Composition Of ZnO Research Articles

ZnO thin films co-doped with III-valence metals and halogens: theory and experiment

The efficiency of metal-halogen co-doping of ZnO thin films deposited by DC magnetron sputtering of ceramic targets has been studied theoretically and experimentally. The influence of deposition temperature (300 − 900 K range), ZnX2 pressure (10−10−1 atm), Me2O3 dopant concentration (10−3 − 10 mol %), and Zn pressure (10−14 − 10−6 atm) on the composition of ZnO − Me2O3 − ZnX2 − Zn (Me = Al, Ga, In; X = F, Cl, Br, I) systems has been analyzed theoretically. The surface migration velocity of oxides and halides is also estimated for a wide temperature range. According to the calculation results, the optimal deposition conditions have been recommended. ZnO thin films co-doped with Al+Cl, Ga+Cl, Ga+Br, Ga+I, and In+Cl were deposited using ZnO:Me:X ceramic targets sintered by chemical vapor transport based on halides. The influence of the stoichiometric deviation of ceramic targets, the concentration of halogens, and metal impurities on thin films’ electrical, structural, compositional, and optical properties has been investigated. It is shown that Ga+Cl+Zn co-doping is the most promising. This co-doping increases both the structural perfection of films (electron mobility) and doping efficiency by Ga (charge carrier concentration), reducing the resistivity of thin films by two times compared to the use of classical ZnO:Ga ceramic targets. The optimal stoichiometric deviation of ZnO:Me:X ceramics targets, corresponding to the highest electron mobility and figure of merit of thin films, has been recommended.

Antimicrobial Packaging for Plum Tomatoes Based on ZnO Modified Low-Density Polyethylene.

Food safety and quality are major concerns in the food industry. Despite numerous studies, polyethylene remains one of the most used materials for packaging due to industry reluctance to invest in new technologies and equipment. Therefore, modifications to the current materials are easier to implement than adopting whole new solutions. Antibacterial activity can be induced in low-density polyethylene films only by adding antimicrobial agents. ZnO nanoparticles are well known for their strong antimicrobial activity, coupled with low toxicity and UV shielding capability. These characteristics recommend ZnO for the food industry. By incorporating such safe and dependable antimicrobial agents in the polyethylene matrix, we have obtained composite films able to inhibit microorganisms' growth that can be used as packaging materials. Here we report the obtaining of highly homogenous composite films with up to 5% ZnO by a melt mixing process at 150 °C for 10 min. The composite films present good transparency in the visible domain, permitting consumers to visualize the food, but have good UV barrier properties. The composite films exhibit good antimicrobial and antibiofilm activity from the lowest ZnO composition (1%), against both Gram-positive and Gram-negative bacterial strains. The homogenous dispersion of ZnO nanoparticles into the polyethylene matrix was assessed by Fourier transform infrared microscopy and scanning electron microscopy. The optimal mechanical barrier properties were obtained for composition with 3% ZnO. The thermal analysis indicates that the addition of ZnO nanoparticles has increased thermal stability by more than 100 °C. The UV-Vis spectra indicate a low transmittance in the UV domain, lower than 5%, making the films suitable for blocking photo-oxidation processes. The obtained films proved to be efficient packaging films, successfully preserving plum (Rome) tomatoes for up to 14 days.

Li/La and Cu modified ZnO semiconductor: Highly boosted of dielectric and sunlight-treatment of thiamethoxam and brilliant green contaminants

