Zinc Oxide Research Articles

Autonomous and Ultrasensitive Low-Power Metal Oxide Nanofiber Gas Sensor for Source Tracking and Localization.

Current toxic gas detection methods in industrial and environmental settings are limited by their reliance on manual monitoring and stationary sensors. Here, we present an autonomous mobile gas sensing system offering real-time monitoring and precise gas source localization without the need for human intervention. Room-temperature gas sensors based on high specific surface area indium gallium zinc oxide nanofibers (IGZO NFs) are developed, which exhibit low power consumption (∼0.5 mW), exceptional sensitivity (∼1290% ppb-1), and a low detection limit of 20 ppb for toxic NO2. When integrated into an autonomous mobile platform and supported by adaptive biologically inspired algorithms, the system exhibits a source localization efficiency of ∼1.5 m min-1, offering a remote, scalable, and efficient solution for detecting and localizing toxic gas leaks.

Green synthesis of flower-like ZnO nanoparticles mediated by paulownia tomentosa: characterization and drug delivery performance

This study reports an eco-friendly synthesis of hierarchically structured zinc oxide nanoparticles using Paulownia tomentosa leaf extract as a bio-template. The synthesized nanoparticles displayed a distinctive flower-like morphology developed through a threestage assembly process, confirmed by time-dependent morphological analysis. BET analysis revealed a mesoporous structure with type IV isotherms and H3 hysteresis loops. Spectroscopic characterization confirmed the wurtzite crystal structure with characteristic Raman modes at 438 cm⁻¹ (E2-high), 380 cm⁻¹ (A1-TO), and 583 cm⁻¹ (E1-LO). Surface modification with PEG-4000 enhanced the nanoparticles' performance as drug carriers, demonstrating Korsmeyer-Peppas model release kinetics (R² = 0.992) with a release exponent of 0.68. The nanostructures showed 2.3-fold higher drug loading capacity compared to conventional spherical ZnO particles. Biological evaluation revealed significant antimicrobial efficacy with inhibition zones of 28 mm against S. aureus and 24 mm against E. coli at 100 µg/mL concentration, while demonstrating selective cytotoxicity against MCF-7 breast cancer cells with minimal effect on normal breast epithelial cells.

Piezoelectric and Photoconductive Zinc Oxide-Wood Hybrids Obtained by Atomic Layer Deposition.

The development of sustainable functional wood-based materials for advanced photonic, optical, and energy-harvesting applications is a topic of great priority and scientific interest. Owing to its inherent piezoactivity and photoconductivity, zinc oxide (ZnO) can be of help for all these applications. While previously used for wood-based piezoelectric nanogenerators, its use for enabling wood with photoconductive properties has not yet been demonstrated. Here, we introduce an innovative method to produce ZnO-wood hybrids based on atomic layer deposition (ALD), a technique so far underrepresented in the field of wood functionalization. By a studied combination of ALD, customized sample geometry, structure-retaining delignification, and careful selection of the drying method, we obtained a homogeneous functionalization of a bulk wood scaffold with layers of nanocrystalline ZnO. This approach allowed us to achieve control over the homogeneity, distribution, and coating thickness of the oxide layer. The micro- and nanostructure of the resulting hybrids were investigated by electron microscopy as well as by X-ray diffraction and scattering. The ZnO-wood hybrids show an anisotropic piezoelectric response due to the natural structure of the wood. Moreover, we demonstrate the use of ZnO-functionalized wood for the fabrication of bulk (photo)conductive wood. Upon irradiation with UV light, a significant decrease in resistivity is observed, which increases again upon removal of UV light. Finally, we used the hybrids to fabricate a ZnO-wood replica by thermal removal of the cellulose scaffold. This treatment leaves behind a detailed inorganic wood replica down to the smallest open accessible features such as micrometer-sized wood pits.

