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This research aimed to augment the properties of interfibre interfaces through surface treatment with ZnO nanorods while simultaneously modifying the matrix with graphene nanoplatelets. The strategic approach of this research focused on synergizing these interventions to enhance the mesomechanical, and macromechanical properties, which are specifically targeted at improving the performance of aircrew helmets. This study investigated the effectiveness of these enhancements in improving the mechanical performance of aircrew helmets. The synergy of integrating ZnO nanorods and doped GNPs into Kevlar fabric resulted in a 29% increase in impact energy absorption compared to that of the standard Kevlar composite. Furthermore, the composite samples underwent thorough analysis through techniques such as thermogravimetric analysis (TGA), Raman spectroscopy, Fourier‐transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM) imaging. The findings indicate that incorporating 1% graphene nanofillers into Kevlar during the fourth seed cycle of ZnO treatment yields favorable mechanical performance characteristics. SEM at 50 KX magnification provided detailed visualization of the ZnO nanorods grafted onto the fabric substrates, with subsequent evaluation of the morphological damage and fractography of the impacted composites. The findings of this research hold significance for advancing the understanding of composite material behavior under impact loads and contribute to ongoing efforts to enhance the durability and performance of structural composites in diverse applications. Highlights: Synergistic treatment with ZnO nanorods and graphene nanoplatelets boosted Kevlar composite properties for aircrew helmets.Adding 1% graphene during ZnO treatment increased impact energy absorption by 29%.Comprehensive analysis validated treatment efficacy, showing substantial mechanical improvements.The research advances composite understanding, paving the way for durable, high‐performance materials for applications like aircrew helmets. [ABSTRACT FROM AUTHOR]

In the present study we have disclosed here that ZnO nanorod (ZnO‐NR) can effectively be used as a catalyst for various C−C bond formation reactions, i. e. allylation, as well as one‐pot three components conjugate addition and Knoevenagel‐allylation of isatins. The corresponding products were obtained with good to excellent yields under solvent‐free conditions in most cases at RT. The catalyst was successfully recycled for up to five cycles for allylation reaction and one pot three components Knoevenagel‐allylation reaction of isatin. X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the structure and morphology of the catalyst. [ABSTRACT FROM AUTHOR]

Increasing environmental issues have emerged due to various pharmaceutical wastes. These wastes are difficult to remove by treatment due to their continuous consumption and long-term persistence. We have synthesized two different shapes of zinc oxide (ZnO) nanoparticles as catalysts—nanorod (ZnO–NR) and oval-shape (ZnO–OS). A comparative performance of these two catalyst shapes on photocatalytic degradation of rifampicin (RIF) in water—a first-line anti-tuberculosis drug, was carried out. ZnO–NR showed three times higher normalized first-order degradation rate constant of RIF under UV light than that with ZnO–OS. This is due to: (i) specific surface area and specific pore volume of ZnO–NR being 25 and six times higher, respectively, than ZnO–OS; (ii) oxygen vacancy in ZnO–NR being 1.7 times higher than ZnO–OS; (iii) slightly lower band gap energy in ZnO–NR than ZnO–OS, adding to carrier concentration; and (iv) ZnO–NR additionally showing 12.4% chemisorbed oxygen also. Towards RIF degradation, ZnO–NR shows a much improved synergistic effect than ZnO–OS under UV light, as ZnO–NR under UV light is found to give 2.7 times higher degradation than when the catalyst and UV act independently and hence only additively. Therefore, this study is helpful in tuning the shape-dependent chemical reactivity of nanoparticles in water treatment. [ABSTRACT FROM AUTHOR]

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Developing highly sensitive and selective non-enzymatic electrochemical biosensors for disease biomarker detection has become challenging in healthcare applications. However, advances in material science are opening new avenues for creating more dependable biosensing technologies. In this context, the present work introduces a novel approach by engineering a hybrid structure of zinc oxide nanorod (ZnO NR) modified with iron oxide nanoparticle (Fe2O3 NP) on an FTO electrode. This Fe2O3 NP-ZnO NR hybrid material functions as a nanozyme, facilitating the catalysis of cholesterol and enabling the direct transfer of electrons to the fluorine-doped tin oxide (FTO) electrode, limiting the need for costly and traditional enzymes in the detection process. This innovative non-enzymatic cholesterol biosensor showcases remarkable sensitivity, registering at 642.8 μA/mMcm2 within a linear response range of up to 9.0 mM. It also exhibits a low detection limit (LOD) of ∼12.4 μM, ensuring its capability to detect minimal concentrations of cholesterol accurately. Moreover, the developed biosensor displays exceptional selectivity by effectively distinguishing cholesterol molecules from other interfering biological species, while exhibiting outstanding stability and reproducibility. Our findings indicate that the Fe2O3 NP-ZnO NR hybrid nanostructure on the FTO electrode holds promise for enhancing biosensor stability. Furthermore, the present device fabrication platform offers versatility, as it can be adapted with various enzymes or modified with different metal oxides, potentially broadening its applicability in a wide range of biomarkers detection.

In this work, we report a self-powered quasi-solid-state photodetector (PD) device prepared from flexible two-dimensional (2D) nanocomposites of a zinc oxide nanowire (ZnO-NW) in various weight percents (5, 10, 30, 50%) and Ti3C2Tx (MXene) paper, constructed with manganese (Mn)-doped zinc oxide nanorods (ZnO NRs) using an ionic gel electrolyte and carbon paper. All PD performance tests revealed that 5% ZnO-MXene-based devices were superior to the other samples. The maximum detectivity of 1.44 × 1013 Jones at 367 nm (0.1 mW cm–2) and zero bias was calculated for the 5% ZnO-MXene-based device. Additionally, a very high on/off ratio of nearly 106, which is approximately 35-fold higher than that of the 50% ZnO-MXene-based PDs, was achieved for 5% ZnO-MXene PD at a zero bias under 367 nm (2.52 mW cm–2) illumination. The rise time for this device was 9.25 ms. Furthermore, the PD device exhibited excellent stability by enduring 1000 s of light on/off cycles. As a result, a simple, compact, and cost-effective self-powered ZnO-NW:MXene-based PD configuration showed fast photoresponse and excellent detecting performance. [ABSTRACT FROM AUTHOR]

The mature processes of metal oxide semiconductors (MOS) have attracted considerable interest. However, the low sensitivity of metal oxide semiconductor gas sensors is still challenging, and constrains its practical applications. Bimetallic nanoparticles are of interest owing to their excellent catalytic properties. This excellent feature of bimetallic nanoparticles can solve the problems existing in MOS gas sensors, such as the low response, high operating temperature and slow response time. To enhance acetone sensing performance, we successfully synthesized Au-Pd/ZnO nanorods. In this work, we discovered that Au-Pd nanoparticles modified on ZnO nanorods can remarkably enhance sensor response. The Au-Pd/ZnO gas sensor has long-term stability and an excellent response/recovery process. This excellent sensing performance is attributed to the synergistic catalytic effect of bimetallic AuPd nanoparticles. Moreover, the electronic and chemical sensitization of noble metals also makes a great contribution. This work presents a simple method for preparing Au-Pd/ZnO nanorods and provides a new solution for the detection of acetone based on metal oxide semiconductor. [ABSTRACT FROM AUTHOR]