Solving the global environmental problem which related to the dissolved organic pollutants into water systems is an essential issue for human-health and aquatic life. This study represents the simple synthesis of new Li/La and Cu modified ZnO compositions as active photocatalysts and proper dielectric materials for electrical energy storage devices. The synthesized powders have one phase nature with hexagonal lattice indexed to ZnO structure. The field emission scanning electron microscopy (FESEM) clearly showed that (Li, La) modified ZnO powder consist of a mixture of particles having open hexagonal tube and spherical shapes. The FESEM picture of (Li, Cu, La) modified ZnO powder revealed lumps like cabbage shape mainly composed of pieces like sheets or papers. The purity and elemental composition were also verified by energy dispersive spectroscopy (EDS) analysis. The addition of (Li, La) and (Li, Cu, La) ions to ZnO semiconductor extremely improved the dielectric constant which is a benefit for application in solid state energy storage systems. (Li, Cu, La) modified ZnO sample is a suitable catalyst for removal of organic waste owing to its high response to visible light spectrum with measured band gap energy of 2.76 eV. The synergistic effect of Li+, Cu2+ and La3+ dopants induced high visible light photodegradation activities against thiamethoxam pesticide and brilliant green dye with measured efficiencies of 92 and 96 % after reaction time of 50 min, respectively. The high stability and mineralization properties of (Li, Cu, La) modified ZnO catalyst leads to the conclusion that this composition has a potential use in wastewater treatment.

Nanosheet assembled NiO-doped-ZnO flower-like sensors for highly sensitive hydrogen sulfide gas detection

Hydrogen sulfide (H2S) gas is a dual menace since it is not only hazardous to human health and the environment, but it is also flammable. Given these crucial considerations, the need for competent gas sensors for H2S detection becomes apparent. In this endeavor, an investigation of the gas-sensing prowess inherent in sensors made from assembled nanosheets of ZnO–NiO arranged into intricate flower-like structures. The sensing materials were prepared using a straightforward solvothermal process. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to thoroughly examine the sensor's chemical properties and structural composition. The gas-sensing abilities of the sensing materials were rigorously assessed, which included a close examination of their electrical response to varied concentrations of H2S. The efficacy of the sensors may be due to the synergistic interactions between their distinct flower-like design, endowing them with an expansive surface area for optimum gas adsorption, and the significant catalytic impact supplied by the composition of ZnO–NiO. The results show that the ZnO–NiO flower-like sensors have high sensitivity, selectivity, and stability to H2S gas. Within the studied range, the response and recovery times were 51.43 s and 38.11 s respectively at 250 °C in 100 ppm H2S. This amalgamation of attributes manifests as an enhancement in the sensors' gas-sensing capabilities, highlighting their suitability for such an application. This research complements the explanation offered by first-principles calculations based on Density Functional Theory (DFT) to dive into the fundamentals of this gas-sensing mechanism.

Fabrication of Z-scheme ZnO/g-C3N4/ZnS nanocomposites using high power laser for methylene blue degradation

Photocatalysis plays a vital role in addressing environmental challenges by harnessing solar energy for efficient pollutant degradation. In this study, we investigate the photocatalytic activity of a ZnO/g-C3N4/ZnS composite system in the degradation of methylene blue, a widely used dye with detrimental effects on aquatic ecosystems. The composite materials were synthesized using a facile and scalable approach, and their structural properties, morphologies, sizes, and elemental compositions were characterized using different analytical techniques. The ZnO/g-C3N4/ZnS composite exhibited enhanced photocatalytic performance compared to individual components. Remarkably, the degradation efficiency reached 80% for the composite with a 30% ZnO composition, surpassing the efficiencies of ZnS alone (29%) and ZnS/g-C3N4 (65%). The composite’s higher degradation efficiency is due to synergistic semiconductor effects, enhancing charge transfer and reducing electron–hole recombination. ZnO incorporation increases active sites and surface area, improving interaction with methylene blue. The favorable band edge positions of ZnO aligned with ZnS and g-C3N4, facilitating the utilization of a broader spectrum of solar light. The composite’s photocatalytic activity was achieved under UV light irradiation, demonstrating its potential for sustainable and energy-efficient applications. This study highlights the significance of composite design and the Z-scheme concept in photocatalysis, offering insights into the development of advanced materials for environmental remediation. The findings contribute to the understanding of efficient solar-driven pollutant degradation and pave the way for the design and optimization of innovative photocatalytic systems for sustainable environmental solutions.

Evaluation of Developmental Toxicity and Oxidative Stress Caused by Zinc Oxide Nanoparticles in Zebra Fish Embryos/ Larvae.