New Perspectives on Titanium Dioxide and Zinc Oxide as Inorganic UV Filters: Advances, Safety, Challenges, and Environmental Considerations

Exposure to ultraviolet (UV) radiation is a primary risk factor for various skin disorders, including erythema, sunburn, and skin cancer. Sunscreens containing UV filters, categorized as organic or inorganic, are widely utilized to mitigate these effects. Among inorganic UV filters, titanium dioxide (TiO2) and zinc oxide (ZnO) are prominently used due to their favorable safety and achievable broad-spectrum protection profiles. This review focuses on the properties, safety, and efficacy of TiO2 and ZnO in sunscreens, emphasizing their mechanisms of action, photostability, and impacts on human health and the environment. Key factors influencing their performance include particle size, surface coatings, and formulation pH. Despite recognized advantages, concerns about toxicity—particularly related to nanoparticle penetration and reactive oxygen species generation—highlight the need for robust safety assessments. Additionally, the environmental impacts of inorganic UV filters, including bioaccumulation and effects on aquatic ecosystems, warrant consideration. Advances in nanoparticle synthesis, bioactive compound integration, and environmentally friendly formulations offer pathways to enhance sunscreen efficacy and safety, providing opportunities for innovation in photoprotection.

Zinc Oxide Nanowire‐Enhanced Interlocking Interfaces in Mechanically Robust Basalt Fiber/Epoxy Lamellar Composites

ABSTRACTThe contradiction between the widespread application of basalt fibers (BFs) and their poor interfacial interaction with polymers has become an urgent issue for the preparation of BF/thermosetting polymer composites. In this study, zinc oxide (ZnO) nanofibers were successfully grown on the surface of BFs through a surface modification process involving polydopamine (PDA) coating, followed by a two‐step hydrothermal method to create an interfacial interlocking structure. As a result, the interfacial interaction between the modified BFs and epoxy resin was significantly enhanced, as evidenced by the increase in interfacial shear strength from 13.3 to 22.4 MPa, greatly improving the mechanical properties of the resulting composite. The impact toughness and flexural strength of the modified composites increased from 46.4 kJ/m2 and 278.4 MPa to 59.6 kJ/m2 and 347.5 MPa, respectively. This not only addresses the issue of weak interfacial interaction between BFs and polymers to expand the application potential of BFs, but also provides an effective strategy for the other inorganic fibers to enhance the interfacial interaction with polymer.

Exploration of the Effects of Nanoscale Surface Morphology Variations on Onset of Bubble Nucleation in Water Droplets Impinging and Boiling on Nanostructured Surfaces

Abstract Nanostructured hydrophilic surfaces can enhance boiling processes due to the liquid wicking effect of the small surface structures. However, consistently uniform nanoscale interstitial spaces would require high superheat to initiate heterogeneous nucleation in the available small cavity spaces. Experimental studies indicate that surfaces of this type initiate onset of nucleate boiling at relatively low superheat levels, implying that significantly larger interstitial spaces exist, apparently as a consequence of the fabrication process. To explore the correlation between nanostructured surface morphology variations and variation of nucleation behavior with superheat, in this study, a zinc oxide nanostructured coating was fabricated on various copper substrates for wetting and droplet vaporization heat transfer experiments and morphology analysis. Our experiments determined the variation of mean droplet heat flux with superheat, and high-speed videos documented how nucleation features varied with superheat. Image analysis of the electron microscopy images was used to assess the variability of pore size and surface complexity (entropy) over the surface. Our data demonstrates the correlation between surface morphology feature distributions and the variation of nucleate boiling active site density with superheat. Specifically, our results indicate that increased availability of larger-scale surface irregularities with low surface entropy corresponds to enhanced probability of nucleation onset and an increase in active nucleation site density as superheat increases. This information can help guide development of enhanced boiling surfaces by providing insight into the nanosurface feature density distributions that enhance nucleation onset while also providing enhanced wicking and low contact angle over most of the surface.

Nano Zinc Oxide Enhances Corn Growth and Nutrient Uptake: Comparison between Soil Drench and Seed Coating Applications in Alkaline Sandy Soils

Nano Zinc Oxide Enhances Corn Growth and Nutrient Uptake: Comparison between Soil Drench and Seed Coating Applications in Alkaline Sandy Soils

Performance Enhancement of IGZO Thin-Film Transistors via Ultrathin HfO2 and the Implementation of Logic Device Functionality

Abstract The enhancement of mobility has always been a research focus in the field of thin-film transistors (TFTs). In this paper, we report a method of using ultrathin HfO2 to improve the electrical performance of indium gallium zinc oxide (IGZO) TFTs. HfO2 can not only repairs the surface morphology of the active layer but also enhances the carrier concentration. When the thickness of the HfO2 film was 3 nm, the mobility of the device was doubled (14.9 cm2V-1s-1 → 29.6 cm2V-1s-1), and the device exhibited excellent logic device performance. This paper provides a simple and effective method to enhance the electrical performance of IGZO TFTs, offering new ideas and experimental foundation for the research of high-performance metal oxide (MO) TFTs.