Solar-selective and high entropy materials are one of the key factors for thermal applications. CuCoMnO x (CCMO) spinel compound is also a suitable material for this purpose due to its spin-allowed transitions in partially filled d orbitals. In this study, the CCMO absorber compound was coated on ZnO nanorod-coated aluminum (Al) substrates for the first time by the sol-gel dip-coating method, and its optical, structural, and morphological properties were examined. According to the results obtained, ZnO nanorods increased the active surface area of the Al substrate and accordingly increased the absorptance value of the CCMO material from 87 % to 94 %. Analyzes performed with FT-IR spectrometry showed that the thermal emittance values were 90 % and 67 % for Al/CCMO and Al/ZnO/CCMO samples, respectively. The thermal emittance reduced by around 25 % with the use of ZnO nanorods on the Al substrates in the wavelength range of 2.5 μm–25 μm. The photocatalytic effect of this spinel compound was also investigated. The degradation spectra of organic methylene blue (MB) solution within 120 min were examined with UV–Vis spectroscopy, and the degradation efficiency increased by 23 % in the presence of ZnO nanorods. The obtained results showed that ZnO nanorod structures significantly changed both the solar and photocatalytic properties of the CCMO compound. [ABSTRACT FROM AUTHOR]

We demonstrate the all-solution-based fabrication of metal-nanodot-decorated semiconductor nanorod structures, with the entire process performable at very low or room temperatures. On the surfaces of semiconducting ZnO nanorods (ZNRs) hydrothermally grown on a solution-processed Ag layer at 90 °C, Ag nanodots are reduced from Ag cations in an ionic solution at room temperature by taking UV-induced electrons from ZNRs. Ag nanodots can be deposited at a specific position (top, bottom, or whole region) of the ZNRs by using a controlled ionic Ag solution coating method. We investigate the UV-assisted room-temperature photoreduction (RTPR) mechanism by focusing on the roles of ZnO and solvent. We further examine that the size, density, and spatial distribution of Ag nanodots can be controlled by regulating the concentration of the ionic Ag solution and RTPR time. The resulting hybrid Ag/ZNR architecture, processable on a large-area flexible substrate, exhibits significantly enhanced photocurrent level, responsivity, and selectivity for the incident UV light due to the localized surface plasmon resonance of the Ag nanodots and rapid electron transfer across the Ag/ZnO interface. Our all-solution-based room-temperature approach offers an environmentally sustainable, low-cost, and scalable method for the design and fabrication of metal-nanodot-decorated semiconductor nanostructures applicable to optoelectronic transducers and many other applications. [ABSTRACT FROM AUTHOR]

Mechanical strain has been shown to be a versatile and tunable means to control various properties of nanomaterials. In this work, we investigate how strain applied to individual ZnO nanorods (NRs) can affect the fluorescence signals originated from external sources of bioanalytes, which are subsequently coupled and guided onto the NRs. Specifically, we determine how factors such as the NR length and protein concentration can influence the strain-induced changes in the waveguided fluorescence intensity along the NRs. We employ a protein of tumor necrosis factor-α (TNF-α) and a fluorophore-labeled antibody in a model immunoassay reaction, after which Alexa488-TNF-α immunocomplex is formed on ZnO NRs. We elucidate the relationships between the types as well as amounts of strain on the NRs and the fluorescence intensity originated from the Alexa488-TNF-α immunocomplexes. We show that tensile (compressive) strain applied to the NR leads to an increase (decrease) in the waveguided fluorescence signals. By assessing important optical phenomena such as fluorescence intensification on nanorod ends (FINE) and degree of FINE (DoF), we confirm their linear dependence with both the types and amounts of strain. Furthermore, the strain-induced changes in both FINE and DoF are found to be independent of protein concentration. We determine that NR length plays a critical role in obtaining high strain-dependence of the measured fluorescence signals. Particularly, we ascertain that longer NRs yield larger changes in both FINE and DoF in response to the applied strain, relative to shorter ones. In addition, longer NRs permit higher linear correlation between the protein concentration and the waveguided fluorescence intensity. These outcomes provide valuable insight into exploiting strain to enhance the detection of optical signals from bioanalytes, thus enabling their quantifications even at ultra-trace levels. Coupled with the use of individual ZnO NRs demonstrated in our measurements, this work may contribute to the development of a miniaturized, highly sensitive biosensor whose signal transduction is best optimized by the application of strain. [ABSTRACT FROM AUTHOR]

In this study, we employed a chemical solution method to grow zinc oxide (ZnO) nanorods on SnO2:F (FTO) substrates as photoelectrodes for dye-sensitized solar cells (DSSCs). The influence of varying ZnO nanorod dimensions on cell performance was investigated. Specifically, we explored the effects of nanorod length and diameter on dye adsorption capacity and photovoltaic conversion efficiency. Characterization techniques such as electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM) were utilized to analyze the ZnO nanorods. Our results demonstrate that the sequential growth technique allows for control over the length and diameter of ZnO nanorods, thereby modulating their optoelectronic properties. XRD and FE-SEM analyses revealed that the surface morphology of the ZnO nanorods impacts dye adsorption capacity and photovoltaic conversion efficiency. EIS measurements further indicated a significant influence of dye adsorption on the electron lifetime of ZnO nanorods. Overall, this study highlights the potential of multi-step growth of ZnO nanorods to optimize the performance of dye-sensitized solar cells by tuning their morphology and surface properties. [ABSTRACT FROM AUTHOR]

The mature processes of metal oxide semiconductors (MOS) have attracted considerable interest. However, the low sensitivity of metal oxide semiconductor gas sensors is still challenging, and constrains its practical applications. Bimetallic nanoparticles are of interest owing to their excellent catalytic properties. This excellent feature of bimetallic nanoparticles can solve the problems existing in MOS gas sensors, such as the low response, high operating temperature and slow response time. To enhance acetone sensing performance, we successfully synthesized Au-Pd/ZnO nanorods. In this work, we discovered that Au-Pd nanoparticles modified on ZnO nanorods can remarkably enhance sensor response. The Au-Pd/ZnO gas sensor has long-term stability and an excellent response/recovery process. This excellent sensing performance is attributed to the synergistic catalytic effect of bimetallic AuPd nanoparticles. Moreover, the electronic and chemical sensitization of noble metals also makes a great contribution. This work presents a simple method for preparing Au-Pd/ZnO nanorods and provides a new solution for the detection of acetone based on metal oxide semiconductor.

