Diameter Of Zinc Oxide Nanorods Research Articles

Enhancing Dye-Sensitized Solar Cell Performance with Different Sizes of ZnO Nanorods Grown Using Multi-Step Growth

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.

Synthesis of ZnO Nanorods at Very Low Temperatures Using Ultrasonically Pre-Treated Growth Solution

This paper investigates how the pre-treatment of the growth solution with ultrasonic energy affects the annealing temperatures and the growth temperatures of zinc oxide (ZnO) nanorods. The ultrasonic pre-treatment of the growth solution resulted in the successful growth of ZnO nanorods at a very low annealing temperature of 40 °C. The size and density of ZnO nanorods were found to increase proportionally with the increasing duration of pre-ultrasonic treatment, as indicated by characterisations performed with a scanning electron microscope (SEM). At an annealing temperature of 40 °C, coupled with ultrasonic waves, the SEM results showed that ZnO nanorods’ length and diameter increased by 37 and 25%. A similar pattern was also observed at an annealing temperature of 60 and 80 °C, where the length and diameter of ZnO nanorods increased. In addition, the conductivity and acidity of the aqueous solution that had been sonicated were measured. The results showed that solution conductivity and acidity increased as the ultrasonic treatment continued for longer periods. After 3 min of sonication, the final conductivity and acidity of the solutions were found to be 9164 µS/cm and 6.64, respectively. The results also indicated that the ultrasonic pre-treatment of the growth solution increased the zinc nutrient concentration, which would affect the formation of ZnO nanorods. In addition to the ultrasonic effect, the annealing temperature influenced the active nucleation sites essential to the ZnO nanorods’ expansion.

Growth of Nanostructured Zinc Oxide on Flexible Conductive Substrate: A Review

In this paper, a review on the structural and morphological of nanostructured zinc oxide (ZnO) fabricated on flexible conductive substrate, mainly indium tin oxide coated on polyethylene terephthalate (ITO/PET) via various fabrication method is reported. Besides fabrication method, the effect of fabrication condition such as immersion time of ZnO-ITO/PET via hydrothermal method, concentration of modification material of precursor solution via sol-gel method, value of applied cathodic voltage and value of current densities via electrochemical deposition are also discussed. XRD analysis showed that the growth of ZnO-ITO/PET are preferred on (002) or (101) planes. SEM analysis revealed various type of nanostructured ZnO when prepared by sol-gel, spin coating, HWT and hydrothermal method, highlighting ZnO nanorods as the main morphology of ZnO-ITO/PET. The diameter of ZnO nanorods ranges from 10 nm to 830 nm.

Morphology, Structure, and Optical Properties of ZnO nanorods/Eosin-y Grown via Microwave-assisted Hydrothermal Method

Zinc Oxide (ZnO) was a highly attractive semiconductor material because it has a lot of properties such as non-toxic oxide, a friend of the environment, and stability for biological and biomedical applications. ZnO nanoparticle was deposited on the FTO substrates using sol-gel and spin-coating techniques and microwave-assisted hydrothermal methods were used to grow ZnO nanorods (ZNRs) from the seed layer. After that, the surface of ZNRs was modified using organic Eosin-y dye with different concentrations (0.5, 1, and 3) mM to enhance the surface of ZNRs. The XRD patterns of the as-synthesized ZNRs were indicated that the wurtzite hexagonal structure and the diameter of ZNRs will be increased after coated with Eosin-y and the surface becomes rough. The ZNRs/Eosin-y adsorbed more than 50% incident light and the electronic properties of ZNRs/1mM Eosin-y were studied using Photoluminescence (PL) spectrum and the results proved that 1 mM was the optimum concentration of Eosin-y dye that lead to increase the defects which could be enhanced the properties of ZNRs surface.

Zinc oxide nanorod clusters deposited seaweed cellulose sheet for antimicrobial activity

Seaweed cellulose was isolated from green seaweed Ulva fasciata using a common bleaching agent. Sheet containing porous mesh was prepared from the extracted seaweed crystalline cellulose along with zinc oxide (ZnO) nanorod clusters grown over the sheet by single step hydrothermal method. Seaweed cellulose and zinc oxide nanorod clusters deposited seaweed cellulose sheet was characterized by FT-IR, XRD, TGA, and SEM-EDX. Morphology showed that the diameter of zinc oxide nanorods were around 70nm. Zinc oxide nanorod clusters deposited on seaweed cellulose sheet gave remarkable antibacterial activity towards gram-positive (Staphylococcus aureus, Bacillus ceresus, Streptococcus thermophilis) and gram-negative (Escherichia coli, Pseudomonas aeruginous) microbes. Such deposited sheet has potential applications in pharmaceutical, biomedical, food packaging, water treatment and biotechnological industries.