Zinc oxide nanoparticles (ZnO NPs) are used in various fields, including biological ones. ZnO NPs are eventually disposed of in the environment where they may affect natural systems, and there is no international law to regulate their manufacture, usage, and disposal. Hence, this present study is carried out to synthesise a more non-toxic and bioactive ZnO NPs from the marine algae Sargassum polycystum. The ZnO NPs were biologically produced using the marine algae Sargassum polycystum. The dynamic light scattering result describes that synthesised particles'average size is about 100nm in diameter. Transmission electron microscopy (TEM) analysis demonstrated the rod-like morphology of ZnO NPs. Fourier tranform-infrared spectroscopy (FT-IR) results revealed the presence of functional groups in ZnO NPs. The selected area electron diffraction (SAED) results strongly suggested the ZnO NPs crystallinity. ZnO NPs surface morphology and compositions were identified by scanning electron microscopy (SEM- EDX) values. To analyse the toxicity of synthesised nanoparticles, zebra fish larvae were used, which involved subjecting embryos to various ZnO NPs concentrations at 1 hpf and analysing the results at 96 hpf. The 60 and 80 ppm sub-lethal doses were chosen for further studies based on the LC50 (82.23 ppm). In the ZnO NPs-treated groups, a significant slowdown in pulse rate and a delay in hatching were seen, both of which impacted the embryonic processes. A teratogenic study revealed a dose-dependent increase in the incidence of developmental deformities in the treated groups. Along with increased oxidants and a corresponding reduction in antioxidant enzymes, Na+ K+-ATPase and AChE activity changes were seen in ZnO NPs-treated zebra fish larvae groups. The apoptosis process was increased in ZnO NPs-treated groups revealed by acridine orange staining. These results indicate that the green synthesis process cannot mitigate the oxidative stress induced by ZnO NPs on oxidative signalling.

An amperometric sensor based on gamma-irradiated PANI-ZnO-NiO nanocomposite thin films for Escherichia coli detection in water

Purpose Regular monitoring of bacteria, especially Escherichia coli, in wastewater is crucial to ensure the maintenance of public health. Amperometric detection proves to be a fast, sensitive and economically viable solution for E. coli enumeration. This paper reported a prototype amperometric sensor based on PANI-ZnO-NiO nanocomposite thin films prepared by sol–gel method and irradiated with gamma ray. The purpose of this study is to investigate the sensor performance of PANI-ZnO-NiO nanocomposite thin films to detect E. coli in water. Design/methodology/approach The films were varied with different compositions of ZnO and NiO by using the formula PANI-(ZnO)1-x-(NiO)x, with x = 0.2, 0.4, 0.6 and 0.8. PANI-ZnO-NiO nanocomposite thin films were characterized by using X-ray diffraction (XRD) and atomic force microscopy (AFM) to study the crystallinity and surface morphology of the films. The sensor performance was conducted using the current–voltage (I-V) measurement by testing the films in clean water and E. coli solution. Findings XRD diffractograms show the peaks of ZnO (1 0 0) and NiO (1 0 2). AFM analysis shows the surface roughness, and the grain size of PANI-ZnO-NiO thin films decreases when the concentration ratios of NiO increased. I-V curves show the difference in current flow, where the current in E. coli solution is higher than the clean water. Originality/value PANI-(ZnO)1-x-(NiO)x nanocomposite thin film with the highest concentration of ZnO performed the highest sensitivity among the other concentrations, which can be used to indicate the presence of E. coli bacteria in water.

