Size Of ZnO Nanorods Research Articles

Enhancing the interfacial strength of jute fiber/polylactic acid composites via surface carboxymethylation pretreatment and in situ growth of ZnO nanorods

ABSTRACT Jute fibers (JFs) are considered an excellent reinforcement due to their abundant resources, environmental friendliness, low cost, lightweight, high specific strength and high specific modulus. However, they still suffer from surface defects that result in poor interfacial compatibility with polymeric matrices. This paper proposes a novel strategy that combines carboxymethylation pretreatment of JFs with in situ growth of ZnO nanorods (NRs) to enhance the mechanical properties of JFs and interfacial properties of JFs/polylactic acid (PLA) composites. The results indicate that carboxymethylation is a more effective method for removing pectin from the surface of JFs compared to conventional acid/alkali treatment. Subsequently, ZnO NRs are deposited in situ on the surface of carboxymethylation-treated JFs (c-JFs) through a seed-growth process, resulting in ZnO NRs@c-JFs. The impact of diverse process parameters, namely reaction time (t), reaction temperature (T) and concentration of zinc source (C), on the morphology and size of ZnO NRs was thoroughly investigated. Optimal process conditions were determined to be t = 6 h, T = 95°C, and C = 37.5 mmol·L−1, resulting in well-aligned ZnO NRs that completely filled up the grooves on JFs’ surface. Compared to untreated JFs, the tensile strength and tensile modulus of ZnO NRs@c-JFs increased by 30.4% and 81.6%, respectively, while exhibiting lower hygroscopicity and higher thermal stability. Furthermore, JFs-reinforced PLA composites were fabricated via hot pressing and their interfacial strength was evaluated using a microdroplet debonding test. Compared to untreated JFs/PLA, the combination of carboxymethylation and ZnO growth in ZnO NRs@c-JFs/PLA resulted in a significant 334% increase in interfacial shear strength (IFSS), indicating highly improved interface bonding between JFs and PLA resin, which was primarily attributed to the formation of a ‘zipper-like’ mechanical interlocking structure between ZnO NRs and PLA. This study provides valuable guidance for enhancing the interface of natural fiber/polymer composites and highlights their potential applications.

Acoustofluidic bubble-driven micromixers for the rational engineering of multifunctional ZnO nanoarray

Acoustofluidics that combines acoustics with microfluidics represents an emerging and promising technology for the efficient mixing of fluids and synthesis of functional nanomaterials. However, it remains a great challenge to the controllable synthesis of three-dimensional functional nanostructures in a confined space. Herein, we introduce a robust acoustofluidic bubble-driven micromixer for the controllable synthesis of functional nanoarray inside the glass capillary toward efficient photodegradation and metal ion enrichment. The acoustofluidic micromixer functions with microbubbles-induced acoustic streaming from arrow-patterned microchannels. The morphology, density, and size of ZnO nanorods and nanosheets array can be precisely adjusted by reactant type, seeding phase, and reaction time. ZnO nanorod array exhibits approximately 90% degradation efficiency of R6G even after ten cycles, which are significantly better than ZnO nanosheet array and blank control groups. Enrichment tests of heavy metal ions show that ZnO nanoarray performs better enrichment performance of Cu2+ than that of Ag+. In addition, both photodegradation and enrichment capabilities can be well regulated by tuning the flow rates (i.e., the residence time). These findings provide important guidelines for the rational design of functional nanomaterials and shed new light on the fabrication of advanced lab-on-a-chip devices.

Simultaneous acquisition of current and lateral force signals during AFM for characterising the piezoelectric and triboelectric effects of ZnO nanorods

Atomic force microscopy (AFM) is central to investigating the piezoelectric potentials of one-dimensional nanomaterials. The AFM probe is used to deflect individual piezoelectric nanorods and to measure the resultant current. However, the torsion data of AFM probes have not been exploited to elucidate the relationship between the applied mechanical force and resultant current. In this study, the effect of the size of ZnO nanorods on the efficiency of conversion of the applied mechanical force into current was investigated by simultaneously acquiring the conductive AFM and lateral force microscopy signals. The conversion efficiency was calculated based on linear regression analysis of the scatter plot of the data. This method is suitable for determining the conversion efficiencies of all types of freestanding piezoelectric nanomaterials grown under different conditions. A pixel-wise comparison of the current and lateral force images elucidated the mechanism of current generation from dense arrays of ZnO nanorods. The current signals generated from the ZnO nanorods by the AFM probe originated from the piezoelectric and triboelectric effects. The current signals contributed by the triboelectric effect were alleviated by using an AFM probe with a smaller spring constant and reducing the normal force.

