Search Results (19)

We report a novel approach to fabricating high-performance and robust quantum dot light-emitting diodes (QLEDs) utilizing sputtered SnO₂ thin films as the electron transport layer (ETL). While conventional solution-processed ZnMgO NP ETLs face limitations in mass production, the sputtering process offers advantages for uniform and reproducible thin film deposition. Herein, the structural, optical, and electrical properties of SnO₂ thin films were optimized by controlling the Ar/O₂ ratio and substrate heating temperature during sputtering. SnO₂ thin films with O₂ gas improve charge balancing in QLEDs by lowering the conduction band minimum. Furthermore, it was observed that oxygen vacancies in SnO₂ function as exciton quenching sites, which directly impacts the long-term stability of the device. QLEDs fabricated under optimal conditions (Ar/O₂ = 35:5, 200 °C heating) achieved a peak luminance of 99,212 cd/m² and a current efficiency of 21.17 cd/A with excellent device stability. The findings suggest that sputtered SnO₂ ETLs are a highly promising technology for the commercial production of QLEDs. Full article

Fruit and vegetable production is often impacted by microbial pathogens that compromise the quality of produce and lead to significant economic losses at the postharvest stages. Due to their efficacy, agrochemicals are widely applied in disease management; nevertheless, this practice has led to the appearance of microbial strains resistant to these types of agrochemicals. Additionally, there is growing concern among consumers about the presence of these chemical residues in fruits and the negative impacts they cause on multiple ecosystems. In response, there is a growing need for safe, effective, green, and sustainable disease control technologies. Bionanocomposites, with their unique ability to combine nanomaterials and biopolymers that have attractive properties, represents a promising alternative for postharvest disease control. These technologies allow for the development of functional coatings and films with antimicrobial, antioxidant, and barrier properties, which are critical for extending shelf life and preserving fruit quality. Recent advances have demonstrated that integrating nanoparticles, such as ZnO, TiO₂, Ag, and chitosan-based nanosystems, into biopolymeric matrices, like alginate, pectin, starch, or cellulose, can enhance mechanical strength, regulate gas exchange, and control the release of active agents. This review presents systematized information that is focused on the creation of coatings and films based on bionanocomposites for the management of disease in fruits and vegetables. It also discusses the use of diverse biopolymers and nanomaterials and their impact on the quality and shelf life of fruits and vegetables. Full article

High-k metal oxides are gradually replacing the traditional SiO₂ dielectric layer in the new generation of electronic devices. In this paper, we report the production of five-element high entropy metal oxides (HEMOs) dielectric films by solution method and analyzed the role of each metal oxide in the system by characterizing the film properties. On this basis, we found optimal combination of (AlGaTiYZr)O_x with the best dielectric properties, exhibiting a low leakage current of 1.2 × 10⁻⁸ A/cm² @1 MV/cm and a high dielectric constant, while the film’s visible transmittance is more than 90%. Based on the results of factor analysis, we increased the dielectric constant up to 52.74 by increasing the proportion of TiO₂ in the HEMOs and maintained a large optical bandgap (>5 eV). We prepared thin film transistors (TFTs) based on an (AlGaTiYZr)O_x dielectric layer and an InGaZnO_x (IGZO) active layer, and the devices exhibit a mobility of 18.2 cm²/Vs, a threshold voltage (V_th) of −0.203 V, and an subthreshold swing (SS) of 0.288 V/dec, along with a minimal hysteresis, which suggests a good prospect of applying HEMOs to TFTs. It can be seen that the HEMOs dielectric films prepared based on the solution method can combine the advantages of various high-k dielectrics to obtain better film properties. Moreover, HEMOs dielectric films have the advantages of simple processing, low-temperature preparation, and low cost, which are expected to be widely used as dielectric layers in new flexible, transparent, and high-performance electronic devices in the future. Full article