The environment and global healthcare are at risk from oily wastewater accumulation and spills. Hence, porous sponge materials are widely sought for remedial oil cleanups. Materials with superhydrophobic and photocatalytic characteristics are implemented for extensive use besides oil–water separation, self‐cleaning, and removal of dyes. Regardless of the various upsides, few materials display both of these features jointly. Most nanomaterial photocatalysts are susceptible to the action of ultraviolet (UV) light irradiation, which often inhibits their hydrophobicity. Here in this work, a photocatalyst such as ZnO was coated on a porous 3‐D melamine sponge (MS). To preserve the hydrophobicity without sacrificing the photocatalytic behavior, ZnO coated melamine sponge was modified with transparent polydimethylsiloxane (PDMS) to obtain MS/ZnO/PDMS. The obtained superhydrophobic photocatalytic sponge exhibits exceptional oil adsorption capacity, superior stability even under severe conditions and the ability to remove organic dyes. Remarkably, the sponge exhibits outstanding compressive strength and fire resistance properties, indicating the possible utilization in a prolonged practical execution. As a result, this technique might pave the way for the creation of a comprehensive design for an improved superhydrophobic photocatalytic sponge with high stability and recyclability. [ABSTRACT FROM AUTHOR]

NO2 is a very dangerous and toxic gas and is prone to cause acid rain in high humidity environments, so it is essential to prepare a real-time monitoring and humidity immunity NO2 sensor. WO3 nanomaterials are commonly applied to detect NO2, but their poor immunity to humidity is still a critical limitation for the application. ZnO-nanorod-decorated WO3 nanosheets coated with ZIF-71 (ZnO@ZIF-71/WO3) composites prepared by an in situ growth method displayed excellent gas sensing performance and good humidity immunity to detect NO2. Compared to WO3 nanosheets and ZnO-nanorod-decorated WO3 nanosheets (ZnO/WO3) heterojunction composites grown on ceramic substrates in situ, ZnO@ZIF-71/WO3 presented excellent selectivity, good long-term stability, and a remarkably high response of about 947.96 to 100 ppm NO2 at 180 °C, which is 3.07 times higher than that of the ZnO/WO3 sensor and 4.59 times higher than that of the pure WO3 sensor. Even at a relative humidity of 85%, the response of ZnO@ZIF-71/WO3 to NO2 remained essentially constant. The functional ZIF-71 layer not only improved the humidity immunity of ZnO@ZIF-71/WO3 but also enhanced the sensitivity and selectivity performance to NO2 at low operating temperatures. The ZnO@ZIF-71/WO3 sensor still provided a response of 88.41 to 100 ppm NO2 at room temperature. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) spectroscopy has attracted increasing attention due to its high spectral reproducibility and unique selectivity to target molecules. Here, a facile approach is proposed to prepare Ag nanoparticles modified ZnO nanorod arrays (Ag/ZnO NR arrays). Ag nanoparticles were densely decorated on the surface of ZnO nanorods through silver mirror reaction and subsequent seed-assisted electrodeposition. The prepared Ag/ZnO NR arrays can be used as a sensitive, uniform, and repeatable SERS substrate for the rapid detection of organic dye molecules and biomolecules with concentrations higher than the corresponding limits of detection (LODs). The LODs for rhodamine 6G (R6G), 4-aminothiophenol (PATP) and adenine are calculated to be 1.0 × 10−13 M, 1.6 × 10−12 M and 3 × 10−11 M, respectively. The enhancement factor (EF) of the SERS substrate is estimated to be as high as ~2.7 × 108 when detecting 10−10 M R6G. Particularly, the as-synthesized substrate exhibits high selectivity to multiple components. In addition, the fabricated Ag/ZnO NR arrays can be recycled due to their superior self-cleaning ability and can realize photocatalytic degradation of R6G in water within 1 h driven by UV light, showing that the three-dimensional recyclable SERS substrates have wide applications in environmental pollution monitoring and biomedical analysis. [ABSTRACT FROM AUTHOR]

Soot particulate is one of the most important pollutants emitted from diesel engines. A monolithic wall-flow diesel particulate filter (DPF) is a commercial technology for the removal of soot via filtration and subsequent combustion with/without catalysts. Herein, in situ grown ZnO nanorods on DPFs are applied to improve both soot and potassium (K)-based catalyst dispersion efficiency and thus enhancing the activity of DPF regeneration. The pretreatment and hydrothermal synthesis procedures for the homogenously covered ZnO nanorod arrays were specifically investigated on aluminum titanate (Al2TiO5) and silicon carbide (SiC) and compared with cordierite (Mg2Al4Si5O18). Potassium carbonate (K2CO3) is further supported on these monolithic substrates with in situ grown ZnO nanorods acting as catalytic active components for soot combustion. The coexistence of in situ grown ZnO nanorods and K active species on the three monoliths leads to much better soot combustion activity than those bare monoliths. The ZnO nanorods can not only trap soot to improve the contact efficiency between soot and catalysts, but also disperse the active K species. This demonstrates a promising strategy to develop highly active catalytic DPF for diesel soot removal.

Mechanical strain has been shown to be a versatile and tunable means to control various properties of nanomaterials. In this work, we investigate how strain applied to individual ZnO nanorods (NRs) can affect the fluorescence signals originated from external sources of bioanalytes, which are subsequently coupled and guided onto the NRs. Specifically, we determine how factors such as the NR length and protein concentration can influence the strain-induced changes in the waveguided fluorescence intensity along the NRs. We employ a protein of tumor necrosis factor-α (TNF-α) and a fluorophore-labeled antibody in a model immunoassay reaction, after which Alexa488-TNF-α immunocomplex is formed on ZnO NRs. We elucidate the relationships between the types as well as amounts of strain on the NRs and the fluorescence intensity originated from the Alexa488-TNF-α immunocomplexes. We show that tensile (compressive) strain applied to the NR leads to an increase (decrease) in the waveguided fluorescence signals. By assessing important optical phenomena such as fluorescence intensification on nanorod ends (FINE) and degree of FINE (DoF), we confirm their linear dependence with both the types and amounts of strain. Furthermore, the strain-induced changes in both FINE and DoF are found to be independent of protein concentration. We determine that NR length plays a critical role in obtaining high strain-dependence of the measured fluorescence signals. Particularly, we ascertain that longer NRs yield larger changes in both FINE and DoF in response to the applied strain, relative to shorter ones. In addition, longer NRs permit higher linear correlation between the protein concentration and the waveguided fluorescence intensity. These outcomes provide valuable insight into exploiting strain to enhance the detection of optical signals from bioanalytes, thus enabling their quantifications even at ultra-trace levels. Coupled with the use of individual ZnO NRs demonstrated in our measurements, this work may contribute to the development of a miniaturized, highly sensitive biosensor whose signal transduction is best optimized by the application of strain.