Dietary fatty acids promote gut health in weaned piglets by regulating gut microbiota and immune function

BackgroundPost-weaning diarrhea in piglets is a common challenge that adversely impacts growth performance and increases mortality, leading to severe economic losses. Medium-chain fatty acids (MCFA) and short-chain fatty acids (SCFA) are frequently used as feed additives due to their bioactive properties. This study evaluated the effects of two different blends of MCFA and SCFA (VSM and VS + VM) as alternatives to zinc oxide (ZnO) on growth performance, nutrient digestibility, oxidative stress, inflammatory, and gut microbiota composition in weaned piglets.Methods and resultsA total of 108 piglets (8.22 ± 0.51 kg) were randomly assigned to three treatments: control (CON, basal diet + ZnO), VSM (basal diet + higher MCFA and lower SCFA content) and VS + VM (basal diet + higher SCFA and lower MCFA content). Results indicated that Both VSM and VS + VM, can replace ZnO to relieve diarrhea of weaned piglets as evidenced by increased average daily gain (ADG) and decreased feed to gain ratio (F/G) in 1–15 days, with no difference in final body weight compared to the CON group. Additionally, dietary MCFA and SCFA supplementation improves anti-oxidative and anti-inflammatory capacity by decreased of malondialdehyde (MDA) activity, and inhibited proinflammatory cytokine tumor necrosis factor α (TNF-α) and interleukin (IL-1β, IL-17A) secretion. Further study showed that the protective effect of MCFA and SCFA were associated with restoring gut barrier, upregulating abundances of Lactobacillus and Roseburia of piglets.InterpretationCollectively, the combination of MCFA and SCFA alleviated oxidative stress, modulated inflammation, and supported gut barrier function in weaned piglets, offering a promising alternative to ZnO, with VSM showing superior effects.

Advanced Nanoenabled Microalgae Systems: Integrating Oxidative Stress-Induced Metabolic Reprogramming and Enhanced Lipid Biosynthesis for Next-Generation Biofuel Production.

The growing demand for renewable energy has positioned microalgae, such as Chlorella vulgaris, as a promising feedstock for sustainable biofuel production. Leveraging nanotechnology, this study explores the multifaceted impacts of zinc oxide (ZnO) nanoparticles (NPs) on C. vulgaris, focusing on lipid biosynthesis, oxidative stress, biomass productivity, and photosynthetic pigment retention. The morphology of NPs and algae and their interactions were extensively studied using scanning electron microscopy (SEM), confocal microscopy, energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The ZnO NP-enabled microalgae system enhanced lipid accumulation to as high as 48% at 50 mg/L. Biomass production and pigment content remained stable within the applied dose of NPs (20-50 mg/L), highlighting the resilience of C. vulgaris under NP exposure. However, at 100 mg/L, photosynthetic efficiency was disrupted, pigment content was reduced, and lipid yield declined to 30%. The enzymatic activity of catalase (CAT) revealed significant upregulation at higher ZnO NP concentrations, further corroborating the stress-induced metabolic shifts. This study also introduced a model for the Biofuel Suitability Score (BSS), which integrates lipid content, biomass productivity, oxidative stress levels, and pigment retention to identify the optimal conditions for biofuel production. The BSS peaked at moderate ZnO NP concentrations (30-50 mg/L), indicating a balance between lipid biosynthesis and cellular integrity. Beyond this threshold, oxidative damage compromises the biofuel potential, emphasizing the critical need for precise control of NP exposure. These findings highlight the potential of ZnO NPs to induce lipid accumulation through targeted stress modulation while maintaining biomass quality, advancing the application of nanotechnology in sustainable bioenergy systems. This study provides a scalable framework for integrating nanotechnology into renewable energy.

