Optical Properties Of ZnO Nanoparticles Research Articles

A study on structural and optical properties of the synthesized PVP capped Zinc Oxide Nanoparticles

Zinc Oxide Nanoparticles, capped with a polymer, have been effectively synthesized using a chemical precipitation method at a relatively low reaction temperature of 60 °C. The present study examines the structural and optical properties of ZnO Nanoparticles (NPs) that have been synthesized and capped with different weight percentages of PVP (Polyvinyl Pyrrolidone). To investigate these properties, advanced analytical techniques including X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Ultra Violet-visible (UV–vis) absorption spectroscopy are employed. The XRD analysis reveals that the synthesized ZnO samples have a hexagonal wurzite structure, regardless of adding capping agent. The Williamson-Hall (W-H) analysis, a commonly used method, estimates the strain present in synthesized materials. The SEM image depicts ZnO NPs that have a nearly spherical form and are seen to be agglomerated. The UV–vis absorption measurements demonstrate a phenomenon known as blue shift when compared to the absorption characteristic of bulk ZnO.

Insights into Structural and Optical Properties of ZnO Nanoparticles

Insights into Structural and Optical Properties of ZnO Nanoparticles

Tuning of structural, magnetic, and optical properties of ZnO nanoparticles by Co and Cu doping

Undoped, Cu, and Co-doped ZnO nanoparticles were synthesized by a simple co-precipitation method. We studied the structural, chemical, magnetic, and optical properties of synthesized nanoparticles by using X-ray Diffraction, Fourier Transform Infrared, Scanning Electron Microscopy, Vibrating-Sample Magnetometer, and UV–VIS spectroscopy. The X-ray Diffraction analysis discovers the crystalline hexagonal wurtzite structure and confirms the incorporation of Cu2+ and Co2+ in the ZnO lattice. The SEM photographs show that the nanoparticles are agglomerated, and the grain size of pure ZnO is decreased upon doping, showing inhibition of grain growth through doping. From VSM the coercivity and saturation magnetization of Co-doped (0.0189 emu/g and 84.044Oe) is higher as compared to pure and Cu-doped ZnO. The energy gap of doped and un-doped nanoparticles determined from the absorption spectrum indicates that it increases by doping of Copper and cobalt.

Magnetic and optical properties of ZnO nanoparticles and nanorods synthesized by green chemistry

ZnO nanostructures have attracted considerable attention because of their physicochemical properties and applications as antibacterial agents, photocatalytic reactions for pollutant removal, and electronics. Hence, efficient production and knowledge of their properties under different synthesis conditions are essential. Biosynthesis has emerged as an excellent growth-directing method for synthesizing nanomaterials, representing a soft and cleaner alternative for their production. In this study, we synthesized different ZnO nanostructures using a soft chemistry method at different growth temperatures, from 200 to 800 °C every 200 °C. The crystalline structure was estudied by x-ray Diffraction (XRD) and High-Resolution Transmission Electron Microscopy (HRTEM). The shape and size were studied by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM), which revealed a ZnO hexagonal phase with two shapes: nanoparticles (NPs) with irregular shapes and nanorods of different sizes. The optical properties were studied by Raman and UV-visible spectroscopy, and optical absorption measurements showed bandgap tuning of the produced nanostructures. Finally, the magnetic characteristics of the samples demonstrated magnetic anisotropy due to the preference for crystalline formation and the size of the nanoparticles. The magnetic interaction between the two types of NPs increased the diamagnetism associated with the nanorods.