A dicationic ionic liquid, [BisOct (MIM)2][2Br], was successfully synthesized and used for the hydrothermal preparation of rod-shaped nanostructured ZnO with a basic hexagonal wurtzite growth unit. A hydrophobic nanocomposite coating of ZnO with polystyrene (ZnO/PS) was fabricated and characterized using Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The effect of nanocomposite coatings with different percentages of ZnO (1, 3, and 5 wt.%) was explored for mild steel corrosion protection in NaCl (3.5 wt.%) saline solution using electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), and FE-SEM. The EIS results showed a significant increase in the charge transfer resistance, with the highest value of 4.83 × 105 Ω cm2 in the presence of PS/ZnO-5, which acted as an efficient passivating barrier for the diffusion of corrosive ions. The results revealed that embedding ZnO nanorods significantly enhanced the corrosion-protection properties of the PS coating. The results of this study may contribute to the design of anticorrosive coatings for industrial applications.

Highly selective and sensitive glucose biosensor is built based on flexible and biocompatible branched carbon/ZnO core-shell nanostructures modified with GOx/CS layers. The hybrid biosensor provides an ideal platform for implantable device fabrication that can perform glucose sensing in real-time analysis. [Display omitted] • A feasible construction of flexible and 3D hybrid glucose biosensor by successfully immobilization of the GOx on branched carbon/ZnO core–shell nanostructures. • The glucose biosensor showed excellent stability, selectivity and detection sensitivity for glucose in clinical range of 3.9 mM to 5.5 mM at physiological pH conditions. • A highly efficient direct electron communication between the redox center of GOx and electrode surface becomes feasible due to the large surface area provided by the branched carbon/ZnO core–shell nanostructures. Reliable glucose monitoring at physiological pH and clinical practical range is critical for appropriate diabetes management which remains one of a major health concern. Herein, we describe the construction of flexible and 3D hybrid electrode for glucose sensing by successful immobilization of the GOx on branched carbon/ZnO core–shell nanostructures electrode. The microstructure, morphology and device properties of glucose sensor was systemically characterized by using HRTEM, SEM, FT-IR, and electrochemical analysis. The branched carbon/ZnO core–shell nanostructure sensor showed reliable stability, selectivity and remarkable sensitivity (i.e., 32.48 (±0.04) µA mM−1 cm−2) for glucose in clinical range at physiological pH conditions. The mediator less direct electron communication between the electrode surface and the redox center (FADH & FAD) was also analyzed comprehensively, which concludes an efficient direct electron communication (DET). This enhanced DET can be attributed to the larger surface area provided by the branched carbon/ZnO core–shell nanostructure and also favorable orientation of GOx which allows close proximity of the redox center and the electrode surface. It is believed that such kind of sensors could provide an ideal platform for continuous glucose monitoring (CGM) device fabrication which could perform glucose sensing in real-time and in-vivo analysis. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) nanorods have sparked widespread attention in regard to their potential in photocatalytic pollution treatment. This work investigates the structural characteristics of ZnO, notably the nanorod morphology, and their relevance to photocatalytic activity. Experiments were carried out to determine the effect of sol-gel/calcination and solvothermal methods and the addition of acetic acid (AA) on ZnO characteristics. The results revealed that ZnO nanorods had lattice constants consistent with prior works, with both synthesis processes promoting development on the (002) and (200) planes along the c-axis. Solvothermal treatment yielded nanorods with increased surface area. The addition of AA resulted in lower surface area but better photocatalytic degradation rates when compared to AA-free counterparts, particularly in solvothermally-treated samples. ZnO nanorods formed solvothermally with AA had a photocatalytic degradation rate comparable to literature (0.021 ± 0.003 h−1), (002)-orientation, crystallite size of 24.46 ± 2.47 nm, and a surface area of 10.61 m2/g. Overall, the data indicate that the presence of defect states on the surface of wurtzite ZnO has a significant impact on photocatalytic activity, outweighing the effects of surface area and E g. [Display omitted] • Calcination and solvothermal treatments produced c-axis oriented ZnO nanorods, with solvothermal ones having higher photocatalytic performance. • Acetic acid decreased the surface area and introduced surface defects during solvothermal treatment and increased the photocatalytic performance. • Energy band gap was not influenced by the process type or acetic acid addition. [ABSTRACT FROM AUTHOR]

To remove the Ciprofloxacin (CIP) from aqueous solution, ZnO–Ag-Gp nanocomposite exhibited efficient photocatalytic properties. The biopersistent CIP is pervasive in surface water and also hazardous to human and animal health. This study utilized the hydrothermal technique to prepare Ag-doped ZnO hybridizing Graphite (Gp) sheet (ZnO–Ag-Gp) to degrade pharmaceuticals pollutant CIP from an aqueous medium. The structural and chemical compositions of the photocatalysts were determined by XRD, FTIR and XPS analysis. FESEM and TEM images revealed the nanorod ZnO with round shape Ag distributed on a Gp surface. The reduced bandgap of the ZnO–Ag-Gp sample enhanced the photocatalytic property which was measured by using UV–vis Spectroscopy. Dose optimization study found that 1.2 g/L is optimum for single (ZnO) and binary (ZnO-Gp and ZnO–Ag), where 0.3 g/L ternary (ZnO–Ag-Gp) exhibited maximum degradation efficiency (98%) within 60 min for 5 mg/L CIP. Pseudo 1st order reaction kinetics rate was found highest for ZnO–Ag-Gp (0.05983 min−1) and it decreased to 0.03428 min−1 for annealed sample. Removal efficiency decreased to only 90.97% at 5th run and hydroxyl radicals played a vital role to degrade CIP from aqueous solution. UV/ZnO–Ag-Gp will be a promising technique to degrade wide-ranging pharmaceutical antibiotics from the aquatic medium.

