Properties Of Zinc Oxide Nanoparticles Research Articles

Influence of Laser wavelength on morphological and optical properties of ZnO nanoparticles prepared by laser ablation in water

Nanoparticles (NPs) of Zinc oxide (ZnO) were prepared utilizing pulsed laser ablation of a Zinc metal plate in deionized water without utilizing surfactant. The effect of Laser wavelength on the characterization of ZnO was investigated. The 1064-nm and 532-nm wavelength beams produced from a Q-switched Nd: YAG laser at 10 ns pulse duration were employed. The SEM images displayed that the average diameter of the Zinc oxide NPs generated by the laser wavelength 532-nm are larger than the 1064-nm laser wavelength nanoparticles. Various sizes were observed of round ZnO nanoparticles in the SEM image. As the laser wavelength increased, the density of the nanoparticles in water increased. UV–vis analyses revealed that the absorption peak located at 342 nm (1064nm) and 344 nm (532nm). The nanoparticles formed at 1064 nm exhibited higher absorbance than the nanoparticles formed at 532 nm. The optical band gap is considered to be 3.42 eV for 1064 nm and 3.4 eV for 532 nm.

Investigating morphology-dependent antibacterial property of ZnO nanoparticles and developing an insight into oxidative stress generation and cellular response

In this work, morphology-dependent antibacterial property of zinc oxide nanoparticles (ZNPs) has been studied and an attempt has been made to investigate the reactive oxygen species generation potential of these nanoparticles. The antibacterial properties of ZnO nanorods with two different sizes have been quantitatively studied and their Minimum Inhibitory Concentration (MIC) has been determined against E.coli, a gram negative bacteria. It has been observed that ZNPs with smaller size exhibit better bacteriostatic and bactericidal properties. Furthermore, optical analysis has revealed that the smaller nanoparticles having greater efficiency to inhibit cell growth have higher density of surface defects and greater availability of free electrons and holes which leads to the generation of reactive oxygen species (ROS). To develop an insight into the oxidative microenvironment and the consequential cellular response, we have done the transcriptional analysis of oxidative stress gene sodA in ZNPs treated bacterial samples. Expression profile of the gene has been found to be ZNPs concentration dependent. An increase in the concentration of nanoparticles till MIC increased the expression level in a concentration dependent fashion. However beyond the MIC, the expression level of the gene is unexpectedly down-regulated reflecting the detrimental effect of higher levels of ROS on cellular components and metabolic activities. Thus through this study, we have tried to investigate the correlation between the surface morphology of ZNPs, production of ROS, growth-inhibiting activity and cellular response in this condition.

Biosynthesis of Zinc Oxide Nanoparticles Using Hertia intermedia and Evaluation of its Cytotoxic and Antimicrobial Activities

The unique properties of zinc oxide nanoparticles (ZnO-NPs) produced using plant extract make them attractive for use in medical as well as industrial applications. In this study, ZnO-NPs were synthesized using Hertia intermedia extract as the reducing and stabilizing agent followed by characterization and evaluation of its biological potency. Field emission scanning electron microscopy (FESEM) image showed spherical nanoparticles with a size range of 20–80 nm. UV-vis spectroscopy displayed absorption peaks at 362.67 nm which is one of the characteristic features of ZnO-NPs. FT-IR spectra confirmed the presence of some phytoconstituents as capping agents to stabilize the nanoparticles. MTT assay showed cytotoxicity of ZnO-NPs against Caco-2 (IC50 177 μg/mL), SH-SY5Y (IC50 184 μg/mL), MDA-MB-231 (IC50 168 μg/Ml, and HEK-293 (IC50 240 μg/mL) cell lines. Using 7-dichlorodihydrouorescein diacetate (DCFH-DA) assay, significant production of reactive oxygen species (ROS) was measured after 24 h of treatment with 200 μg/mL ZnO-NPs that is indicative of ZnO-NP-mediated oxidative stress. Induction of apoptosis/necrosis in ZnO-NPs-treated cells was determined using annexin V-PE/7-AAD staining. Furthermore, expression analysis of pro-apoptotic gene Bax and anti-apoptotic gene Bcl-2 by real-time PCR showed 10-fold increase in expression of Bax and 16-fold decrease in expression of Bcl-2 after exposure of cells to ZnO-NPs. Well diffusion method did not show effective antibacterial activities of synthesized ZnO-NPs against both gram-negative and gram-positive bacteria. All the results confirm that the ZnO-NPs synthesized in the present work are a potential candidate to induce ROS and oxidative stress that lead to cytotoxicity in cell lines.