Fundamental Research on Electronic Image Recognition of Cylindrical Zno Nanorods Based on Deep Learning

ZnO is recognized as one of the most important photonic materials in the blue-violet region due to its straight-width band gap and large excitation bonding energy. Since ZnO nanorod array performs superior optical and field emission properties, a lot of efforts have been made in the fabrication of a vertically ordered ZnO nanorod array. The shape and size of ZnO nanorods have a significant effect on PEC property. In order to efficiently recognize and measure the shape and size of ZnO nanorods, a new method based on deep learning model mask r-cnn is proposed to detect cylindrical ZnO nanorods. The SEM images of ZnO nanorods were used as a data set for training. Adjust the size of the bounding boxes that model generated to make it more suitable for the data set. At the same time, improve the NMS (non-maximum suppression) algorithm to reduce the missing detection rate, and achieve a good detection effect on the SEM images of ZnO nanorods.

Fabrication of Graphene-Supported Palladium Nanoparticles-Decorated Zinc Oxide Nanorods for Potential Application

We report the facile synthesis of graphene-supported palladium (Pd) nanoparticles anchored zinc oxide nanorods (Pd-ZnO/G) by the sol-gel method. X-ray diffraction (XRD) pattern confirmed the hexagonal wurtzite crystal structure (with P63mc phase) of Pd-ZnO/G nanorods similar to ZnO structure. X-ray diffraction results showed that graphene-supported Pd nanoparticles anchored on ZnO nanorods increases the average crystallite size of ZnO nanorods. Field emission scanning electron microscopy (FESEM) revealed the successful anchoring of Pd nanoparticles on the surface of ZnO/G nanorods. X-ray spectroscopy (XPS) was used to obtain the different oxidation state and surface compositional details of nanorods. Energy dispersive spectroscopy analysis confirmed the presence of palladium, carbon, and oxygen in Pd-ZnO/G structure. The optical absorption measurement indicates that after graphene and palladium doping, it shifted towards the low wavelength region for Pd-ZnO/G structure and high wavelength region in the case of ZnO/G nanostructure. Magnetic measurement showed that the saturation magnetization of Pd nanoparticles anchored nanorods increased when compared with that of ZnO/G and ZnO nanorods.

Enhancement of external quantum efficiency and quality of heterojunction white LEDs by varying the size of ZnO nanorods

The size of ZnO nanorods (NRs) plays an important role in tuning the external quantum efficiency (EQE) and quality of light generated by white light emitting diodes (LEDs). In this work, we report on the enhancement of EQE and the quality of ZnO NR-based hetrojunction white LEDs fabricated on a p-GaN substrate using a low temperature solution method. Cathodoluminescence spectra demonstrate that ultraviolet (UV) emission decreases and visible deep band emission increases with an increase in the length of the ZnO NRs. The UV emission could be internally reabsorbed by the ZnO NR excitation, thus enhancing the emission intensity of the visible deep band. Photocurrent measurements validated the fact that the EQE depends on the size of ZnO NRs, increasing by 87% with an increase in the length of the ZnO NRs. Furthermore, the quality of white light was measured and clearly indicated an increase in the color rendering indices of the LEDs with an increase in the length of the ZnO NRs, confirming that the quality of light generated by LEDs can be tuned by varying the length of the ZnO NRs. These results suggest that the EQE and visible deep band emission from n-ZnONRs/p-GaN heterojunction LEDs can be effectively controlled by adjusting the length of the ZnO NRs, which can be useful for realizing tunable white LEDs.

The simple fabrication of nanorods mass production for the dye-sensitized solar cell

ZnO nanorods were successfully synthesized by the plasma torch with the zinc powder as the source of ZnO. Several testing was conducted to examine the results of ZnO nanoparticles among others are X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM), and X-ray diffraction (XRD). The results of ZnO nanorods diameter vary from 87 nm to 263 nm which can be seen from SEM images and it is length varies from 300 to 1000 nm. It was found from XRD data that a sharp peak occured at 36.253°. It is indicated a good crystal growth and agreed well with the standard data (JCPDF-ICDD card no.: 36-1451). Effects of electrical current variations of plasma torch of 20, 25, and 30 Amperes on the size of ZnO nanorods are indicated from aspect ratio (72.85, 87.42, and 103 nm). The effects of electrical current of plasma torch on the purity of ZnO were about 95.61%, 98.46%, and 96.49% respectively. The performance of the solar cell at the time with the values of Voc, Jsc, FF, and efficiency are 0.466 V, 1.524 mA/cm 2 ,, 51.95%, and 0.37% respectively. ZnO nanorods were successfully synthesized by the plasma torch with the zinc powder as the source of ZnO.