The strain occurs spontaneously at the heterogeneous interfaces of virtually all crystalline materials. Consequently, the analysis across multiple interfaces requires a complementary characterization scheme with a resolution that fits the deformation scale. By implementing two-photon confocal laser scanning nanoscopy with an axial resolution of 10 nm, we extract the surface strain from the photoluminescence (PL) spectra, epitomized by a 2-fold enhancement at the tapered tips in comparison to the substrate of ZnO nanorods. We firstly traced the well-established contribution from quantum confinement (QC) to PL shift in three geometrically classified regions: (I) a strongly tapered region where the diameter increases from 3 to 20 nm; (II) a weakly tapered region with a gradually increasing diameter from 20 to 58 nm; (III) round cylindrical region interfacing the sapphire substrate. The measured PL shift influenced by the deformation is significantly stronger than the attained QC effect. Particularly, surface strain at the strongly tapered region turned out to drastically increase the PL shift which matches well with the analysis based on the surface to volume ratio incorporating mechanical parameters such as the compliance tensor component, strain dislocation constant, and surface stress. The surface strain increased at a lower temperature, further disclosing its inherent dependence on the thermal expansion coefficients in clear contrast to the temperature-invariant characteristics of QC. [ABSTRACT FROM AUTHOR]

We report on employing in vitro biosynthesized ZnO nanoparticles using L. pubescens shoot methanol extract (50 and 100 mg LP–ZnO NPs) to examine their antimicrobial efficacy against Pseudomonas aeruginosa (ATCC27853), Staphylococcus aureus (ATCC 29213), Aspergillus niger (ATCC 16404 NA), and Aspergillus terreus (TCC 10029). The formation and stability of the investigated ZnO nanoparticles were proven by transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), UV–vis spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The ZnO nanoparticles were rod-shaped (width: 10.76–30.93 nm). The nanoparticles in dimethyl sulfoxide (DMSO) outperformed their water counterparts in terms of their zones of inhibition (ZIs) (marginal means of 12.5 and 8.19 mm, respectively) and minimum inhibition concentrations (MICs) (means of 4.40 and 8.54 mg/mL, respectively). The ZI means for S. aureus, P. aeruginosa, A. terreus, and A. niger were 10.50, 6.13, 12.5, and 11.5 mm, respectively. When treating S. aureus and P. aeruginosa, the ZI of the 50 mg LP–ZnO NPs in water was better (14 mm), with a lower MIC and lower minimum bactericidal/fungicide concentrations (MBC/MFC) (7.22 and 4.88 mg/mL, respectively) than the ZnO and control drugs. The SEM images showed cellular alterations in the surface shapes after the LP–ZnO-NP treatments. Biosynthesized LP–ZnO NPs could have beneficial antibacterial properties, which could allow for future contributions to the development of new antimicrobial drugs. [ABSTRACT FROM AUTHOR]

Developing highly sensitive and selective non-enzymatic electrochemical biosensors for disease biomarker detection has become challenging in healthcare applications. However, advances in material science are opening new avenues for creating more dependable biosensing technologies. In this context, the present work introduces a novel approach by engineering a hybrid structure of zinc oxide nanorod (ZnO NR) modified with iron oxide nanoparticle (Fe 2 O 3 NP) on an FTO electrode. This Fe 2 O 3 NP-ZnO NR hybrid material functions as a nanozyme, facilitating the catalysis of cholesterol and enabling the direct transfer of electrons to the fluorine-doped tin oxide (FTO) electrode, limiting the need for costly and traditional enzymes in the detection process. This innovative non-enzymatic cholesterol biosensor showcases remarkable sensitivity, registering at 642.8 μA/mMcm 2 within a linear response range of up to 9.0 mM. It also exhibits a low detection limit (LOD) of ∼12.4 μM, ensuring its capability to detect minimal concentrations of cholesterol accurately. Moreover, the developed biosensor displays exceptional selectivity by effectively distinguishing cholesterol molecules from other interfering biological species, while exhibiting outstanding stability and reproducibility. Our findings indicate that the Fe 2 O 3 NP-ZnO NR hybrid nanostructure on the FTO electrode holds promise for enhancing biosensor stability. Furthermore, the present device fabrication platform offers versatility, as it can be adapted with various enzymes or modified with different metal oxides, potentially broadening its applicability in a wide range of biomarkers detection., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

This work demonstrated a ZnO-coated optical fiber sensor for the detection of a volatile organic compound (VOC) biomarker for diabetes for detecting isopropanol (IPA) markers. A coreless silica fiber (CSF) was connected to a single-mode fiber (SMF) at both ends to achieve a SMF–CSF–SMF structure. CSF is the sensing region where multimode interference (MMI) generates higher light interaction at the interface between the fiber and sensing medium, leading to enhanced sensitivity. Optimization of the CSF length was conducted numerically to attain the highest possible coupling efficiency at the output. Surface functionalization was achieved via hydrothermal growth of ZnO nanorods directly onto the CSF at low temperatures. The optical fiber-based sensor was successfully fabricated and tested with 20%, 40%, 60%, 80%, and 100% of IPA. The sensor response was recorded using an optical spectrometer and analyzed for sensor sensitivity. The fabricated sensor shows the potential to detect isopropanol with the sensitivity of 0.053 nm/%IPA vapor. Further improvement of the sensor sensitivity and selectivity is also proposed for future work. [ABSTRACT FROM AUTHOR]

The sensing characteristics of toluene gas are monitored by fabricating ZnO nanorod structures. ZnO nanostructured sensor materials are produced on a Zn film via an ultrasonic process in a 0.01 M aqueous solution of C6H12N4 and Zn(NO3)2∙6H2O. The response of the sensors subjected to heat treatment in oxygen and nitrogen atmospheres is improved by 20% and 10%, respectively. The improvement is considered to be correlated with the increase in grain size. The relationship between the heat treatment and sensing characteristics is evaluated. [ABSTRACT FROM AUTHOR]

ZnO nanorods co-doped with indium and gallium were grown on p-GaN films by low-temperature hydrothermal method. The results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDS) show that indium and gallium have been dissolved in the ZnO lattice. Scanning electron microscope (SEM) observation shows that ZnO nanorods have good c-axis orientation. With increasing indium and gallium co-doping concentration, the diameter of the nanorods decreases and the density increases. XRD results show that the incorporation of indium and gallium causes the lattice constant of ZnO to increase, resulting in the (002) diffraction peak shifting to a low angle direction. At the same time, the optical properties of ZnO are affected by the co-doping of In and Ga. The UV emission peaks of co-doped ZnO nanorods all show a slight red shift, which is the result of the combined effects of surface resonance and band gap reforming. The I-V characteristics curves show that the n-ZnO nanorods/p-GaN heterojunction has better conductivity with increasing indium and gallium co-doping concentration. [ABSTRACT FROM AUTHOR]

