INVESTIGATIONS ON STRUCTURAL, DIELECTRIC AND OPTICAL PROPERTIES OF Cu-DOPED ZnO NANOPARTICLES (original) (raw)
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Structural and Optical Properties of Cu Doped ZnO Nanoparticles
In this paper, different characterization techniques are employed to study the effects of copper doping on the structural and optical properties of zinc oxide (ZnO) nanoparticles synthesized by solvothermal method using domestic microwave oven. The X-Ray Diffraction (XRD) pattern indicates that the synthesized samples have a single phase wurtzite hexagonal structure of ZnO. The particle size calculated using Debye Scherrer’s formula is also confirmed by Transmission Electron Microscope (TEM) studies. Scanning Electron Microscope (SEM) studies confirm uniform distribution of the samples and the elements present in the samples have been recorded by Electron Diffraction X-Ray (EDX) spectroscopy. The functional group of the samples has been confirmed by Fourier Transform Infra-Red (FTIR) analysis. UV-Visible (UV-Vis) spectrum shows a red shift in the absorption edge due to the incorporation of Cu2+ ions into ZnO lattice. A weak ultraviolet peak related to near band edge emission and a prominent peak corresponding to defect related visible emission are seen in the Photoluminescence (PL) spectra.
Synthesis and Characterization of Copper doped ZnO nanoparticles
Journal of chemical and pharmaceutical research, 2010
Nanocrystals of undoped and copper doped zinc oxide (Zn1-x Cu x O (where x = 0.00 to 0.05) were synthesized by coprecipitation method. Crystalline phases and optical absorption of prepared samples were determined by X-ray diffraction and UV-visible spectrophotometer. The average particles size was determined from X-ray line broadening. X-ray analyses reveals that Cu doped ZnO crystallizes in hexagonal wurtzite structure. The incorporation of Cu+2 in the place of Zn2+ provoked an increase in the size of nanocrystals as compared to undoped or pure ZnO. Optical absorption measurement indicates red shift in the absorption band edge upon Cu doping. The band gap decreases from 3.15 eV to 2.92 eV with copper (5 %) doping at temperature 450 oC.
Journal of Materials Science & Technology, 2014
Here, undoped and Cu doped ZnO nanoparticles (NPs) have been prepared by chemical co-precipitation technique. X-ray diffraction (XRD) results reveal that Cu ions are successfully doped into ZnO matrix without altering its wurtzite phase. The single wurtzite phase of ZnO is retained even for 10 wt% Cu doped ZnO sample. It is observed from the electron microscopy results that higher level of Cu doping varies the morphology of ZnO NPs from spherical to flat NPs. Moreover, the particle size is found to increase with the increase in Cu doping level. Raman spectroscopy results further confirm that Cu dopant has not altered the wurtzite structure of ZnO. Impedance spectroscopy results reveal that the dielectric constant and dielectric loss have increasing trend with Cu doping. Cu doping has been found to slightly decrease the bactericidal potency of ZnO nanoparticles.
Investigations on structural and optical properties of Cu doped ZnO
Pure and Cu-doped zinc oxide nanoparticles were prepared through a chemical route. The dopant concentration [Cu/Zn in atomic percentage (wt%)] is varied from 0 to 3 wt %. Structural characterization of the samples performed with XRD confirmed that all the nanoparticles are of zinc oxide having polycrystalline nature. Morphological studies were conducted using SEM to confirm the grain size and texture. The UV-Vis studies showed absorbance peaks in the 200 nm - 800 nm region. It is found that the absorbance does not significantly change. The above fact is further confirmed from the band gap calculations using the reflectance graphs. When analysed in terms of Burstein-Moss shift, an increase of bandgap from 3.42 to 3.54 eV with increasing Cu concentration is observed. In the PL studies a red-shift is observed with increasing dopant concentration.
Cu-doped ZnO nanoparticles synthesized by simple co-precipitation route
The European Physical Journal Plus, 2014
Cu-doped zinc oxide (CuxZn1-xO, x = 0-3%) nanoparticles were synthesized using the simple direct co-precipitation method with Zn(CH3COO)2 • H2O, Cu(CH3COO)2 and polyvinylenepyroliden (PVP) as raw materials. Structure, size distribution and morphology of the Cu-doped ZnO nanoparticles were studied by X-ray diffraction, transmission electron microscope (TEM) and scanning electron microscope (SEM), respectively. The optical and photoluminescence photospectroscopy were utilized to analyze the crystal defects of the ZnO nanoparticles. Cu addition does not change the hexagonal wurtzite structure of ZnO nanoparticles. The mean particle size is around 10 nm. The 0.01% Cu concentration causes maximal photoluminescence. The bandgap of ZnO nanoparticles was obtained around 3.93 eV due to quantum size effects.