Variation of index of refraction in cobalt doped ZnO nanostructures

One dimensional zinc oxide (ZnO) nanostructures were fabricated using a low temperature chemical bath deposition technique. The ZnO nanorods were doped with cobalt using cobalt nitrate with cobalt concentration varying from 0% to 9%. The scanning electron microscope images of the nanostructures indicate that the diameter of ZnO nanorods increased with the increase in cobalt doping concentration. The optical characterizations of the doped and undoped samples were performed by investigating the variation in the band gap, the Urbach energy, the index of refraction, and the extinction coefficient with cobalt concentration. The dispersion of index of refraction in cobalt doped ZnO nanostructures was modeled based on the Wemple DiDomenico single oscillator model. The interband oscillator energy and the dispersion energy were estimated for different cobalt doped ZnO nanorod samples based on this model.

Controlling Diameter, Length and Characterization of ZnO Nanorods by Simple Hydrothermal Method for Solar Cells

Zinc oxide (ZnO) nanorods have been synthesized by solution processing hydrothermal method in low temperature using the spin coating technique. Zinc acetate dehydrate, Zinc nitrate hexahydrate and hexamethylenetetramine were used as a starting material. The ZnO seed layer was first deposited by spin coated of ethanol zinc acetate dehydrate solution on a glass substrate. ZnO nanorods were grown on the ZnO seed layer from zinc nitrate hexahydrate and hexamethylene-tetramine solution, and their diameters, lengths were controlled by precursor concentration and development time. From UV-Visible spectrometry the optical band gap energy of ZnO nanorods was calculated to be 3.3 eV. The results of X-Ray Diffraction (XRD) showed the highly oriented nature of ZnO nanorods the hardest (002) peak reflects that c-axis elongated nanorods are oriented normal to the glass substrate. The Field Emission Scanning Electron Microscope (FESEM) was employed to measure both of average diameter of ZnO nanorods, Energy Dispersive X-Ray (EDX) is used to identify the elemental present and to determine the element composition in the samples.

Effect of Ga-modified layer on flexible hydrogen sensor using ZnO nanorods decorated by Pd catalysts

Vertically well-aligned zinc oxide (ZnO) nanorods were grown on a low cost, flexible polyimide substrate using an aqueous solution method under various gallium (Ga)-modified ZnO seed layer conditions. This paper reports fabrication and characterization of flexible hydrogen sensors using a modified ZnO template followed by ZnO nanorods (NRs) incorporated with palladium (Pd) catalyst for hydrogen detection at room temperature. We further explored the effect of a modified seed layer on hydrogen gas sensing at various bending states. Experimental results indicate the diameter of ZnO NRs can be controlled on flexible substrates by using a modified seed layer with moderate crystallinity and improved optical properties. All fabricated sensors have high performance with good mechanical flexibility to a curvature angle of 90° at various seed layer conditions. 3%-Ga modified seed layer showed the highest response factor of ∼91% with good repeatability and stability, which were achieved for 1000ppm hydrogen at room temperature; the sensor limit of detection (LOD) was 0.2ppm. For a future hydrogen-based economy, this work can provide the possibility of a versatile route to fabricate flexible hydrogen sensors with controllable sensing area and optimized sensing properties using a simple method.

Fabrication of ZnO nanorods for NO2 sensor applications: Effect of dimensions and electrode position

In this study, zinc oxide (ZnO) nanorods were fabricated by using hydrothermal method and resistive type nitrogen dioxide (NO2) sensing properties of the nanorods were investigated depending on temperature, NO2 concentration, electrode position and the dimension of the nanorods. To produce ZnO seed layer, zinc acetate solution was coated on a glass substrate by using spin-coater. ZnO nanorods were grown by changing concentration of solution at 90°C for 3h onto seed layer coated substrate. ZnO nanorods were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was observed that the diameters of ZnO nanorods were approximately 30nm, 60nm and 120nm depending on solution concentration. For gas sensing measurements, interdigitated Au electrodes were coated on top or bottom of ZnO nanorods by using thermal evaporator. All samples were tested against to NO2 in dry air ambient depending on concentration (100ppb–1ppm) in the temperature range of 25–200°C. The highest sensor response was observed for ZnO nanorods that were 60nm in diameter. The response and recovery times for all sensors decreased with increasing temperature and the sensors were fully recovered above temperature of 100°C.

Farming of ZnO nanorod-arrays via aqueous chemical route for photoelectrochemical solar cell application

A low temperature aqueous chemical route is employed for the synthesis of zinc oxide (ZnO) nanorod arrays onto the soda lime and fluorine-doped tin oxide (FTO) coated glass substrates at various deposition times. Synthesis/farming of ZnO nanorod arrays (ZNRs) consists of the three-step as-ZnO seed forming, ZnO seed sowing followed by ZnO nanorod arrays growing. The length and diameter of ZnO nanorods increased with the reaction time prolonging. The physical, chemical and morphological properties were analyzed by means of X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), photoluminescence (PL), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) respectively. The XRD pattern revealed wurtzite crystal structures of ZNRs, preferentially orienting in the (002) direction. SEM micrographs show that the ZnO nanorods grew up perpendicular to the substrate and their length increases with increase in deposition time. Finally, the photoelectrochemical (PEC) performance of ZNRs thin films were studied. The junction quality factor upon illumination (nl), series and shunt resistance (Rs and Rsh), flat-band-potential (VFB), fill factor (FF) and efficiency (η) have been estimated.