This study explores the improved ultraviolet (UV) photodetection performance of ZnO nanorods (ZnO NRs) decorated with BaTiO 3 nanoparticles (BT NPs) synthesized using a novel vapor-thermal method (VTM) leading to the formation of a heterojunction upon UV activation that enhances charge separation and reduces charge carrier's recombination. Initially, ZnO NRs were prepared via a hydrothermal method followed by decoration with BT NPs using the innovative VTM process. To elucidate the morphology and composition of the BT-decorated ZnO NRs, a comprehensive characterization was performed using various techniques, including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Photoluminescence (PL) and diffuse reflectance spectroscopy (DRS) are employed to study electronic band structure of the BT decorated and undecorated samples. The BT nanoparticle-decorated ZnO NRs exhibited a higher photodetection performance compared to bare ZnO NRs under 365 nm UV light illumination. This improvement is manifested by a lower dark current, a faster rise time (from 2 s to 0.75 s), a shorter decay time (from 46 s to 0.96 s), and higher sensitivity (from 57 to 135). These findings demonstrate the promising potential of the BT nanoparticle-decorated ZnO NRs for application in high-performance UV photodetectors. [Display omitted] • Decoration of ZnO nanorods with BT nanoparticles (7–11 nm) by a novel VT method. • PL emission enhancement and shift in the absorption edge due to BT decoration. • UV- activation of heterojunctions formed at the interface of BT NPs and ZnO NRs. • Lower noise, faster speed and more sensitive material structure for UV PDs. [ABSTRACT FROM AUTHOR]

In this study, different chemical methods were used to synthesize ZnO nanorod, TiO2 nanotube and ZnO/TiO2 nanostructure as high sensitivity vapor sensor for ethanol. The surface topography of ZnO nanorod, TiO2 nanotube and ZnO/TiO2 was studied by using the scanning electron microscopy (SEM). The X-rays diffraction showed the appearance of (101) ZnO which has single crystalline with a hexagonal wurtzite while TiO2 has been crystallized in a tetragonal with the preferential orientation of the crystallinity with the prominent (111). The relation between resistance-time showed high sensitivity for ZnO/TiO2 and was found to be around 20-80% at different working temperature. ZnO/TiO2 sensor was the most sensitive to ethanol vapor.

Abstract As an important photoconductive hybrid material, perylene/ZnO has attracted tremendous attention for photovoltaic-related applications, but generally faces a great challenge to design molecular level dispersed perylenes/ZnO nanohybrids due to easy phase separation between perylenes and ZnO nanocrystals. In this work, we reported an in-situ reaction method to prepare molecular level dispersed H-aggregates of perylene bisimide/ZnO nanorod hybrids. Surface photovoltage and electric field-induced surface photovoltage spectrum show that the photovoltage intensities of nanorod hybrids increased dramatically for 100 times compared with that of pristine perylene bisimide. The enhancement of photovoltage intensities resulting from two aspects: (1) the photo-generated electrons transfer from perylene bisimide to ZnO nanorod due to the electric field formed on the interface of perylene bisimide/ZnO; (2) the H-aggregates of perylene bisimide in ZnO nanorod composites, which is beneficial for photo-generated charge separation and transportation. The introduction of ordered self-assembly thiol-functionalized perylene-3,4,9,10-tetracarboxylic diimide (T-PTCDI)/ ZnO nanorod composites induces a significant improvement in incident photo-to-electron conversion efficiency. This work provides a novel mentality to boost photo-induced charge transfer efficiency, which brings new inspiration for the preparation of the highly efficient solar cell.

In this paper, a facial strategy is employed to directly growing ZnO nanorods (ZnONR) on carbon fiber paper (CFP) and functionalizing with silver nanoparticles (AgNP), constructing a structural stable paper-based electrode (AgNP/ZnONR@CFP). This unique AgNP/ZnONR hierarchical nanoarchitecture provides large surface area and an easy substrate penetrable structure facilitating enhanced electrochemical features towards flavonoids oxidation. When the electrode is evaluated as a binder-free sensor for flavonoids detection, three distinct and separate differential pulse voltammetric peaks for luteolin, daidzein, and baicalein are observed, demonstrating the simultaneous and selective detection of these flavonoids possible. The AgNP/ZnONR@CFP sensor demonstrates a remarkable wide linear relationship with low detection limits for luteolin, daidzein, and baicalein detection in a mixed solution. When the sensor is employed to analyze luteolin, daidzein, or baicalein in real extracts from Japanese Honeysuckle, Soybean, and Chrysanthemum morifolium, satisfactory recovery rates (ranging from 96.3 % to 102.5 %) and low relative standard deviation (RSD) values (less than 5.0 %) are obtained. In addition, an assembled sensor device (two-electrode) based on this trimmable AgNP/ZnONR@CFP electrode exhibits remarkable quick response and excellent sensitivity for luteolin, daidzein, or baicalein detection, facilitating real-time and portable detection, highlighting its great potential in batch production of the sensor devices. [Display omitted] • A binder-free electrode is prepared for simultaneous luteolin, daidzein and baicalein detection. • The sensor exhibits high activity with wide linear range and low detection limit. • A two-electrode sensor device is assembled using the AgNP/ZnONR@CFP electrode. • The novel sensor device allows real-time, portable detection and paves the way for mass production. [ABSTRACT FROM AUTHOR]