The escalating environmental concerns associated with conventional plastic packaging have accelerated the development of sustainable alternatives, making food packaging a focus area for innovation. Bioplastics, particularly polyhydroxyalkanoates (PHAs), have emerged as potential candidates due to their biobased origin, biodegradability, and biocompatibility. PHAs stand out for their good mechanical and medium gas permeability properties, making them promising materials for food packaging applications. In parallel, zinc oxide (ZnO) nanoparticles (NPs) have gained attention for their antimicrobial properties and ability to enhance the mechanical and barrier properties of (bio)polymers. This review aims to provide a comprehensive introduction to the research on PHA/ZnO nanocomposites. It starts with the importance and current challenges of food packaging, followed by a discussion on the opportunities of bioplastics and PHAs. Next, the synthesis, properties, and application areas of ZnO NPs are discussed to introduce their potential use in (bio)plastic food packaging. Early research on PHA/ZnO nanocomposites has focused on solvent-assisted production methods, whereas novel technologies can offer additional possibilities with regard to industrial upscaling, safer or cheaper processing, or more specific incorporation of ZnO NPs in the matrix or on the surface of PHA films or fibers. Here, the use of solvent casting, melt processing, electrospinning, centrifugal fiber spinning, miniemulsion encapsulation, and ultrasonic spray coating to produce PHA/ZnO nanocomposites is explained. Finally, an overview is given of the reported effects of ZnO NP incorporation on thermal, mechanical, gas barrier, UV barrier, and antimicrobial properties in ZnO nanocomposites based on poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). We conclude that the functionality of PHA materials can be improved by optimizing the ZnO incorporation process and the complex interplay between intrinsic ZnO NP properties, dispersion quality, matrix–filler interactions, and crystallinity. Further research regarding the antimicrobial efficiency and potential migration of ZnO NPs in food (simulants) and the End-of-Life will determine the market potential of PHA/ZnO nanocomposites as active packaging material. Full article

Finishing coatings in the wood-based composites industry not only influence the final appearance of the product but also serve to protect against fungi and molds and reduce the release of harmful substances, particularly formaldehyde and volatile organic compounds (VOCs). Carbon-rich materials, such as those derived from birch bark extraction, specifically suberin acids, can fulfill this role. Previous research has demonstrated that adding suberin acid residues (SAR) at 20% and 50% by weight significantly enhances the gas barrier properties of surface-finishing materials based on poly(lactide) (PLA) and polycaprolactone (PCL), particularly in terms of total VOC (TVOC) and formaldehyde emissions. This study aims to explore whether these properties can be further improved through the incorporation of nano-zinc oxide (nano-ZnO). Previous research has shown that these nanoparticles possess strong resistance to biological factors and can positively affect the characteristics of nanofilms applied as surface protection. The study employed PLA and PCL finishing layers blended with SAR powder at 10% w/w and included 2% and 4% nano-zinc oxide nanoparticles. The resulting blends were milled to create a powder, which was subsequently pressed into 1 mm-thick films. These films were then applied to raw particleboard surfaces. TVOC and formaldehyde emission tests were conducted. Additionally, the fungal resistance of the coated surfaces was assessed. The results showed that PLA/SAR and PCL/SAR composites with the addition of nano-zinc oxide nanoparticles exhibited significantly improved barrier properties, offering a promising avenue for developing biodegradable, formaldehyde-free coatings with enhanced features in the furniture industry. Furthermore, by utilizing SAR as a post-extraction residue, this project aligns perfectly with the concept of upcycling. Full article

In this paper, the study is supported by design, FEA simulation, and practical RF measurements on fabricated single-port-cavity-based acoustic resonator for gas sensing applications. In the FEA simulation, frequency domain analysis was performed to enhance the performance of the acoustic resonator. The structural and surface morphologies of the deposited ZnO as a piezoelectric layer have been studied using XRD and AFM. The XRD pattern of deposited bulk ZnO film indicates the perfect single crystalline nature of the film with dominant phase (002) at 2θ = 34.58°. The AFM micrograph indicates that deposited piezoelectric film has a very smooth surface and small grain size. In the fabrication process, use of bulk micro machined oxide (SiO₂) for the production of a thin membrane as a support layer is adopted. A vector network analyzer (Model MS2028C, Anritsu) was used to measure the radio frequency response of the resonators from 1 GHz to 2.5 GHz. As a result, we have successfully fabricated an acoustic resonator operating at 1.84 GHz with a quality factor Q of 214 and an effective electromechanical coupling coefficient of 10.57%. Full article