Low-temperature synthesis of cadmium-doped zinc oxide nanosheets for enhanced sensing and environmental remediation applications

In the present study, we report the effect of Cd doping on the photocatalytic and photoluminescence properties of ZnO nanoparticles. Large scale synthesis of pure and Cd-doped zinc oxide (ZnO) nanoparticles was carried out by using the facile solution route at low temperature (60 °C). The synthesized products were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) attached with energy dispersive spectroscopy (EDS), UV–visible and photoluminescence spectroscopy. The detailed analysis revealed that the synthesized nanostructures were pure and well crystalline in nature and possessed wurtzite hexagonal crystal phase. Further photocatalytic results revealed that almost complete degradation of Rhodamine B (RhB) dye (10 ppm) occurred by 0.05 g of the 10% Cd-doped ZnO nanostructure within 110 min of UV exposure. In contrast, for pure ZnO, only 50% degradation of dye occured under the same set of conditions. Moreover, the photocatalytic degradation efficiency was increased with increase in the concentration of Cd2+ ions as a dopant. The better photodegradation efficiency of samples with an increase in dopant concentration was attributed to increase in the defects and reduction in bandgap width of ZnO nanoparticles. As-synthesized material was also explored as an efficient chemical sensor for the detection of hydrazine. A comparative study revealed a sharp decrease in the limit of detection for hydrazine sensing with the increased concentration of Cd2+ ions as a dopant. The Cd-doped ZnO nanomaterial also showed enhanced magnetism as compared to pure ZnO nanoparticles.

Synthesis and structural analysis of zinc oxide nano particle by chemical method

Abstract Nanoparticles of zinc oxides are synthesised by chemical methods taking as 1:4 M ratios ZnSO4.7H20 and NaOH. X-ray diffraction (XRD) and Raman Spectroscopy present the structural, chemical and optical properties of zinc oxide nanoparticles. Patterns from XRD show that the ZnO nanoparticles with a mean size 25 nm are made from a Wurtzite structure. Raman dispersion displays a sharp, strong E2 pitch, with a maximum of nearly 439 cm, which also lends a rootstock structure to nano-zinc oxide. It also adds nanoparticles (NPs) to their inherent toxicity, which is either totally overlooked or poorly investigated. The result of analysis shows a comparison of toxins and dangers derived from ZnO's chemical, physical and biological processes. In addition, the focus should be on developing environmentally compatible ZnO synthesis techniques, particularly organic approaches that remain relatively less dangerous then required to be enhanced with check of response situations in order to achieve the anticipated results and features.

Influence of nitrogen incorporation on the photocatalytic property of ZnO nanoparticles

Zinc oxide (ZnO) nanoparticles are deliberated as exceptional photocatalyst for organic pollutants degradation. However, their inefficacy under visible light poses a problem for industrial application. Thus, in this work, a route for the synthesis of nitrogen incorporated ZnO nanocomposites was proposed with urea as the nitrogen source. From XRD spectra, the complete incorporation of nitrogen into ZnO lattice was observed. The morphological study was performed using FESEM technique which revealed a major change in the morphology of ZnO nanoparticles after nitrogen incorporation from plate-like to flower-like structures, respectively. Existence of nitrogen in the sample was confirmed through EDX studies which revealed the occurrence of 1.1% nitrogen in the sample. Nitrogen incorporated ZnO nanocomposites exhibited better photocatalytic degradation of methylene blue dye (78%) than ZnO NP (48%) in aqueous medium under visible light illumination within 30 min.