A new low-temperature facile chemical decomposition of layered double hydroxide (LDH) has been developed for the large-scale controlled synthesis of zinc oxide (ZnO) nanorod on exfoliated graphene oxide (GO) nanosheet. ZnAl-LDH/GO composite precursor was prepared via in situ growth of the LDH on the exfoliated GO nanosheets. Thermo-chemical decomposition of ZnAl-LDH/GO composite at 80 °C produced highly dispersed ZnO nanorods on GO nanosheets. Although, neat ZnAl-LDH produces ZnO nanoparticle aggregates in the absence of GO. The morphology and properties of ZnO nanorods/GO nanocomposite was studied by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The band gap engineering of the nanocomposite was evaluated by varying GO content. The ZnO/GO nanocomposites materials exhibited excellent photo-catalytic activity towards the degradation of methylene blue (MB) and Cr(VI) reduction under the irradiation of direct sunlight at ambient condition. GO plays a crucial role in the directional growth of nanorods and enhances the photocatalytic activity of ZnO nanorods via the synergistic hole formation and electron transfer effect for the potential remediation of waste water. Layered double hydroxide (LDH) derived tailored synthesis of zinc oxide (ZnO) nanorod on exfoliated graphene oxide (GO) via a facile low-temperature chemical decomposition for simultaneous photocatalysis. [Display omitted] • Novel synthesis of LDH derived well defined ZnO nanorods on exfoliated graphene oxide nanosheets. • Exfoliated GO provides active surface for one dimensional growth of ZnO nanorods with aspect ratio 1:8. • The band gap of ZnO/GO nanocomposite decreases with increase in GO content. • Enhanced photocatalytic efficiency in dye degradation and Cr(VI) reduction by ZnO/GO nanocomposite. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnO/Bi 2 MoO 6 /ZIF-67 photocatalyst synthesized and immobilized on FTO. • A planar PFC microreactor for TTC removal was designed. • Tetracycline removal was matched with the Langmuir-Hinslewood kinetic model. • Under optimal conditions: P max = 1.35 mW/cm2, I sc = 4.1 mA/ cm2 was obtained. • The effects of electrolytes in the μPFC system were evaluated. In the Photocatalytic fuel cell microreactor system, a three-component photocatalyst powder of ZnO nanorod/Bi 2 MoO 6 /ZIF-67 was synthesized and deposited as a photoanode immobilize on an FTO substrate using the drop-casting method. The electrochemical properties and photocurrent obtained in the ZnO/Bi 2 MoO 6 /ZIF-67 photoanode/FTO system exceeded those of ZnO/Bi 2 MoO 6 /FTO and ZnO/FTO. The use of the ZnO/Bi 2 MoO 6 /ZIF-67 composite on the FTO substrate led to a reduction in the bandgap energy from 1.74 ev to 1.61 ev. The optimal conditions for tetracycline degradation included a tetracycline concentration of 20 ppm, a pH of 7, light intensity of 7.9 mW/cm2, and a flow rate of 120 µL/min. Under these conditions, the removal efficiency and TOC were calculated as 97.16 % and 92.4 %, respectively. The maximum power density was 35.1 mW/cm2, and the photocurrent density was 1.4 mA/cm2. The kinetics of tetracycline removal in the microreactor input followed the Langmuir-Hinshelwood model, and mass transfer resistance in the fluid phase did not significantly affect the reaction kinetics. Additionally, the time-on-stream (TOS) curve indicated that the removal efficiency dropped below 80 % after 1450 min of operation, reaching a breaking point. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) spectroscopy has attracted increasing attention due to its high spectral reproducibility and unique selectivity to target molecules. Here, a facile approach is proposed to prepare Ag nanoparticles modified ZnO nanorod arrays (Ag/ZnO NR arrays). Ag nanoparticles were densely decorated on the surface of ZnO nanorods through silver mirror reaction and subsequent seed-assisted electrodeposition. The prepared Ag/ZnO NR arrays can be used as a sensitive, uniform, and repeatable SERS substrate for the rapid detection of organic dye molecules and biomolecules with concentrations higher than the corresponding limits of detection (LODs). The LODs for rhodamine 6G (R6G), 4-aminothiophenol (PATP) and adenine are calculated to be 1.0 × 10−13 M, 1.6 × 10−12 M and 3 × 10−11 M, respectively. The enhancement factor (EF) of the SERS substrate is estimated to be as high as ~2.7 × 108 when detecting 10−10 M R6G. Particularly, the as-synthesized substrate exhibits high selectivity to multiple components. In addition, the fabricated Ag/ZnO NR arrays can be recycled due to their superior self-cleaning ability and can realize photocatalytic degradation of R6G in water within 1 h driven by UV light, showing that the three-dimensional recyclable SERS substrates have wide applications in environmental pollution monitoring and biomedical analysis.

A novel flexible non-enzymatic electrochemical glucose sensor was constructed with hexagonal structured ZnO nanorods hydrothermally grown on bendable stainless steel wire sieve (SSWS) electrode. The electrocatalytic capability of the sensor towards glucose was obviously enhanced with ultraviolet (UV) irradiation introduced during the electrochemical measurements. To be specific, UV irradiation promotes the generation of holes in the ZnO nanorods and these holes raise the amount of hydroxyl. Accordingly, more hydroxyl reacts with glucose and further the electron yield of the glucose sensor is notably increased, thus the sensitivity of the glucose sensor is raised from 36.4 μA mM−1 cm−2 to 91.8 μA mM−1 cm−2. The glucose sensor can maintain 60% and 90% of the initial current after being bended 100 times and used 20 times, respectively. Besides, the glucose sensor also exhibits ignorable response towards interfering substances like d -galactose, fructose, urea, uric acid, ascorbic acid, l -phenylalanine, NaCl, and KCl, and can reliably determine glucose concentrations in human serum samples. This method is considered as an effective way to enhance the electrocatalytic capability of other semiconductor-based electrochemical biosensors. [ABSTRACT FROM AUTHOR]

ZnO nanorods grown on the F-doped tin oxide glass by a chemical bath deposition were sensitized by the electrophoretic technique or the conventional soaking method, and the resulting electrodes were applied to photoanodes of dye-sensitized solar cells (DSSCs). The DSSC with an electrophoretically-sensitized ZnO layer showed an increase in both the short-circuit current (Jsc) and the open-circuit voltage (Voc), resulting in a 220% enhancement of photovoltaic performance, when compared to that of the reference cell with a conventionally-sensitized ZnO layer. By applying the electrophoresis to dye adsorption, dye-loading amount was considerably increased, and thereby enhancing the light harvesting efficiency and reducing the interfacial charge recombination between photoinjected electrons and I3−. This led to the enhancement in Jsc and Voc, compared to those of the reference cell. [ABSTRACT FROM AUTHOR]

Recycled valuable energy production by the electrochemical CO2 reduction method has explosively researched using countless amounts of developed electrocatalysts. Herein, we have developed hybrid sandwiched Ga2O3:ZnO/indium/ZnO nanorods (GZO/In/ZnONR) and tested their photoelectrocatalytic CO2 reduction performances. Gas chromatography and nuclear magnetic spectroscopy were employed to examine gas and liquid CO2 reduction products, respectively. Major products were observed to be CO, H2, and formate whose Faradaic efficiencies were highly dependent on the relative amounts of overlayer GZO and In spacer, as well as applied potential and light irradiation. Overall, the present study provides a new strategy of controlling CO2 reduction products by developing a sandwiched hybrid catalyst system for energy and environment.

We report on employing in vitro biosynthesized ZnO nanoparticles using L. pubescens shoot methanol extract (50 and 100 mg LP–ZnO NPs) to examine their antimicrobial efficacy against Pseudomonas aeruginosa (ATCC27853), Staphylococcus aureus (ATCC 29213), Aspergillus niger (ATCC 16404 NA), and Aspergillus terreus (TCC 10029). The formation and stability of the investigated ZnO nanoparticles were proven by transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), UV–vis spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The ZnO nanoparticles were rod-shaped (width: 10.76–30.93 nm). The nanoparticles in dimethyl sulfoxide (DMSO) outperformed their water counterparts in terms of their zones of inhibition (ZIs) (marginal means of 12.5 and 8.19 mm, respectively) and minimum inhibition concentrations (MICs) (means of 4.40 and 8.54 mg/mL, respectively). The ZI means for S. aureus, P. aeruginosa, A. terreus, and A. niger were 10.50, 6.13, 12.5, and 11.5 mm, respectively. When treating S. aureus and P. aeruginosa, the ZI of the 50 mg LP–ZnO NPs in water was better (14 mm), with a lower MIC and lower minimum bactericidal/fungicide concentrations (MBC/MFC) (7.22 and 4.88 mg/mL, respectively) than the ZnO and control drugs. The SEM images showed cellular alterations in the surface shapes after the LP–ZnO-NP treatments. Biosynthesized LP–ZnO NPs could have beneficial antibacterial properties, which could allow for future contributions to the development of new antimicrobial drugs.