5A06 aluminum alloy bar was brazed by temperature gradient transient liquid phase diffusion welding (TG-TLP). The effects of brazing temperature on the microstructure and the tensile strength of the brazing joints were investigated. Three typical brazing filler alloys (1^# Al-20Cu-6Si-2Ni, 2^# Al-10Cu-10Si-3Mg-1Ga, and 3^# Al-6Cu-10Si-2Mg-10Zn) were prepared by smelting, and TG-TLP diffusion bonding was carried out at different brazing temperatures (550 °C~590 °C). The results show that with the increase in brazing temperature, the oxide films at the brazing junction are easier to be broken and dispersed, but the oxidation extent will also increase. The oxidation products enriched were mainly Al₂O₃ and SiO₂ at the brazing junction. There are different optimal brazing temperatures corresponding to the different filler alloys. For 1^#, the optimal temperature is 570 °C; for 2^# is 580 °C; for 3^# is 580 °C. For 1^# brazing joints, the maximum tensile strength was 113 MPa, and for 2^# was 122.4 MPa. Under the experimental conditions of this study, the maximum tensile strength of the TG-TLP joint is 147.4 MPa of 3^# brazing sample (at 580 °C), which has increased by 30% and 20% compared to 1^# and 2^# respectively. The nickel-rich phase at the interface (of 1^# brazing filler) could form a brittle fracture, which was unfavorable for interface bonding. For TG-TLP brazing of 5A06, the filler alloy with high Al:Cu ratio (12:1 wt.%) needs a sufficient temperature gradient to exert the film-breaking effect, while the filler alloy with low Al:Cu ratio (3.6:1 wt.%) needs to accurately control its brazing temperature to avoid excessive oxidation. There are many research gaps in the influence of brazing material composition and brazing temperature on the microstructure and mechanical properties of 5A06 aluminum alloy TG-TLP joints. The research results can provide a theoretical basis for formulating the TG-TLP brazing specification of 5A06 aluminum alloy. Full article

Chemical sensors based on metal oxides (MOx) are one of the most promising gas sensing devices due to their high sensitivity to numerous gases, fast response, miniaturization, and simple production. The detection principle of these sensors is a conductivity change of the MOx-sensing material due to the chemical reactions of gases with surface molecules. Cross sensitivities and interference to humidity, however, are still significant drawbacks of these sensors. The functionalization of MOx-sensing films with catalytic nanoparticles (NP) is a highly promising technology for optimizing sensor performance. The huge variety of potential MOx–NP combinations requires efficient screening technologies to find proper hybrid material mixtures which enable the controlled adjustment of the sensor response to specific target gases. This is of high importance for the realization of a multi-gas sensor device capable of the clear discrimination of single gas components from a gas mixture. In this work we introduce our approach for the efficient screening of hybrid MOx–NP material combinations. We have developed a specific Si-platform chip along with a gas measurement setup which enables the simultaneous characterization of 16 chemical sensor structures in parallel. The Si-chips feature an array of Ti/Pt electrodes for contacting ultrathin MOx-sensing films, which are deposited by spray pyrolysis, and structured by photolithography to a size of 50 × 100 µm². On these platform chips we tested three different MOx (SnO₂, ZnO, and CuO) before and after functionalization with mono- and bimetallic NPs (such as Au, Pt, Pd, and NiPt) on several test gases (CO, HCmix, toluene, CO₂). Measurements were performed in a background gas of synthetic air at different relative humidity levels (25–75%) and at different operating temperatures up to 350 °C. We present the sensing performance results of various MOx-NP combinations, exhibiting an optimized response to specific target gases. Full article