A brief review on transition metal ion doped ZnO nanoparticles and its optoelectronic applications

Abstract Nanocrystalline materials have been the focus of the material scientists for the last few decades and with time, the interest on this field has been consistently increasing. Zinc oxide (ZnO) is one of the most important II-VI semiconducting material with wide band gap, whose nanostructures and nanoparticles have attracted the attention and research efforts of many material scientists due to its broad range of applications. Special characteristics, viz., chemical stability, anti-corrosion, anti-bacterial, heat-resistance, luminescence efficiency, electrophoretic nature, diversified yet selective sensing capabilities make it an interesting material to thoroughly explore. Efforts have been put to fine tune the structure, crystallinity etc using several synthesis methods for preparing ZnO nanoparticles for different applications. In this systematic review, we weigh in several methods of synthesis of ZnO nanoparticles and compare their usability in specific case scenarios. We also dive into the structural, chemical, optical, magnetic, sensing, and some of the biochemical properties of ZnO nanoparticles. We focus on enhancing the properties by doping the ZnO nanoparticles with transition metal (TM) atoms. Apart from the discussion on the physico-chemical properties, this review gives an in-depth idea on the technical issues such as growth and size modulation of the nano structures, band-gap engineering, and defects etc.

Modeling the Physical Properties of ZnO Nanoparticles with Selective Hydrogen Using DFT

The impact of hydrogen on the conductivity and vibration for zinc oxide (ZnO) nanoparticles had implicated for nanoscale optoelectronic units. Infrared reflectance spectra for ZnO hydrogen-annealed nanoparticles were calculated at incidence. The theory of density functional theory is applied to the reflectance model and absorption spectra. There is an agreement between both the model suggesting that the nanoparticles have inhomogeneous carriers’ concentrations and the experimental results. A significant decrease in carrier concentration resulted from exposure to oxygen for several hours, according to the adsorption on the nanoparticle surface of negative oxygen molecules. Also, the density of states in deferent wurtzoid’s size has been studied. The experimental energy gap values of bulk ZnO, HOMO and LUMO levels as a function of the total Zn and O atoms number in ZnOH diamondoids were determined, as well as the bond length in deferent wurtzoid’s size where the experimental ZnO bond length at 1.9767 Å has been calculated. The tetrahedral angles in deferent wurtzoid’s size were studied, deferent wurtzoid’s size Reduced mass as a vibration frequency function and force constant as a function of vibrational frequency in deferent wurtzoid’s size were determined. A good result for infrared as a vibration frequency function in deferent wurtzoid’s size has been found, as well as Raman as a vibration frequency function in deferent wurtzoid’s size.

Biosynthesis of Hydroxy Citric Acid Mediated Zinc Nanoparticles and Its Antioxidant and Cytotoxic Activity

Aim: To evaluate biosynthesis of hydroxy citric acid mediated zinc nanoparticle and its antioxidant and cytotoxic activity
 Introduction: Hydroxy citric acid is a chemical that is found in fruit rinds of Garcinia cambogia, Garcinia indica, and Garcinia atroviridis. Hydroxy citric acid is used to improve exercise performance and weight loss. Hydroxy citric acid can cause nausea, digestive tract discomfort, and headache when used short-term. Long-term safety is unknown.Zinc oxide nanoparticles are nanoparticles of zinc oxide that have diameters less than 100 nanometers. Zinc nanoparticles have a large surface area relative to their size and high catalytic activity. The exact physical and chemical properties of zinc oxide nanoparticles depend on the different ways they are synthesized. zinc oxide nanoparticles have also been shown to exhibit strong protein adsorption properties, which can be used to modulate cytotoxicity, metabolism or other cellular responses.
 Materials and Methods: Evaluation of anti-oxidant was done by DPPH activity and evaluation of cytotoxic activity was done by brine shrimp lethality assay. Colour changes was noted in evaluation of cytotoxic activity
 Results: The antioxidant activity was exhibited well at higher doses when compared to standard, but there was only 40% of cytotoxicity achieved which indicates its potential.Cytotoxic activity reveals that the drug showed a very good result at a concentration of 25 ul it showed a 40% of lethality thereby showing that Hydroxycitric acid medicated zinc oxide nanoparticles shows a potent activity when compared to that with the standard.
 Conclusion: The study concludes that hydroxy citric acid shows good antioxidant and cytotoxic activity.