Antibacterial Activity of Prepared Zinc Oxide Nanoparticles by Eco-Friendly Method Using Olive Leaves and Roselle Flower Extracts

This research looked at the antimicrobial properties of zinc oxide nanoparticles (ZnO NPs) made from roselle flower extracts and olive leaves as part of a green synthesis method. We used field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet-visible (UV–vis) spectroscopy and Fourier-transform infrared (FTIR) spectroscopy to study the morphological, structure and optical properties of ZnO NPs. The Field Emission Scanning Electron Microscopy (FESEM) test revealed that the ZnO NPs (Olive leaves) had round particles with sizes ranging from 29.03[Formula: see text]nm to 53.59[Formula: see text]nm, while the ZnO NPs (Roselle flower) had nanoflakes with sizes ranging from 42[Formula: see text]nm to 80[Formula: see text]nm. By using UV–vis spectroscopy, it was found that the optical energy gap for ZnO NPs derived from olive leaves was about 2[Formula: see text]eV and for ZnO NPs derived from rose flowers it was 2.2[Formula: see text]eV. The antimicrobial properties of ZnO nanoparticles (NPs) were assessed against two types of bacteria: gram-negative bacteria (Klebsiella pneumoniae) and gram-positive bacteria Staphylococcus aureus (S. aureus). Both plant extracts exhibited a maximal inhibitory zone of 21[Formula: see text]mm against gram-positive bacteria, specifically S. aureus.

Exploring the synergistic influence of Cu and Co co-doping on the optical properties of ZnO nanoparticles

In this study, we synthesized Cu and Co co-doped ZnO nanoparticles, denoted as Zn1-2xCuxCoxO (x = 0.01, 0.02, 0.03), using the sol-gel auto-combustion method. Successful integration of Cu and Co elements into the ZnO host lattice was confirmed through a comprehensive array of spectroscopic techniques. Structural analysis revealed the persistence of a hexagonal wurtzite crystal structure with some distinct microstructural variations across all samples. Alteration in lattice parameters and dislocation density strongly suggests the successful incorporation of Cu2+ and Co2+ ions within the ZnO lattice. A prominent increase in crystallite size from 27.19 nm to 33.46 nm was observed with the increase in doping concentration. Field emission scanning electron microscopy showed a combination of uniformly distributed spherical and hexagon-like structures. Furthermore, UV–Visible absorption spectra demonstrated a proportional enhancement in energy band gap from 2.14 eV for Zn0.98Cu0.01Co0.01O to 2.40 eV for Zn0.94Cu0.03Co0.03O. The Burstein−Moss effect was invoked to elucidate the observed blue shift in absorption spectra and energy band gaps, further solidifying our findings. The systematic and substantial correlation between dopant concentration and energy band gap signifies that the co-doping of Cu and Co is a viable strategy for engineering the band gap of ZnO. This collective investigation unveils the substantial potential of Cu and Co co-doping in ZnO nanoparticles for advanced optoelectronic applications, paving the way for tailored optical and photonic functionalities.

Effect of reduced graphene oxide on the structural and optical properties of ZnO nanoparticles

The co-precipitation method was used to synthesize ZnO nanoparticles (NPs). Then, graphene oxide (GO) sheets which were reduced during the reaction process to become (rGO), were embellished with ZnO NPs. The impact of rGO on the structure and morphology of ZnO was investigated using XRD, FTIR, TEM, and SEM techniques. Investigating the optical characteristics was done using UV–vis spectroscopy. ZnO exhibits a hexagonal phase, as proved by XRD. The average crystallite size reduced from 22 to 18 nm after being anchored on rGO sheets. TEM and SEM testify to the presence of ZnO in nanoscales with quasi-spherical shapes, which dispersed homogeneously along the GO sheets. The optical bandgap was increased from 2.57 eV to 3.17 eV for ZnO and ZnO-rGO, respectively. Based on the obtained optical bandgap, the refractive index of ZnO and ZnO-rGO nanocomposite was theoretically determined using different models such as Moss and Ravindra models. ZnO-rGO nanocomposite's ability to change optical characteristics makes it a superior nominee for optoelectronic applications.