Study of electronic, thermoelectric, and optical response of zinc oxynitride thin films

In this research work, we have used density functional theory (DFT) and experimental approaches to explore the impact of nitrogen substitution on the electronic, thermoelectric, optical and structural aspects of Zn Ox=1−y Ny compounds with varying dopant content. The ZnO band gap was shown to progressively decrease with the successive increases in N concentration in theoretical and experimental estimated results. The thermoelectric properties of pristine and N-doped ZnO compositions were analyzed by employing Boltztrap measurements. The structural, morphological, and optical properties of sputtered thin films were studied extensively. X-ray diffraction studies exhibited the monophasic hexagonal wurtzite structure without any secondary phase. Field emission scanning electron microscopy was performed to examine the surface morphologies of the prepared thin films, which depicted that the higher dopant content caused grain agglomeration. Optical parameters were extracted using spectroscopic ellipsometry measurements and the optical band gap was inferred using Tauc plot. Importantly, the sample having maximum dopant content revealed tunable ENZ response in the NIR region. It is anticipated from computed simulation and experimental outcomes that the electronic, optical, and thermoelectric behavior of ZnO compounds could be enhanced by ensuing nitrogen inclusion. These engineered materials would be well-suited for optoelectronic applications within the visible and near-infrared energy regions as well as in thermoelectric applications.

Synthesis of strontium oxide-zinc oxide nanocomposites by Co-precipitation method and its application for degradation of malachite green dye under direct sunlight

Photocatalysts workable under direct sunlight are the safe and cost-effective option for water purification. The nanocomposites of strontium oxide and zinc oxide (SZ NCs) were synthesized using coprecipitation method. The respective precursors of SZ NCs were subjected to alkaline hydrolysis and subsequently thermally treated to yield SZ NCs. The SZ NCs with different ZnO composition was synthesized by varying the concentration of ZnO precursor from 0.2 to 1 M. The structural properties of SZ NCs evaluated using X-Ray diffraction (XRD), Thermogravimetric analysis (TGA), and Differential thermal analysis DTA). The optical properties of SZ NCs studied using ultraviolet–visible (UV–Vis) spectroscopic study. The trend observed in the intensity of XRD peaks indicated the occurrence of Zn doping in the crystalline lattice of SrO and the formation of SrO–ZnO composite. Upon incorporation of 1 M of ZnO precursor, the grain size of the SrO was decreased from 49.3 to 27.6 nm. The weight loss in the thermal analysis indicates the removal of carbonates from the sample upon heating and shows the formation of an oxide structure. UV–Vis spectra confirmed that the presence of SrO enhanced the sunlight absorption of SZ NCs. The increase in the composition of ZnO precursors increased the bandgap of SrO (2.09 eV) to the level of ZnO (3.14 eV). SZ NCs exhibited heterostructure morphology, where the nanosized domains with varying shapes (layered and rod-like) were observed. Under direct sunlight conditions, SZ NCs prepared using 1 M/0.6 M of SrO/ZnO precursors exhibited 15–20 % higher photocatalytic efficiency than neat SrO and ZnO. In precise, 1 mg of this SZ NC was degraded 98 % of malachite green dye dissolved in water (10 ppm) under direct sunlight. Additionally, the thermal stability results showed that 18 % decomposition was obtained due to the degradation impurities in SrO/ZnO catalysts and the XRD results revealed that no structural change is obtained in SrO/ZnO photocatalysts after stability test. The SZ NCs can be effectively used as safe and economic sunlight photocatalysts for water purification in remote areas without the electricity.

An Insight into Synergistic Metal-Oxide Interaction in CO2 Hydrogenation to Methanol over Cu/ZnO/ZrO2

The metal-oxide interaction is of significance to the construction of active sites for Cu-catalyzed CO2 hydrogenation to methanol. This study examines the effect of ZnO and ZrO2 composition on the Cu/ZnO/ZrO2 catalyst structure and surface properties to further tune the catalytic activity for methanol synthesis. The ZnO/ZrO2 ratio can impact the CuZn alloy formation from strong Cu-ZnO interactions and the surface basic sites for CO2 adsorption at the Cu-ZrO2 interface. The proportional correlation of the CuZn alloy content and CO2 desorption amount with the space-time yield (STY) of methanol reveals a synergistic interaction between Cu and oxides (ZnO and ZrO2) that enhances methanol synthesis. The optimized Cu/ZnO/ZrO2 catalyst exhibits higher STY relative to the traditional Cu/ZnO/Al2O3 catalyst. The obtained results presented herein can provide insight into the catalyst design for methanol synthesis from CO2.