Growth and electron field emission of ZnO nanorods on diamond films

Zinc oxide (ZnO) nanorods grown on chemical vapor deposited diamond films by thermal vapor transport method have been investigated. In the initial growth status, the semi-spherical ZnO nuclei were preferably deposited near the growth steps on the terraces and the boundaries of diamond grains. With increasing the growth time, the [0 0 0 1] orientated ZnO nanorods appeared and further covered the whole diamond film. It is found that the size of diamond grains would determine the diameter of ZnO nanorods. The electron field emission properties of the ZnO nanorods/diamond system have been significantly improved with respect to pure diamond film. The feature of the ZnO nanorods grown on diamond films played an important role in further enhancing the electron field emission performances.

Density-Controlled Electrodeposition Growth of Zinc Oxide Nanorod Arrays

Density-controlled zinc oxide (ZnO) nanorod arrays were synthesized on indium tin oxide (ITO) substrates via a potentiostatic electrodeposition method under different conditions. The effects of preparing conditions on the density of nanorods were systematically investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It is demonstrated that the density and diameter of ZnO nanorods can be effectively controlled by varying the electrodeposition parameters, such as electrodeposition potential, concentration of Zn2+ precursor and growth temperature. Pre-treatment of the substrate also has great influence on the morphology of the electrodeposited ZnO nanorods. By coating the ITO substrates with an gold (Au) or ZnO nanoparticle seed layer, ZnO nanorod arrays with an average diameter of about 50 nm were synthesized, and the nanorod density can be controlled to above 50 x 10(8) rod cm(-2), which is several dozen times greater than that of the ZnO nanorod arrays synthesized on original ITO substrates.

Optical Properties of ZnO Nanorods on Glass Via Spray Deposition of Solution Containing Zinc Chloride and Thiourea

In this research paper, we have investigated optical properties of two zinc oxide (ZnO) nanorods specimens grew on a glass by spray deposition of a solution, which contains only zinc chloride (ZnCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) and ZnCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> with small amount of thiourea (tu: CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S). We sprayed a 1 mL of each solution onto a glass in every minute to obtain a 50 mL specimen. The prepared specimens were characterized by X-ray diffraction, SEM, Fourier transform infrared spectroscopy, UV-Vis absorption spectroscopy, and photoluminescence spectroscopy. We have observed from SEM measurements that small addition of thiourea into a ZnCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> solution (ZnCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> :tu = 1:0.25) provides significantly thinner ZnO nanorods with a higher aspect ratio compared to that obtained from only ZnCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> solution. It is noted that this addition considerably decreased the diameter of ZnO nanorods to 500 nm and increased the height to approximately 200 nm. This is desirable in nanotechnology applications. However, it is observed from PL measurements that optical properties of ZnO nanorods prepared from ZnCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and thiourea solution deteriorate.

Low temperature hydrothermal growth and optical properties of ZnO nanorods

AbstractWell‐faceted hexagonal ZnO nanorods have been synthesized by a simple hydrothermal method at relative low temperature (90°C) without any catalysts or templates. Zinc oxide (ZnO) nanorods were grown in an aqueous solution that contained Zinc chloride (ZnCl2, Aldrich, purity 98%) and ammonia (25%). Most of the ZnO nanorods show the perfect hexagonal cross section and well‐faceted top and side surfaces. The diameter of ZnO nanorods decreased with the reaction time prolonging. The samples have been characterized by X‐ray powder diffraction (XRD) and scanning electron microscopy (SEM) measurement. XRD pattern confirmed that the as‐prepared ZnO was the single‐phase wurtzite structure formation. SEM results showed that the samples were rod textures. The surface‐related optical properties have been investigated by photoluminescence (PL) spectrum and Raman spectrum. Photoluminescence measurements showed each spectrum consists of a weak band ultraviolet (UV) band and a relatively broad visible light emission peak for the samples grown at different time. It has been found that the green emission in Raman measurement may be related to surface states. (© 2009 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

A ZnO nanorod based layered ZnO/64° YX LiNbO 3 SAW hydrogen gas sensor

A zinc oxide (ZnO) nanorod based surface acoustic wave (SAW) sensor has been developed and investigated towards hydrogen (H 2) gas. The ZnO nanorods were deposited onto a layered ZnO/64° YX LiNbO 3 substrate using a liquid solution method. Micro-characterization results revealed that the diameters of ZnO nanorods are around 100 and 40 nm on LiNbO 3 and Au (metallization for electrodes), respectively. The sensor was exposed to different concentrations of H 2 in synthetic air at operating temperatures between 200 °C and 300 °C. The study showed that the sensor responded with highest frequency shift at 265 °C. At this temperature, stable baseline and fast response and recovery were observed.