Green Fabrication and Characterization of Zinc Oxide Nanoparticles using Eucalyptus Leaves for Removing Acid Black 210 Dye from an Aqueous Medium

This study uses an environmentally friendly and low-cost synthesis method to manufacture zinc oxide nanoparticles (ZnO NPs) by using zinc sulfate. Eucalyptus leaf extract is an effective chelating and capping agent for synthesizing ZnO NPs. The structure, morphology, thermal behavior, chemical composition, and optical properties of ZnO nanoparticles were studied utilizing FT-IR, FE-SEM, EDAX, AFM, and Zeta potential analysis. The FE-SEM pictures confirmed that the ZnO NPs with a size range of (22-37) nm were crystalline and spherical. Two methods were used to prepare ZnO NPs. The first method involved calcining the resulting ZnO NPs, while the second method did not. The prepared ZnO NPs were used as adsorbents for removing acid black 210 dye (AB210) from simulated wastewater. The removal efficiency using calcinated and uncalcinated ZnO NPs was 57 % and 59 %, respectively.

Structure based photocatalytic efficiency and optical properties of ZnO nanoparticles modified by annealing including Williamson-Hall microstructural investigation

Structural deficiency in annealed ZnO nanoparticles would be a critical concern for the optical properties and photocatalysis efficiency of ZnO. Therefore, the structure and microstructure of synthesized ZnO nanoparticles annealed at 500 °C, 700 °C, and 900 °C for 4 h have been analyzed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and UV–visible Diffuse Reflectance Spectroscopic (UV–Vis DRS) techniques. Williamson-Hall and modified Williamson-Hall models have explored microstructural properties. The bandgap in ZnO decreases from 3.18 eV to 3.11 eV for annealing, which coincides with the assessed optical band edge approximately and the accumulation of particles observed from SEM images. Moreover, the redox potential has been calculated for annealed samples to perform the photocatalytic experiment. Additionally, the photocatalytic performance has been estimated from the degradation of UV irradiation through the studied samples. Finally, the sample ZnO annealed at 500 °C confirms maximum RhB degradation rate of 60.9% due to its lower particle size with a higher surface area. The ZnO-500 may be a potential photocatalyst material, including semiconducting properties.

Normality Effect on Characterization of Chemically Synthesized ZnO Nanoparticles

The current research activities that focus on the preparation of ZnO nanostructure material and their physical and optical properties characterization. ZnO nanoparticles were synthesized using sol-gel chemical precipitation technique with zinc acetate and sodium hydroxide in distil water as a starting materials. Stock solutions of zinc acetate and sodium hydroxide at different normality (0.10N, 0.25N, 0.50N, 0.75N and 1N) were used for preparation of ZnO‘s. Synthesized sample of ZnO precipitate was dried at ordinary temperature for 12 hours and calcinied at 1000C for 2 hours and were physically characterized by using XRD (X-ray diffraction), SEM (scanning electron microscope) and FTIR spectroscopy. The XRD spectra exhibit wurtzite hexagonal crystal structure. The particle size statistically estimated from XRD data show that the ZnO samples consist of nanosize particles. The optical properties of ZnO nanoparticles was studied by using UV-visible absorption and PL (photoluminescence ). The effect of normality of different precursors used in preparation of ZnO nanoparticles, on spectroscopic characterizations was investigated. UV-Visible spectra give blue luminescence near band edge. PL exhibits green luminescence that suggest surface defect due to oxygen vacancies effect in ZnO nanoparticles.

Millettia Pinnata leaves extract mediated ZnO nanoparticles and their antimicrobial, cytotoxicity study

Synthesizing ZnO nanoparticles for their antibacterial and cytotoxic properties is performed using a green concept in this study. Millettia Pinnata leaf extract was used to reduce zinc acetate to prepare ZnO nanoparticles. Due to the high concentration of biomolecules (flavonoids, alkaloids etc.,), Millettia Pinnata leaf extract produces stable ZnO nanoparticles. The structural and optical properties of ZnO nanoparticles have been investigated using UV–visible spectroscopy, X-ray diffraction spectroscopy, Fourier-transfer infrared spectroscopy, scanning electron microscopy, and X-ray energy dispersive spectroscopy. The prepared ZnO nanoparticles are spherical, have a hexagonal crystal phase, and are relatively stable. ZnO nanoparticles were tested for antibacterial and antifungal properties against Bacillus globigii, Escherichia coli and Aspergillus niger. The MTT assay measured the cytotoxic activity against the human breast cancer (MCF-7) cell lines. Its environmentally friendly properties suggest that the synthesized ZnO nanoparticles may be used in a wide variety of environmental remediation applications due to their antibacterial, antifungal, and anticancer properties.