Flexible Tunable-Plasticity Synaptic Transistors for Mimicking Dynamic Cognition and Reservoir Computing.

Inspired by biological systems, neuromorphic computing can process extensive data and complex tasks more efficiently than traditional architectures. Artificial synaptic devices, serving as fundamental components in neuromorphic computing, needto closely mimic synaptic characteristics and construct neural network computing systems. However, most existing multifunctional synapse devices are structurally complex and lack tunability, making them unsuitable for building smarter computing systems. In this work, a flexible tunable-plasticity synaptic transistor (TST) is realized with memory modulation and neuromorphic computing capabilities by using indium gallium zinc oxide as channel and a hybrid layer of polyimide and Al2O3 as dielectric. The TST exhibits a novel transition from short-term plasticity to long-term one by adjusting stimulus amplitude, mirroring dynamic human memory and forgetting behaviors across various scenarios. A neural network system with low non-linearity and a wide range of conductance variations is constructed, and it demonstrates a 94.1% recognition rate on classical datasets. A reservoir computing system for 4-bit coding is also developed, which significantly reduces computational complexity and network size without sacrificing recognition accuracy. The devices and the system work as the foundation of more intelligent and more efficient computing systems.

In situ n-doped nanocrystalline electron-injection-layer for general-lighting quantum-dot LEDs

Quantum-dot optoelectronics, pivotal for lighting, lasing and photovoltaics, rely on nanocrystalline oxide electron-injection layer. Here, we discover that the prevalent surface magnesium-modified zinc oxide electron-injection layer possesses poor n-type attributes, leading to the suboptimal and encapsulation-resin-sensitive performance of quantum-dot light-emitting diodes. A heavily n-doped nanocrystalline electron-injection layer—exhibiting ohmic transport with 1000 times higher electron conductivity and improved hole blockage—is developed via a simple reductive treatment. The resulting sub-bandgap-driven quantum-dot light-emitting diodes exhibit optimal efficiency and extraordinarily-high brightness, surpassing current benchmarks by at least 2.6-fold, and reaching levels suitable for quantum-dot laser diodes with only modest bias. This breakthrough further empowers white-lighting quantum-dot light-emitting diodes to exceed the 2035 U.S. Department of Energy’s targets for general lighting, which currently accounts for ~15% of global electricity consumption. Our work opens a door for understanding and optimizing carrier transport in nanocrystalline semiconductors shared by various types of solution-processed optoelectronic devices.

Antioxidant and antimicrobial properties of zinc oxide nanoparticles green synthesized with Bunium persicum essential oil

This study evaluated the antioxidant and antibacterial properties of zinc oxide nanoparticles containing Bunium persicum (Boiss.) B. Fedtsch. essential oil synthesized using a green method. The analyses were conducted with three replications using a completely randomized methodology. The means were compared using Duncan’s multiple range test at a significance level of 5% using SPSS version 22 statistical software. In the microbial test, the antimicrobial property of zinc oxide nanoparticles with cumin essential oil was significantly higher than that of B. persicum (Boiss.) B. Fedtsch. essential oil in both disc diffusion and microbroth dilution methods (p < 0.05). In addition, zinc oxide nanoparticles with B. persicum (Boiss.) B. Fedtsch. essential oil had the most significant effect on Candida Albicans yeast, then on the gram-positive Staphylococcus aureus bacteria, and finally on the gram-negative Escherichia coli bacteria. Zinc oxide nanoparticles combined with B. persicum (Boiss.) B. Fedtsch. essential oil showed a better result than B. persicum (Boiss.) B. Fedtsch. essential oil in measuring the amount of total phenolic compounds (p < 0.05). In the test of particle size and dispersion index, there was a significant difference in the samples (p < 0.05). The lowest particle size and particle size dispersion index were related to the sample of zinc oxide nanoparticles with B. persicum (Boiss.) B. Fedtsch. essential oil.