Hydrogen is considered to be a very efficient and clean fuel since it is a renewable and non-polluting gas with a high energy density; thus, it has drawn much attention as an alternative fuel, in order to alleviate the issue of global warming caused by the excess use of fossil fuels. In this work, a novel Cu/ZnS/COF composite photocatalyst with a core–shell structure was synthesized for photocatalytic hydrogen production via water splitting. The Cu/ZnS/COF microspheres formed by Cu/ZnS crystal aggregation were covered by a microporous thin-film COF with a porous network structure, where COF was also modified by the dual-effective redox sites of C=O and N=N. The photocatalytic hydrogen production results showed that the hydrogen production rate reached 278.4 µmol g⁻¹ h⁻¹, which may be attributed to its special structure, which has a large number of active sites, a more negative conduction band than the reduction of H⁺ to H₂, and the ability to inhibit the recombination of electron–hole pairs. Finally, a possible mechanism was proposed to effectively explain the improved photocatalytic performance of the photocatalytic system. The present work provides a new concept, in order to construct a highly efficient hydrogen production catalyst and broaden the applications of ZnS-based materials. Full article

The efficiency of thin-film chalcogenide solar cells is dependent on their window layer thickness. However, the application of an ultrathin window layer is difficult because of the limited capability of the deposition process. This paper reports the use of atomic layer deposition (ALD) processes for fabrication of thin window layers for Cu(In_x,Ga_1−x)Se₂ (CIGS) thin-film solar cells, replacing conventional sputtering techniques. We fabricated a viable ultrathin 12 nm window layer on a CdS buffer layer from the uniform conformal coating provided by ALD. CIGS solar cells with an ALD ZnO window layer exhibited superior photovoltaic performances to those of cells with a sputtered intrinsic ZnO (i-ZnO) window layer. The short-circuit current of the former solar cells improved with the reduction in light loss caused by using a thinner ZnO window layer with a wider band gap. Ultrathin uniform A-ZnO window layers also proved more effective than sputtered i-ZnO layers at improving the open-circuit voltage of the CIGS solar cells, because of the additional buffering effect caused by their semiconducting nature. In addition, because of the precise control of the material structure provided by ALD, CIGS solar cells with A-ZnO window layers exhibited a narrow deviation of photovoltaic properties, advantageous for large-scale mass production purposes. Full article

As the energy crisis becomes worse, hydrogen as a clean energy source is more and more widely used in industrial production and people’s daily life. However, there are hidden dangers in hydrogen storage and transportation, because of its flammable and explosive features. Gas detection is the key to solving this problem. High quality sensors with more practical and commercial value must be able to accurately detect target gases in the environment. Emerging porous metal-organic framework (MOF) materials can effectively improve the selectivity of sensors as a result of high surface area and coordinated pore structure. The application of MOFs for surface modification to improve the selectivity and sensitivity of metal oxides sensors to hydrogen has been widely investigated. However, the influence of MOF modified film thickness on the selectivity of hydrogen sensors is seldom studied. Moreover, the mechanism of the selectivity improvement of the sensors with MOF modified film is still unclear. In this paper, we prepared nano-sized ZnO particles by a homogeneous precipitation method. ZnO nanoparticle (NP) gas sensors were prepared by screen printing technology. Then a dense ZIF-8 film was grown on the surface of the gas sensor by hydrothermal synthesis. The morphology, the composition of the elements and the characters of the product were analyzed by X-ray diffraction analysis (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Brunauer-Emmett-Teller (BET) and differential scanning calorimetry (DSC). It is found that the ZIF-8 film grown for 4 h cannot form a dense core-shell structure. The thickness of ZIF-8 reaches 130 nm at 20 h. Through the detection and analysis of hydrogen (1000 ppm), ethanol (100 ppm) and acetone (50 ppm) from 150 °C to 290 °C, it is found that the response of the ZnO@ZIF-8 sensors to hydrogen has been significantly improved, while the response to ethanol and acetone was decreased. By comparing the change of the response coefficient, when the thickness of ZIF-8 is 130 nm, the gas sensor has a significantly improved selectivity to hydrogen at 230 °C. The continuous increase of the thickness tends to inhibit selectivity. The mechanism of selectivity improvement of the sensors with different thickness of the ZIF-8 films is discussed. Full article