Bio-fabricated bioactive arisaema triphyllum aqueous extract-loaded nano-ZnO particles improve the nursing care of esophageal cancer

Metal nanoparticles, synthesized using phyto-constituents, are one of the most economical and environmentally friendly materials. Biogenic zinc oxide nanoparticles (ZnONPs) obtained from Arisaema triphyllum plant extract were synthesized and characterized using UV-visible spectroscopy, XRD, TEM, and EDX. The presence of various plant extracts and the zinc oxide capping of ZnONPs was confirmed using UV-visible spectroscopy, further confirming the existence of ZnO in the 400–430 nm region based on its specific surface plasmon resonance. XRD patterns showed ZnONP-centered cubic crystalline assembly, while electron microscopy showed that the formation of spherical ZnONPs varied from ∼10 nm to 15 nm in diameter. Strong ZnONPs bands were established, as verified by EDX. The anticancer properties of ZnONPs prepared with different extracts were evaluated using esophageal cancer cells. High levels of anticancer activity against the two esophageal cancer cell lines, EC109 and TE8, were observed. The morphological changes of the esophageal cancer cells were evaluated using AO-EB and nuclear staining biochemical methods. Hemolysis assays with human erythrocytes showed excellent bio-compatibility with ZnONPs. To the best of our knowledge, this is the first study to report the use of A. triphyllum-loaded biogenic ZnONPs against esophageal cancer cells.

A fast-response and transparent solution–processed ultraviolet photodetector based on ZnO quantum–sized nanoparticles

Solution-processed ultraviolet (UV) photodetectors with high performance have great potential in many practical applications. In this paper, quantum-sized zinc oxide (ZnO) nanoparticles (~ 5.5 nm) were synthesized by a simple and low-cost chemical reflux method. The crystalline structure, morphologies, and optical properties of ZnO nanoparticles were investigated in detail. The results showed that the as-synthesized ZnO nanoparticles were wurtzite-structured (hexagonal) ZnO and had specific surface area as high as 68.3 m2/g, the ZnO nanoparticulate thin films had a strong absorption in UV region and optical bandgap of 3.28 eV. Furthermore, an UV photodetector was fabricated using the as-prepared ZnO nanoparticles, the device revealed stable, rapid and repeatable photoresponse towards 365 nm UV light, the sensitivity (S), responsivity (R), rise time (Tr), and decay time (Td) of the photodetector was 11.4 at − 0.25 V, 22.1 A/W at 3 V, 1.8 s and 47.2 s, respectively. In addition, the photoresponsive mechanism of this UV photodetector was systematically illuminated according to the adsorption-photodesorption theory of oxygen in ZnO nanoparticles.

Magnetic and optical investigation of Eumelanin-ZnO as organic-non-organic nanocomposite

Considerable interest has been devoted to zinc oxide (ZnO) based organic nanocomposites due to their exceptional properties. In this work, we investigated the structural, morphology, optical, and magnetic properties of ZnO nanoparticles doped with natural eumelanin (ZnO-Mel). The structural properties showed that the ZnO and ZnO-Mel nanocomposites have a wurtzite structure, and no secondary phase was detected, indicating that the doped natural eumelanin atoms are located within the ZnO host lattice. UV–vis measurements revealed that the band gap of ZnO increased upon incorporation of natural eumelanin. This study demonstrated that the ferromagnetic behavior of ZnO nanoparticles is a result of the incorporation of functional groups of natural eumelanin into the ZnO lattice, which changed only the properties of ZnO without changing its structure, as shown clearly by the XRD results. Changes in the properties of zinc oxide by the natural organic material eumelanin opens new horizons in organic-inorganic nanocomposites, which is a current challenge, and new applications in devices such as spintronic devices.