Organic synthetic dyes are widely used in several industries; however, their inherent resistance to biodegradation necessitates to investigate alternative methods for the remediation of this class of hazardous substances. In the present study, a green synthesis of ZnO nanorods was achieved in a fast, environment-friendly, and safe microwave process employing algal extract. Different metabolites like sugars, proteins, fatty acids, amino acids, and vitamins present in the algal extract reduced the Zn2+ into ZnO. The XRD analysis showed that the nanostructure was a crystalline hexagonal nanorod having a crystalline size of 27.37 nm. The XPS spectra of ZnO nanorod showed characteristic peaks at binding energy 1043, 1020, 496, 137, 87, and 8 eV corresponding to Zn2p1/2, Zn2p3/2, ZnLMM, Zn3s, Zn3p, Zn3d, respectively. The synthesized ZnO nanorods were in-situ functionalized and showed strong catalytic activity in photoreduction of a model organic dye methylene blue (MB) under direct sunlight irradiation. Synthesized ZnO nanorods showed a complete (100%) reduction of model dye MB from its 10 mg/L aqueous solution. The photocatalytic degradation of MB followed the Michaelis-Menten kinetics. The rate of ZnO-catalyzed photocatalytic degradation depends on the concentrations of ZnO, pH, and sunlight irradiation. The ZnO nanorod-catalyzed photoreduction of MB involves hydroxyl radicals. Algal-mediated and microwave-assisted synthesis provides a scalable source of metal oxide nanoparticles for the remediation of dye-containing wastewaters under natural sunlight. Apart from application in the removal of dyes, ZnO nanorods are excellent material for applications in semiconductors, electronics, optics, bio-imaging, and drug delivery. [ABSTRACT FROM AUTHOR]

Biofilm eradication is a tedious process and can often fall prey to ineffectiveness arising from the continuous usage of different antimicrobials. Hence, there is a burgeoning need to combat biofilms, and nanomaterials can help pave the way. The green synthesis of zinc oxide (ZnO) nanomaterials has multiple inherent facets that perish microbes while being economical, eco-friendly, and non-toxic. The current study is based on enunciating and exploring the impact of green ZnO nanorods (NRs) fabricated via the aqueous seed extract of Cucurbita moschata against Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 10145. The synthesized nanomaterial was characterised via absorbance at 360 nm in UV-VIS spectroscopy, rod-shape by Field Emission Scanning Electron Microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR) analysis demonstrating absorption of phytocompounds, hexagonal wurtzite structure in X-ray diffraction (XRD) analysis, and purity in scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) analysis. This antibacterial activity of the NRs was effective against S. aureus and P. aeruginosa and repressed their cellular growth. It was capable of biofilm disruption, morphological alterations, reduction in nucleic acids, and modifications in the biofilm matrix, as verified by the FTIR analysis on both strains. The biofilm-forming proteins were seen to have a greater binding affinity towards the nanorods compared to the primary phytocompound of the seed extract. This study not only shows the characteristics of biogenically synthesized novel ZnO NRs from Cucurbita moschata seed extract but also indicates the precise mechanism of biofilm eradication and the relative contribution of the phytoextract and nanorods therein. • Synthesis and characterization of ZnO nanorods from Cucurbita moschata seed extract. • Antibacterial and antibiofilm effect of ZnO nanorods against Staphylococcus aureus and Pseudomonas aeruginosa. • Morphological changes in bacterial cells after ZnO nanorod treatment. • Alterations in the biofilm matrix (EPS), and nucleic acid of cells. [ABSTRACT FROM AUTHOR]

The development of short-wavelength light-emitting diodes (LEDs) with high emission efficiency, a fascinating research area, is still necessary because of great scientific interest and practical significance. Here, a graphene plasmon layer treated by oxygen plasma was employed into ZnO nanorod/p-GaN LEDs for a surface plasmon effect. The graphene-decorated heterojunction exhibited an approximately 4-fold improvement of ZnO ultraviolet (UV) electroluminescence (EL) intensity relative to a primitive p-n junction device. Time-resolved spectroscopy and temperature-dependent luminescence measurement indicated that the EL enhancement resulted from the coupling of ZnO excitons with graphene surface plasmons. The current research not only provides an opportunity to construct three-dimensional architecture from a vertical array of one-dimensional nanorods and a two-dimensional graphene layer, but also proposes an effective strategy to improve near-UV emission efficiency in various devices.

Abstract We report on the fabrication of flexible photocatalytic paper comprised of Cu2O and Ag nanoparticle (NP)-decorated ZnO nanorods (NRs) and its application in visible light photodegradation of organic dye. ZnO NRs are first grown on a kraft paper substrate using a hydrothermal method. The NRs are subsequently decorated with Cu2O, Ag, or both NPs formed by photoreduction processes. Scanning electron microscopy and X-ray diffraction analysis confirm the crystallinity of ZnO NRs. Transmission electron microscopy analysis confirms the compositions of the two types of NPs. Four different types of photocatalytic papers with a size of 10 × 10 cm2 are prepared and used to degrade a 10-μM and 100-mL rhodamine B solution. The paper with Cu2O and Ag NP-co-decorated ZnO NRs has the best efficiency with first-order kinetic constants of 0.017 and 0.041 min−1 under the illumination of a halogen lamp and direct sunlight, respectively. The performance of the photocatalytic paper compares well with other substrate-supported ZnO nanocomposite photocatalysts. With the advantages of flexibility, light weight, nontoxicity, low cost, and ease of fabrication, the photocatalytic paper has good potential for visible light photocatalysis.

This work demonstrated a ZnO-coated optical fiber sensor for the detection of a volatile organic compound (VOC) biomarker for diabetes for detecting isopropanol (IPA) markers. A coreless silica fiber (CSF) was connected to a single-mode fiber (SMF) at both ends to achieve a SMF–CSF–SMF structure. CSF is the sensing region where multimode interference (MMI) generates higher light interaction at the interface between the fiber and sensing medium, leading to enhanced sensitivity. Optimization of the CSF length was conducted numerically to attain the highest possible coupling efficiency at the output. Surface functionalization was achieved via hydrothermal growth of ZnO nanorods directly onto the CSF at low temperatures. The optical fiber-based sensor was successfully fabricated and tested with 20%, 40%, 60%, 80%, and 100% of IPA. The sensor response was recorded using an optical spectrometer and analyzed for sensor sensitivity. The fabricated sensor shows the potential to detect isopropanol with the sensitivity of 0.053 nm/%IPA vapor. Further improvement of the sensor sensitivity and selectivity is also proposed for future work.