Efficiency Dependence of Radiation-Assisted Ceramic Synthesis Based on Metal Oxides and Fluorides on Initial Powder Particle Sizes

The study is devoted to investigating the efficiency dependence of radiation-assisted ceramic synthesis based on metal oxides and fluorides on initial powder particle sizes. The synthesis was performed for 30 series of ceramic samples, including MgO, Al2O3, ZnO, ZrO2, MgF2, and complex compositions: cerium-activated yttrium-aluminum garnet (Y3Al5O12), spinel AlMgO4, and tungstate MgWO4. The synthesis efficiency was evaluated on the mixture weight magnitude losses, morphology, and relative weight of the obtained ceramic samples. Based on the analysis of the synthesis results and measuring the particle distribution spectra of the initial materials, the criteria for selecting the initial materials were established, and possible explanations for the correlation between synthesis efficiency and the initial materials morphology were proposed.

Achieving 17.46% Efficiency CsPbI2Br Perovskite Solar Cells via Multifunction Lead Chloride‐Modified ZnO Electron Transporting Layer

AbstractCsPbI2Br perovskite solar cells (PSCs) have garnered significant attention owing to their remarkable thermal stability and desirable bandgap. However, CsPbI2Br‐based devices still face critical challenges, particularly at the interfaces between the active layer and adjacent components. In this study, a multifunctional ZnO composition has developed as the electron transporting layer (ETL) for CsPbI2Br PSCs, enabling simultaneous efficient charge extraction and passivation of buried interface defects in CsPbI2Br. The nanocomposite, composed of PbCl2‐modified ZnO (PbCl2‐ZnO), facilitates the regulation of bandgap and conduction band to align the energy level of ETL and CsPbI2Br. Additionally, the residual PbCl2 at the buried interface of the perovskite incorporates into the perovskite lattice, reducing I defect and thus improving film quality. The improved energy level alignment at the ETL/CsPbI2Br interface and the suppressed I defect‐induced carrier nonradiative recombination result in a remarkable reduction in energy loss from 0.73 to 0.52 eV. Finally, the PbCl2‐ZnO hybrid nanocomposite ETL significantly enhances the efficiency of CsPbI2Br PSCs, increasing it from 14.15% to 17.46%, representing one of the highest reported power conversion efficiency (PCE) values for CsPbI2Br PSCs. These findings demonstrate the potential of PbCl2‐ZnO hybrid nanocomposite as an effective ETL for CsPbI2Br PSCs.

Galactomannan polysaccharide as a biotemplate for the synthesis of zinc oxide nanoparticles with photocatalytic, antimicrobial and anticancer applications

Biotemplates provide a facile, rapid, and environmentally benign route for synthesizing various nanostructured materials. Herein, Locust Bean Gum (LBG), a galactomannan polysaccharide, has been used as a biotemplate for synthesizing ZnO nanoparticles (NPs) for the first time. The composition, structure, morphology, and bandgap of ZnO were investigated by Energy Dispersive X-ray Spectroscopy (EDX), X-Ray Photoelectron Spectroscopy (XPS), X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and UV–vis spectroscopy. XRD data showed single-phase crystalline hexagonal NPs. FTIR spectra confirmed the presence of M-O bonding in the sample. At a concentration of 0.5 mg/mL the NPs can degrade Rhodamine B under sunlight, displaying excellent photocatalytic activity. These NPs exhibited antimicrobial activity in both Staphylococcus aureus and Bacillus subtilis. Significant cell death was observed at 500 μg/mL, 250 μg/mL, 125 μg/mL and 62.5 μg/mL of NP in breast cancer, ovarian cancer and lung cancer cell lines. Wound healing assay showed that the NPs significantly blocked the cell migration at a concentration as low as 62.5 μg/mL in all three cell lines. Further optimization of the nanostructure properties will make it a promising candidate in the field of nano-biotechnology and bioengineering owing to its wide range of potential applications.