A Facile Synthesis Approach for Iron-Doped Zinc Oxide Nanoparticles with Enhanced Antibacterial Properties

Bacterial resistance to commonly administered drugs has necessitated the need for alternative drugs for effective treatment. In this study, the synthesis, characterization, and antibacterial activity of iron-doped zinc oxide nanoparticles (Fe-ZnO Nps) were investigated. The synthesized nanoparticles (Nps) were characterized using Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Spectroscopy (EDX) and Transmission Electron Microscopy (TEM) methods of analysis. The synthesized Nps were tested against ten Clinical bacteria, which were both Gram-positive and Gram-negative (Micrococcus luteus, Bacillus subtilis, Escherichia coli, Enterobacter agglumerans, Klebsiella pneumoniae, Acinetobacter baumannii, Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa and Corynebacterium bovis) using the agar diffusion method. SEM/EDX images showed the spherical nature and the elemental composition of the nanoparticles, and the TEM images showed the morphology and the nanoparticles' size distribution. The presence of all the expected elements was an indication of the successful synthesis of the nanoparticles. Moreover, the SEM image of the synthesized nanoparticles showed that the nanoparticles were not uniformly distributed and that the nanoparticles were of different sizes. Iron-doped zinc oxide nanoparticles (Fe-ZnO Nps) exhibited excellent and significant antimicrobial activity against all the bacteria (inhibitory zones ranging from 29.00 - 32.00 mm). The result from this study revealed that all the organisms were susceptible to the synthesized Fe-ZnO Nps. The obtained result is a clear indication of the potential applications of the Fe-doped ZnO Nps to combat the challenge of bacterial resistance.

Elevated temperature and pressure performance of water based drilling mud with green synthesized zinc oxide nanoparticles and biodegradable polymer

Water-based mud (WBM) faces challenges in high-temperature, high-pressure (HTHP) conditions due to fluid loss and property degradation. Enhancing eco-friendly drilling fluids with optimal rheology is crucial for sustainable, cost-effective, and environmentally safe drilling operations. This study formulated a WBM using green-synthesized zinc oxide (ZnO) nanoparticles (NPs, ~ 45 nm) and tragacanth gum (TG), a biodegradable natural polymer. The synthesized ZnO NPs were comprehensively characterized using energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA/DTG) to determine their structural, morphological, and chemical properties. Rheological properties, including flow behavior index (n), consistency index (K), plastic viscosity (PV), and yield point (YP), were analyzed at 25, 50, and 75 °C using the Bingham-plastic and Power-law models. The accuracy of the model was validated using Analysis of Variance (ANOVA), which assessed the significance of the results. Additionally, Design Expert software was utilized to optimize the concentrations of TG and ZnO for elevated temperature applications. Moreover, the response surface methodology (RSM) results were evaluated by reporting the R2 and accuracy metrics, confirming the strong correlation between predicted and actual values, which demonstrates the model’s robustness. Three optimal samples underwent HTHP filtration tests at 120 °C and 500 psi. The ideal formulation of 750 ppm TG and 0.25 wt% ZnO NPs improved PV by 27.84%, YP by 43.16%, reduced fluid loss by 54.16%, and mud cake thickness by 25%. The optimized sample showed superior performance, with a ‘K’ of 56.12 cp and a ‘n’ of 0.2272, ensuring effectiveness under HTHP conditions. This sustainable formulation reduced environmental contamination risks and drilling fluid consumption while enhancing operational efficiency.

Green synthesis of zinc oxide nanoparticles for the control of insects that damage historical and art pieces made of wood

Abstract Wood is one of the most versatile materials, including religious symbols and carved works of art. However, it is a material that is vulnerable to biodeterioration by insects, fungi, and other organisms. Biodeterioration by xylophagous insects is one of the main problems for the conservation of wooden objects; however, control methods are focused on insecticides which can be harmful and toxic to humans and the environment. In this work, the use of zinc oxide nanoparticles obtained by green synthesis with an aqueous extract of agro-industrial waste such as orange peels and zinc nitrate was proposed. It porposes an alternative to the use of toxic substances against the attack of Bostrichidae xylophagous insects of the genus Prostephanus on wood. The results obtained show that the chemical composition of orange peels extract is a good alternative for the green synthesis of zinc oxide nanoparticles. Information obtained from SEM, SEM-EDX and TEM analysis of the material provided agglomerated structural morphology, zinc oxide composition and particle size on the nanometric scale. Preliminary studies of the biocidal activity of zinc oxide nanoparticles alone and in ethanol suspension (1, 3, 5 %) demonstrated the effective protection of broadleaf wood blocks against the attack of the xylophagous insect Brostrichidae of the Prostephanus genus. The biocidal activity increased up to 75 % when zinc oxide nanoparticles were applied directly rather than in ethanolic suspension. Furthermore, the nanoparticles increased water absorption capacity played an important role in removing local moisture from the cavity, which is vital for the insect’s development at the larval stage.