In this work, the properties of zinc oxide (ZnO) low-dimensional conductive oxide nanostructures in the aspect of their potential applications in microelectronics, in toxic gas sensing, as well as in water remediation, have been determined. ZnO nanostructured porous thin films deposited by DC reactive sputtering (RS) have been deposited on Si substrates at different temperature conditions. For surface properties and chemical morphology analysis, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) have been used. Thanks to these techniques, it was possible to obtain information on thin film surface modifications caused by the adsorption of atmospheric carbon dioxide, and by the adsorption of photodegradation products following the photocatalysis experiments. The ZnO thin films were tested for their photocatalytic properties under UV light irradiation. For this purpose, methylene blue was used as a dye model pollutant to evaluate the activity of the nanostructures. It was observed that the ZnO thin films are able to photocatalytically degrade methylene blue. These results demonstrate that properly selected zinc oxide nanostructures, currently used in toxic gas sensing, can find application in the removal of micropollutants such as dyes and pharmaceuticals present in wastewater. Full article

Due to the added value conferred by zinc oxide (ZnO) nanofiller, e.g., UV protection, antibacterial action, gas-barrier properties, poly(lactic acid) (PLA)–ZnO nanocomposites show increased interest for utilization as films, textile fibers, and injection molding items. The study highlights the beneficial effects of premixing ZnO in PLA under given conditions and its use as masterbatch (MB), a very promising alternative manufacturing technique. This approach allows reducing the residence time at high processing temperature of the thermo-sensitive PLA matrix in contact of ZnO nanoparticles known for their aptitude to promote degradation effects onto the polyester chains. Various PLA–ZnO MBs containing high contents of silane-treated ZnO nanoparticles (up to 40 wt.% nanofiller specifically treated with triethoxycaprylylsilane) were produced by melt-compounding using twin-screw extruders. Subsequently, the selected MBs were melt blended with pristine PLA to produce nanocomposite films containing 1–3 wt.% ZnO. By comparison to the more traditional multi-step process, the MB approach allowed the production of nanocomposites (films) having improved processing and enhanced properties: PLA chains displaying higher molecular weights, improved thermal stability, fine nanofiller distribution, and thermo-mechanical characteristic features, while the UV protection was confirmed by UV-vis spectroscopy measurements. The MB alternative is viewed as a promising flexible technique able to open new perspectives to produce more competitive multifunctional PLA–ZnO nanocomposites. Full article

A novel strategy for large-scale synthesis of ZnO nanowire film is reported, which inherits the advantages of the solution-phase method and seeded growth process, such as low-temperature, efficient, economical, facile and flexible. It is easy to implement on various metals through room-temperature electrodeposition, followed by hydrothermal treatment at 90 °C, and suitable for industrialized production. The ZnO nanowires with an average wire diameter about 40 nm are in situ grown from and on nanocrystalline zinc coating, which forms a strong metallurgical bonding with the substrates. The p-type ZnO nanowire film has a well-preferred orientation along the (100) direction and a wurtzite structure, thereby displaying an effective photocatalytic capability for carcinogenic Cr⁶⁺ ions and CO₂ greenhouse gas reduction under visible light irradiation. In addition to these features, the ZnO nanowire film is easy to recycle and, therefore, it has broad application prospects in contaminant degradation and renewable energy. Full article

As a wide band-gap and direct transition semiconductor material, ZnO has good scintillation performance and strong radiation resistance, but it also has a serious self-absorption phenomenon that affects its light output. After being doped with Ga, it can be used for the scintillator of ultra-fast scintillating detectors to detect X-ray, gamma, neutron, and charged particles with extremely fast response and high light output. Firstly, the basic properties, defects, and scintillation mechanism of ZnO crystals are introduced. Thereafter, magnetron sputtering, one of the most attractive production methods for producing ZnO:Ga film, is introduced including the principle of magnetron sputtering and its technical parameters’ influence on the performance of ZnO:Ga. Finally, ZnO:Ga film’s application research status is presented as a scintillation material in the field of radiation detection, and it is concluded that some problems need to be urgently solved for its wider application. Full article