Development of a novel flexible thin PWO(Er)/ZnO(Ag) nanocomposite for ionizing radiation sensing

Radiation dosimetry is an essential aspect of modern radiotherapy. Optically stimulated luminescence (OSL) dosimetry is a promising technique that uses materials to measure radiation doses. However, current OSL dosimeters are limited in their ability to provide comprehensive validation of spatial dose distributions, particularly in flexibility radiation sensitivity. In this regard, a novel flexible PWO(Er)/ZnO(Ag) nanocomposite sensor has been developed by a solvothermal procedure and its ionization radiation responses were investigated under UV, proton, laser 980 nm, and 241Am sources. The calculated alpha detection efficiency showed that the prepared PWO(Er)/ZnO(Ag) sensor is highly sensitive to alpha radiation (99.6 %) with good stability/repeatability and linear response. According to the Photo/Ionoluminescence study, the doped dual nanocomposite sample showed the strongest blue, green, and yellow emissions at room temperature compared with pure and single doped samples with an exciton lifetime of τ = 143.30 ±0.07 μs. The XRD, FTIR, Raman, and EDX results indicated that the prepared pure and doped nanocomposites have two-phase compositions of PWO and ZnO and related chemical compounds/elements in the nanocomposite structure. The morphologies of the PWO and PWO(Er) nanoparticles (NPs) were mostly cubic and heterogeneous with average particle sizes of 125 and 82 nm. ZnO and ZnO(Ag) had hexagonal, spherical, and rod-shaped particles with typical particle diameters of 130 and 90 nm, respectively. Our results indicate the prepared luminescent nanocomposites are transparent, flexible, highly stable, highly sensitive to ionizing radiation, and have the potential for practical use in optoelectronics and medical imaging in the future.

Structural, optical and electrical properties of ZnO–InN quaternary compound films

The ZnO–InN compound films were fabricated via both RF and DC sputtering by using indium and zinc metal target, where N2O and N2 gases were employed as the sputtering gas. The optical band gap was continuously tuned from 1.9 to 3.4 eV by precisely tailoring the chemical composition of the compound film. Both optical band gap and lattice spacing can be described by Vegard rule well. The carrier density can be adjusted up to 6.20 × 1020 cm−3 by varying the chemical composition of ZnO–InN compound. When the carrier density exceeds ∼1020 cm−3, the ZnO–InN compound films show the characteristics of degenerated semiconductor. Our experiments also reveal that the grain boundary scattering dominates carrier transport for ZnO–InN compound films with carrier density below 1020 cm−3.

ZnO nanocomposites supported by acid-activated kaolinite as photocatalysts for the enhanced photodegradation of an organic dye

Nanocomposite photocatalysts have attracted considerable attention for their enhanced photocatalytic ability compared to single metal oxide photocatalysts. The matrix in a nanocomposite plays a vital role in determining the efficiency of a photocatalyst. Acid-activated kaolinite (AAK) provides an excellent matrix owing to its higher surface area. In the present study, two nanocomposites were prepared with varying compositions of ZnO and acid-activated kaolinite (AAK) for use as photocatalysts. The ZnO/AAK nanocomposites were prepared in a wet chemical precipitation method and characterized using a range of techniques. The photocatalysts were then used for the photocatalytic degradation of MB in an aqueous solution under UV irradiation. The reaction parameters affecting the photocatalytic efficiency, such as the pH of the solution, initial concentration of dye, and catalyst dose, were optimized. The recyclability of the nanocomposites was also evaluated. ZnO was synthesized and dispersed over the AAK matrix. The particle size of ZnO in nanocomposites was ∼50 nm, and the optical bandgap of the nanocomposites was reduced significantly compared to single ZnO. Both AAK/ZnO nanocomposites exhibited high degradation efficiency. In particular, the ZK-30 nanocomposite, containing only 30 wt% ZnO, removed 98 % of MB from an aqueous solution. The recyclability test of the nanocomposites exhibited 80–99 % dye removal for up to three consecutive photocatalytic cycles.