Photothermal Superhydrophobic Zinc Oxide Cotton Fabric Based on an Impregnation Method.

Superhydrophobic materials have applications such as oil-water separation, antifouling, and antibacterial properties. At present, most of the manufacturing process of superhydrophobic coatings not only is costly but also causes pollution to the environment, which is not in line with the concept of green and sustainable development. In this work, we have prepared a superhydrophobic coating using green and environmentally friendly chitosan, nanozinc oxide, γ-aminopropyl triethoxysilane (KH550), and stearic acid. The prepared cotton fabric showed remarkable superhydrophobic properties. Under simulated sunlight, the surface temperature of the superhydrophobic cotton fabric can increase to 50 °C. The superhydrophobic surface sustained its superhydrophobic property after at least 80 tape peeling tests, 50 occurrences of sandpaper friction, 3.5 h of washing, and 24 h of high-temperature heat treatment. Besides, the coating can be utilized for oil-water separation and is reusable. The oil-water separation effectiveness of the coating reaches more than 95%. Therefore, this inexpensive and ecofriendly nanozinc oxide/chitosan-based superhydrophobic coating has remarkable application potential.

Photocatalytic oxidation of antibiotic residue and organic dye pollutant using noble metal-doped ZnO: Reducing environmental and health risks

Water pollution associated with antibiotic residues and colored organic pollutants leads to various potential risks to human health and the environment. This work develops an economical method that is suitable for removing both antibiotic residues and colored organic pollutants from water. The oxidation process based on a noble metal (Ag)-doped zinc oxide photocatalyst (Ag-ZnO) was selected as a potential strategy for investigation. Besides, tetracycline antibiotic residues (A-Tc) and methylene blue-colored organic pollutants (D-Mb) were selected as target contaminants. With light assistance, Ag-ZnO showed significantly improved degradation efficiency for A-Tc and D-Mb at 90.6 and 97.3%, respectively. The advantages of Ag-ZnO are also confirmed by the faster degradation rate constants, which are more than twice as fast as those of the undoped sample. The mineralization process shows that 93.5% and 98.7% of organic carbon were removed from the A-Tc and D-Mb solutions, respectively. The result suggests that antibiotic residues and colored organic pollutants are being converted into inorganic substances. In addition, the benefits of using Ag-ZnO to enhance human health safety, reduce the negative effects on the environment, and decrease treatment costs are discussed.

Development of an Improved Zinc Oxide Thin Film Transistor for Next-Generation Smartphone Display Technologies

Development of an Improved Zinc Oxide Thin Film Transistor for Next-Generation Smartphone Display Technologies

Electronic Nose Based on a Multi‐Thin Film Transistor Sensor Array Structure for Detecting Odorants with High Selectivity

Electrical noses that mimic the human olfactory system have been developed to detect odors or flavors. Unfortunately, little research on sensing reactions to various odors like a human nose can be found in the literature. Herein, an electronic nose is proposed using a multi‐thin film transistor (TFT) sensor array with various polymer selectors and multi‐output signal processing to detect various odorants with high selectivity. Through the combination of multi‐output produced by eight polymer variables based on indium gallium zinc oxide (IGZO) TFTs, a specific radar pattern and its selectivity are generated for the eight different odor substances. Eight multi‐output signal processing reduced the correlation coefficient of similarity from 77.9% to 45% relative to the case of four multi‐output processing. Because the polymers have different functional groups, polymers showed specific reactions to various odorants, like the human's system, and multi‐output analysis could distinguish various odors, even if polymers did not show single selectivity to a specific odor. And the sensitivity improved when compared to two‐terminal structures by using TFTs based on IGZO. The advantage is that it can classify multiple odors with good selectivity and sensitivity. This sensor and signal processing concept can be applied to E‐nose systems capable of odor monitoring.