Significance of Hydroxyl Groups on the Optical Properties of ZnO Nanoparticles Combined with CNT and PEDOT:PSS.

We report on the synthesis of ZnO nanoparticles and their hybrids consisting of carbon nanotubes (CNT) and polystyrene sulfonate (PEDOT:PSS). A non-aqueous sol–gel route along with hydrated and anhydrous acetate precursors were selected for their syntheses. Transmission electron microscopy (TEM) studies revealed their spherical shape with an average size of 5 nm. TEM also confirmed the successful synthesis of ZnO-CNT and ZnO-PEDOT:PSS hybrid nanocomposites. In fact, the choice of precursors has a direct influence on the chemical and optical properties of the ZnO-based nanomaterials. The ZnO nanoparticles prepared with anhydrous acetate precursor contained a high amount of oxygen vacancies, which tend to degrade the polymer macromolecule, as confirmed from X-ray photoelectron spectroscopy and Raman spectroscopy. Furthermore, a relative increase in hydroxyl functional groups in the ZnO-CNT samples was observed. These functional groups were instrumental in the successful decoration of CNT and in producing the defect-related photoluminescence emission in ZnO-CNT.

Eco-friendly Green Synthesis of stable ZnO nanoparticles using citrus limon: X-Ray Diffraction Analysis and Optical Properties

Eco-friendly stable ZnO nanoparticles (NPs) were synthesized by sol-gel method using citrus limon as a chelating agent. The structural analysis and optical properties of ZnO NPs annealed in air ambient at different temperatures ranging from 600 to 900 °C are reported. A detailed x-ray diffraction (XRD) analysis of ZnO NPs has been discussed. Morphological and optical properties of the NPs were investigated using Field Emission Scanning Electron Microscopy (FE-SEM), XRD, Diffuse Reflectance Spectroscopy (DRS), Photoluminescence (PL), Fourier Transform Infrared spectroscopy (FTIR) and Raman Spectroscopy techniques. The FE-SEM reveals that the average particle size of ZnO NPs increased from 62 to 77 nm due to agglomeration of particles or Ostwald ripening which usually happens at high temperature. Physical and microstructural properties such as crystallite size, strain, stress and dislocation density of ZnO NPs were obtained from XRD spectra studies and compared the estimated parameters by various models. It is observed that, the crystallite size increased after annealing and the strain present in NPs is due to defects. Kubelka-Munk function is used to obtain bandgap of NPs from DRS spectra. A slight decrease in the bandgap of ZnO NPs is due to the increase in particle size. PL spectra reveals that the emission around 402 nm near the UV region is attributed to the near band edge emission (NBE) and emission peaks in a visible region is due to the transition of electrons from traps in bandgap to the valence band.

Synthesis and characterizations of phosphorus doped ZnO nanoparticles

We reported the synthesis of phosphorus doped ZnO nanoparticles for a concentration of P ranging from 2 to 8%by a sol–gel processing technique. The structural and optical properties of these nanoparticles were characterised by different techniques. The structural study confirms the presence of hexagonal wurtzite phase with average crystallite size around 30nm. However, the optical study was shown a high absorption in the UV range and an important reflectance in the visible range. The optical band gap of P-ZnO samples were varied between 3.32 and 3.28 eV. The aim of this work is to study the effect of phosphorus doping on the structural, morphological and optical properties of ZnO nanoparticles.