Synthesis and Antimicrobial Properties of Zinc Oxide Nanoparticles.

With increase in incidence of multidrug resistant pathogens, there is a demand to adapt newer approaches in order to combat these diseases as traditional therapy is insufficient for their treatment. Use of nanotechnology provides a promising alternative as antimicrobial agents as against traditional antibiotics. Metal oxides have been exploited for a long times for their antimicrobial properties. Zinc oxide nanoparticles (ZnO NPs) are preferred over other metal oxide nanoparticles because of their bio-compatible nature and excellent antibacterial potentials. The basic mechanism of bactericidal nature of ZnO nanoparticles includes physical contact between ZnO nanoparticles and the bacterial cell wall, generation of reactive oxygen species (ROS) as well as free radicals and release of Zn2+ ions. This review focuses on different synthesis methods of ZnO nanoparticles, various analytical techniques frequently used for testing antibacterial properties, mechanism explaining antibacterial nature of ZnO nanoparticles as well as different factors affecting the antibacterial properties.

ZnO Nanoparticle/Graphene Hybrid Photodetectors via Laser Fragmentation in Liquid.

By combining the enhanced photosensitive properties of zinc oxide nanoparticles and the excellent transport characteristics of graphene, UV-sensitive, solar-blind hybrid optoelectronic devices have been demonstrated. These hybrid devices offer high responsivity and gain, making them well suited for photodetector applications. Here, we report a hybrid ZnO nanoparticle/graphene phototransistor that exhibits a responsivity up to 4 × 104 AW−1 and gain of up to 1.3 × 105 with high UV wavelength selectivity. ZnO nanoparticles were synthesized by pulsed laser fragmentation in liquid to attain a simple, efficient, ligand-free method for nanoparticle fabrication. By combining simple fabrication processes with a promising device architecture, highly sensitive ZnO nanoparticle/graphene UV photodetectors were successfully demonstrated.

Effect of magnesium dopant on the structural, morphological and electrical properties of ZnO nanoparticles by sol–gel method

The undoped Zinc Oxide (ZnO) nanoparticles and Magnesium doped Zinc Oxide nanoparticles were produced by sol–gel method and the obtained nanoparticles were annealed at 400 °C. The effect of magnesium as dopant at various molar concentrations (Zn1-x Mgx O; x = 0, 0.2, 0.4) on the Structural, Optical, Morphological and Electrical properties were studied using X-ray diffraction (XRD), UV-Vis spectrophotometer, Photo luminescence, Field Emission Scanning Electron Microscope (FESEM) and Electron Impedance Spectroscopy. The XRD pattern confirms wurtzite structure without secondary phase in Mg substituted ZnO samples. Magnesium substitution decreases the crystallite size as the percentage of Magnesium is increased. Electrochemical impedance spectroscopy (EIS) was carried out to analyze the electrical properties of undoped ZnO and Magnesium doped Zinc Oxide nanoparticles.

Thermally influenced, optical and fluorescence properties of Zinc Oxide nanoparticles for glutathione sensing

Glutathione, a non-protein thiol molecule is present in abundance in the human body. It plays a major role in maintaining the intracellular redox states, metabolism and detoxification. A novel idea is introduced where zinc oxide nanoparticles are used for the fluorescence sensing of Glutathione. Zinc oxide nanoparticles prepared by the co-precipitation method has been annealed at 400 °C, 700 °C and 900 °C. XRD studies confirmed the evolution of phase and hexagonal wurtzite structure. FESEM images confirm the high degree of crystallinity. Optical absorption measurements exhibit a red shift in absorption for unannealed, 400 °C and 700 °C and a decrease in absorption wavelength for particle annealed at 900 °C. In addition, the bandgap energy decreases with an increase in annealing temperature indicating the increase in particle size. Photoluminescence studies in room temperature at an excitation of 330 nm show emission in the UV and visible regions. Quenching of fluorescence emission intensity due to electron transfer is noticed while increasing the concentration of Glutathione in nanomolar(nM) range. Quenching of PL intensity due to adsorption-induced electron transfer is explained through band bending effect. These results indicate that zinc oxide nanoparticles can be implemented for optoelectronics, solar photocatalysts and glutathione sensing applications.