Influence of Zinc Salt Concentration on Structured ZnO Composition and Morphology

AbstractIn the present work, Zinc oxide nanorods (ZnO NRs) and Simonkolleite (Zn5(OH)8Cl22H2O) nanodisks were successfully prepared hydrothermally using zinc chloride as a zinc source salt. The molarity of the zinc salt was varied to investigate its effect on the structure of the synthesized nanostructures. X‐ray diffraction (XRD), scanning electron microscopy (SEM), UV‐visible optical transmittance, and photoluminescence were used to characterize the synthesized nanostructures. These results suggest that the morphology of the synthesized nanostructures was significantly influenced by the molarity of zinc chloride. We inferred that increasing zinc salt molarity above 0.01 M leads to a pure simonkolleite nanodisks. In contrast, ZnO NRs were formed at low concentrations.

Green Synthesis of ZnO and V-Doped ZnO Nanoparticles Using Vinca rosea Plant Leaf for Biomedical Applications.

The present work focused on the synthesis of Vinca rosea leaf extract derived ZnO and vanadium-doped ZnO nanoparticles (V-ZnO NPs). The chemical composition, structural, and morphology of ZnO and vanadium-doped ZnO NPs were examined by FTIR, XRD, and SEM-EDX. The FTIR confirmed the presence of functional groups corresponding to ZnO and vanadium-doped ZnO NPs. SEM-EDX clearly indicated the morphology of synthesised NPs; the hexagonal crystal of NPs was confirmed from XRD. In addition, the cytotoxic effect of ZnO and V-ZnO NPs was estimated against the breast cancer (MCF-7) cell line. From the assay, Vinca rosea (V. rosea) capped ZnO NPs have shown improved cytotoxic activity than that of Vinca rosea capped V-ZnO NPs. ZnO and vanadium-doped ZnO NPs showed the strongest antibacterial activity against Enterococcus, Escherichia coli, Candidaalbicans, and Aspergillus niger. The α-amylase inhibition assays demonstrated antidiabetic activity of synthesised NPs. From the assay test, results obtained Vinca rosea capped ZnO nanoparticles prepared using the green approach showed high effective antioxidant, antidiabetic activity, and anticancer activity than vanadium-doped ZnO NPs.

PANI-ZnO clad modified multimode optical fiber pH sensor based on EWA

In the present investigation, an intrinsic intensity modulated optical fiber pH sensor is developed and experimentally tested at room temperature. To fabricate the sensor probe, original cladding of multimode fiber was replaced by a pH-sensitive polyaniline-zinc oxide (PANI-ZnO) nanocomposite matrix whose absorbance property and refractive index (RI) are pH dependent. The synthesized PANI, ZnO, and incorporation of ZnO into PANI was confirmed and analyzed by some characterization techniques. It was observed that the ZnO composition into PANI not only enhances the materials's optical activity, porosity and hence sensitivity of the sensor but also boosts the mechanical strength of the coating layer over silica surface. Moreover, high index ZnO material is used to enhance the evanescent field towards the sensing region, which can help in better interaction of light from the outer medium. The pH sensing principle depends upon evanescent wave absorption (EWA) due to swelling/shrinkage of PANI and hence modification in volume and RI of the layer leads to change in transmitted optical power. The average sensitivity of proposed sensor was found to be 2.46 μW/pH for a wide pH range of 2–10 unit. The sensor also possesses excellent stability, fast response time, low hysteresis, good repeatability and durability characteristics. Results suggest that this sensor can be productively utilized in biomedical and chemical sensing applications.

Solvothermal synthesis of ZnO with controllable morphology

ZnO structures were prepared by a two-step procedure. Firstly ZnO were synthesized by hydrothermal method with methanol as solvent and then annealed in air. The structure and morphology of the samples were analyzed by XRD and SEM. The chemical composition of the samples was determined by XPS. The optical properties were analyzed by fluorescence spectroscopy. The results show that the reaction time has an important influence on the morphology, chemical composition and optical properties of ZnO.