Ni doping effect on the electronic, structural and optical properties of ZnO nanoparticles prepared by Co-precipitation route

Nanoparticles (NPs) synthesized by the co-precipitation technique show many attractive properties such as small particle size, high crystallinity, high average pore diameter and high specific surface area. However, numerous reports show that some characteristics of the Ni-doped ZnO (NZO) NPs remain controversial such as optical bandgap (Eg), surface morphology and defect level. In this study, pure ZnO and NZO NPs at different Ni contents (x) were successfully prepared using the co-precipitation method. Phase analysis confirms the hexagonal wurtzite crystallinity of the samples. XRD peak shows that the Ni may substituted ZnO structure as the peaks shift toward higher angles with increasing x. Meanwhile, the formation of NiO secondary phases was significant at 12.50% Ni content. Densely packed spherical shaped structures with nanoparticle agglomeration are observed at low x, while some nanorod shaped structures appear at higher x. The stretching vibrations of the Zn–O bond are observed in the NZO NPs. The absorption edge shifts to higher wavelengths with the increase in x. This study provides consistent results in the phase analysis, morphology and structural parameters. The decrease in Eg agrees with the photoluminescence measurements. The emission spectra confirm the presence of interstitial zinc and singly ionized oxygen vacancies.

Size-dependent spectroscopic insight into the steady-state and time-resolved optical properties of ZnO photocatalysts

In this paper, we present a spectroscopic insight into the structural and optical properties of ZnO nanoparticles (NPs) applied for water depollution using the photocatalytic process. Samples of various sizes and shapes were synthesized using simple, cost-effective chemical methods. The steady-state optical properties were analyzed using absorption and fluorescence emission spectroscopy and the band-gap and emission energies revealed an inverse dependence on the ZnO particles size. The time-resolved fluorescence properties were studied using time-correlated single photon counting (TCSPC) technique. Three emissive states were identified for all ZnO samples, with lifetimes that showed an overall decrease with increasing the particles diameter. The insights into the photocatalytic process toward understanding the ZnO nanoparticles mediated photocatalysis for degradation of Rhodamine (RhB) and oxytetracycline (OTC) was elucidated. The increase of photocatalytic activity was due to charge carrier partition and mobility.

Structure Based Photocatalytic Efficiency and Optical Properties of Zno Nanoparticles Modified by Annealing Including Williamson-Hall Microstructural Investigation

Structure Based Photocatalytic Efficiency and Optical Properties of Zno Nanoparticles Modified by Annealing Including Williamson-Hall Microstructural Investigation

(Ni, Al) co-doping influence on structural and optical properties of ZnO nanoparticles synthesized via co precipitation method

(Ni, Al) co-doping influence on structural and optical properties of ZnO nanoparticles synthesized via co precipitation method

Synthesis, Characterization and Optical Properties of ZnO Nanoparticles Doped with Er and Yb.

This paper discusses the structure, particle morphology, and optical properties of un-doped ZnO and ZnO doped with Er3+ and Yb3+ lanthanide ion nanoparticles (NPs) through a process denominated sol-gel-hydrothermal. According to the pattern of X-ray diffraction, ZnO:Er and ZnO:Yb is formed by a single-phase wurtzite structure with crystallites sized ~65 nm on average, and Er or Yb dopant ions in the hexagonal structure of ZnO, specifically in its distorted lattice sites. The results also suggest the possible role of oxygen vacancies or Ox- (defects) in the energy transfer from ZnO to the Er or Yb ions with a decrease of 3.18 eV and 3.19 eV in bandgap values to a red shift.

Enhancing structural and optical properties of ZnO nanoparticles induced by the double co-doping of iron and cobalt

The (Fe,Co) codoped ZnO nanoparticles were synthesized through PEG assisted route and characterized by XRD,UV visible and SEM with EDAX analysis. The structural analysis shows that the synthesized nanoparticles have crystalline nature and the crystallite size is found to be 49.43 nm. The UV visible spectrum shows that the energy band gap of synthesized nanoparticles was found to be 2.9 eV. The structural morphology was found by SEM analysis and the synthesized sample forms a cluster structure. The presence of Fe, Co and ZnO were confirmed by EDAX analysis. This promotes its utilization in optoelectronic devices.