Size effect of ZnO nanorods on physicochemical properties of plasticized starch composites

This work demonstrates that the size of ZnO nanorods (ZnONR) with similar aspect ratio determines several physicochemical and microbiological properties of thermoplastic starch composites (TPS/ZnONR) at a given concentration of ZnONRs. A combination of sol-gel and hydrothermal methods was developed to synthesize ZnONR with different sizes but similar aspect ratios. Starch composites containing 1wt.% of ZnONR were prepared by casting. Composites with smaller size nanorods (ZnONR-S) showed more efficiency in shielding UVA radiation and had a higher solubility and water vapor permeability than those with larger nanorods (ZnONR-L). Mechanical properties, biodegradability and antibacterial activity were also influenced by the size of the ZnONR. X-ray diffraction analysis showed that composites with ZnONR-S maintained the typical B-V type starch structure, intensifying the V-type starch structure peaks, while composite with ZnONR-L induced the formation of an amorphous structure, preventing starch retrogradation during storage. Properties affected by nanorods size are fundamental in determining composite applications.

Study on the effect of HMTA and ZnO seed layer on the morphology of ZnO nanorods synthesized by electrochemical method

In this paper we investigated the effect of Hexamethylenetetramine (HMTA, C6H12N4) concentration on the growth of ZnO nanorods on ITO substrates and the influence of the ZnO seed layer on its orientation growth. ZnO nanorods were synthesized by the two-step method of stable flow electrochemical method of saline solution Zn(NO3)2 at 90oC. As result, the high hexagonal crystalline ZnO nanorods were well oriented according to the (002) lattice network. The change of amperage and electrolysis time have show the effetive control of morphology and size of ZnO nanorods which has been studied by XRD and SEM images

Fabrication of pit-structured ZnO nanorods and their enhanced photocatalytic performance

ZnO nanorods have been successfully prepared at low temperature (60 °C) in the presence of ammonia via a simple aqueous solution-based chemical approach. After calcination at 300 °C, many unique pitted structures are found on the surface of ZnO nanorods, although the shape and size of ZnO nanorods have almost no changes. Furthermore, the pit-structured ZnO nanorods exhibit higher photocatalytic activity for methylene blue photodegradation with a rate constant (k) of 0.01402 min−1, which is about 3 times more than that of uncalcined sample. The formation of the pitted structures is presumably attributed to the decomposition of a trace amount of ZnO(NH3)n complex implanted into ZnO crystals. In addition, a photocatalytic mechanism is proposed to explain the enhanced photocatalytic activity of the pit-structured ZnO nanorods.

Synthesis of ZnO nanorods on porous silicon substrate using sol–gel method

In this study, the authors have synthesised ZnO nanorods on porous silicon (PSi) substrate using sol–gel method. A simple method to synthesise the ZnO nanorods from aqueous solution that contains zinc nitrate hexahydrate [Zn(NO3)2.6H2O] and hexamethylenetetramine (C6H12N4) is presented. The surface morphology and photoluminescence properties of the samples were characterised using scanning electron microscope (SEM) and photoluminescence spectroscope (PL). The SEM images showed that the size of ZnO nanorods increased with the molar ratio of precursor. Photoluminescence measurements showed that ZnO nanorods exhibit a strong ultraviolet (UV) emission of 397 nm and several weak emissions in the blue and green bands.

Preparation and surface modification of uniform ZnO nanorods via a one-step process

Hydrophobic ZnO uniform nanorods were successfully produced via a one-step process through precipitation transformation reaction in aqueous solution of ZnSO 4, Na 2CO 3 and NaOH with sodium oleate (C 17H 33COONa) as a modifying agent. Sodium oleate was used to control the size and modify the surface property of the nanorods produced from the precipitation transformation reaction. Measurements of relative contact angle and active ratio indicated that ZnO nanorods were hydrophobic. Scanning electron microscope, X-ray diffraction, XPS analysis, and thermogravimetric analysis were applied. These results suggested that the hydrophobic property was attributed to the presence of a thin layer of zinc oleate, which was bonded onto the surface of ZnO nanorods during the reaction process. The effect of surface modification on morphology, and size of ZnO nanorods and the mechanism of surface modification were preliminary presented. This work provided an approach to control the uniform growth of ZnO nanorods and enhance interfacial compatibility between ZnO powders and organic matrixes by treating the surface with certain capping molecules.

Buffer layer effect on ZnO nanorods growth alignment

Vertical aligned ZnO nanorods array was fabricated on Si with introducing a ZnO thin film as a buffer layer. Two different nucleation mechanisms were found in growth process. With using Au catalyst, Zn vapor could diffuse into Au nanoclusters with forming a solid solution. Then the ZnO nucleation site is mainly on the catalyst by oxidation of Au/Zn alloy. Without catalyst, nucleation could occur directly on the surface of buffer layer by homoepitaxy. The density and the size of ZnO nanorods could be governed by morphological character of catalyst and buffer layer. The nanorods growth is followed by vapor–solid mechanism.