Effect of Electron Injection Layer on the Parasitic Recombination at the Hole Transport Layer/Quantum Dot Interface in Quantum Dot Light-Emitting Diodes.

Zinc oxide (ZnO) nanoparticles layers are used as a substitute for organic electron transport layer due to high electron mobility, higher thermal stability and less sensitivity to the oxygen/moisture. In this study, we investigated the electron injection properties of ZnO nanoparticles in QLED compared with TPBi commonly used as injection layer in OLEDs. The expected electron injection barrier from energy diagram is similar in both devices, but the current density of the ZnO injection layer was slightly high compared with the TPBi injection layer. The current efficiency of ZnO and TPBi devices were 5.21 cd/A and 2.24 cd/A, respectively. The current efficiency of TPBi device is below half of ZnO device. We found that the electron-hole recombination occurs not only in the QD but also in the poly-TPD for TPBi device.

In Vitro Evaluation of Antibacterial Properties of Zinc Oxide Nanoparticles alone and in Combination with Antibiotics against Avian Pathogenic E. coli

In Vitro Evaluation of Antibacterial Properties of Zinc Oxide Nanoparticles alone and in Combination with Antibiotics against Avian Pathogenic E. coli

Parameters affecting carbofuran photocatalytic degradation in water using ZnO nanoparticles

AbstractCarbofuran photodegradation in water using zinc oxide nanoparticles as a catalyst was examined as well as some parameters influencing its percentage degradation rate such as zinc oxide load, initial concentration of carbofuran, the temperature of the reaction, the initial pH of the solution, and doping of zinc oxide nanoparticles with 5% (w:w) silver. Zinc oxide and Ag‐doped zinc oxide nanoparticles were produced using solvothermal and photoreduction methods, respectively, and silver doping effects on the structural, optical, and photocatalytic properties of zinc oxide nanoparticles were investigated using XRD, UV‐VIS spectrophotometer, TEM, SEM, SEM/EDX, and FTIR. The average diameter of the synthesized samples was 26.6, 30.55 nm for undoped zinc oxide and Ag‐doped zinc oxide, respectively. Zinc oxide doping with silver did not change the shape of the zinc oxide crystal, but decreased the reflection in the visible region, as well as the energy of the bandgap, and increased the zinc oxide photocatalytic activity.

Effects of Chromium Doping on the Electrical Properties of ZnO Nanoparticles

Nanostructured ZnO has gained a considerable amount of attention due to its unique physical and chemical properties and due to its remarkable performance in the fields of optics, photonics and electronics. The scope of this work is to study the Structural, Optical and Electronic properties of Pure Zinc Oxide (ZnO) and Chromium doped Zinc Oxide nanoparticles. These nanoparticles were synthesized by low-temperature precipitation method at various concentrations in the range (Zn1-xCrxO; (x = 0, 0.1& 0.3)). The precursors used were analytical grade Zinc Nitrate Hexahydrate and Chromium Nitrate Nona hydrate. The synthesized nanoparticles were annealed at 400°C. The Structural property of the synthesized nanoparticles was analysed by XRD (X-Ray diffraction) and was confirmed to exhibit a crystalline hexagonal wurtzite structure with an average crystallite size of 55nm. The functional groups were analysed using FTIR (Fourier Transformed Infra-red spectroscopy). The Morphology was analysed by FESEM (Field Emission Scanning Electron Microscope) and a change in morphology from spherical to spindle like structure was observed. The Optical properties were analysed using UV-Vis spectroscopy, the absorption spectrum for electromagnetic spectrum was observed and the changes in the optical band gap of ZnO nanoparticles with Chromium dopant addition were calculated to be in the range of 3.6 eV. The Electrical property of the synthesised nanoparticles was analysed using Electrochemical Impedance Spectroscopy (EIS) and the conductivity was calculated to be in the range of 1.1e-07S/m.