nanostructures using its different zinc precursors and their application for effective photodegradation

Various zinc precursors, such as zinc acetate, zinc nitrate, zinc sulfate, and zinc chloride, have been used to control the formation of zinc oxide (ZnO) nanostructures onto aluminum substrate by chemical means. FESEM images of the ZnO nanostructures showed the formation of different morphologies, such as flakes, nanowalls, nanopetals, and nanodisks, when the nanostructures were synthesized using zinc acetate, zinc nitrate, zinc sulfate, and zinc chloride precursors, respectively. The TEM image of disk-like ZnO nanostructures formed using zinc chloride as a precursor revealed hexagonally shaped particles with an average diameter of 0.5 μm. Room-temperature photoluminescence (PL) spectra revealed a large quantity of surface oxygen defects in ZnO nanodisks grown from zinc chloride compared with those using other precursors. Furthermore, the ZnO nanostructures were evaluated for photocatalytic activity under ultraviolet (UV) light illumination. Nanostructures having a disk-like shape exhibited the highest photocatalytic performance (k = 0.027 min−1) for all the ZnO nanostructures studied. Improved photocatalytic activity of ZnO nanodisks was attributed to their large specific surface area (4.83 m2 g−1), surface oxygen defects, and super-hydrophilic nature of their surface, which is particularly suitable for dye adsorption.

Direct selective growth of ZnO nanowire arrays from inkjet-printed zinc acetate precursor on a heated substrate

Inkjet printing of functional materials has drawn tremendous interest as an alternative to the conventional photolithography-based microelectronics fabrication process development. We introduce direct selective nanowire array growth by inkjet printing of Zn acetate precursor ink patterning and subsequent hydrothermal ZnO local growth without nozzle clogging problem which frequently happens in nanoparticle inkjet printing. The proposed process can directly grow ZnO nanowires in any arbitrary patterned shape, and it is basically very fast, low cost, environmentally benign, and low temperature. Therefore, Zn acetate precursor inkjet printing-based direct nanowire local growth is expected to give extremely high flexibility in nanomaterial patterning for high-performance electronics fabrication especially at the development stage. As a proof of concept of the proposed method, ZnO nanowire network-based field effect transistors and ultraviolet photo-detectors were demonstrated by direct patterned grown ZnO nanowires as active layer.