Influence of Cu doping on the structural, electrical and optical properties of ZnO
Pure and Cu-doped zinc oxide (ZnO) nanoparticles were prepared using a chemical method. The dopant concentration (Cu/Zn in atomic percentage (wt%)) is varied from 0 to 3 wt%. Structural characterization of the samples performed using X-ray diffraction (XRD) confirmed that all the nanoparticles of zinc oxide are having polycrystalline nature. Morphological studies were conducted using field emission scanning electron microscopy (FESEM) to confirm the grain size and texture. Electrical measurements showed that the AC conductivity initially decreases and then rises with increasing Cu concentration. The UV–Vis studies showed absorbance peaks in the 200– 800 nm region. It is found that the absorbance does not significantly change with doping. This fact is further confirmed from the band-gap calculations using the reflectance graphs. When analysed in terms of Burstein–Moss shift, an increase of band gap from 3.42 to 3.54 eV with increasing Cu concentration is observed. In the photoluminescence (PL) studies a red-shift is observed with increasing dopant concentration.
Fabricated of Cu Doped ZnO Nanoparticles for Solar Cell Application
Baghdad Science Journal, 2018
Copper with different concentrations doped with zinc oxide nanoparticles were prepared from a mixture of zinc acetate and copper acetate with sodium hydroxide in aqueous solution. The structure of the prepared samples was done by X-ray diffraction, atomic force microscopy (AFM) and UV-VIS absorption spectrophotometer. Debye-Scherer formula was used to calculate the size of the prepared samples. The band gap of the nanoparticle ZnO was determined by using UV-VIS optical spectroscopy.
Journal of Materials Science and Chemical Engineering, 2015
Nanoparticles of Zn1−xCuxO system with nominal compositions x = 0.0, 0.01, 0.02 and 0.03 were prepared by co-precipitation method at room temperature. Structural, morphological, optical and chemical species of grown crystals were investigated by X-ray diffraction (XRD) technique, Scanning Electron Microscopy (SEM), UV-visible and FTIR spectroscopy, respectively. XRD analysis confirms that all samples have hexagonal structure with no impurity phases which suggest that Cu ion successfully incorporated into the regular ZnO crystal structure. The lattice parameters, volume of unit cell, X-ray density, atomic packing fraction, c/a ratio, and grain size were calculated from XRD pattern of pure and Cu doped ZnO samples and it was found that the grain size was in the range of 23 nm to 29 nm. The strain in pure and Cu doped ZnO samples was calculated by W-H analysis. Optical properties of Zn1−xCuxO samples were studied by using UV-vis spectrophotometer. Optical absorption spectra show that the band gap decreases with increasing Cu contents. The functional group and chemical interactions of Zn1−xCuxO samples were also determined at various peaks using FTIR data and observed that the functional groups corresponding to the Zn-O bands in the samples. The photocatalytic activities of the samples were investigated by oxidation of methylene blue under UV light illumination in batch reactor. The scavenger study was carried out to find out main reactive species responsible for the degradation of dyes.
International Journal of Nano and Biomaterials, 2017
Cu doped ZnO nanoparticles abbreviated as Zn 1-x Cu x O (x = 0, 0.01 and 0.03) were synthesised by high energy ball milling (HEBM) technique. The structural, morphological, optical and dielectric properties of the synthesised nanoparticles were carried out by XRD, FTIR, UV-Vis and impedance analyser, respectively. The incorporation of the dopant Cu into ZnO hexagonal wurtzite structure has been verified by X-ray diffraction (XRD). The effect of Cu doping on the structural bonding of ZnO has been verified by Fourier transformation infrared (FTIR) spectra. The XRD spectra shows that all the synthesised nanoparticles are single phase, hexagonal wurtzite structure and belong to the space group of p6 3 mc. Compared to pure ZnO (18 nm), the crystallite size of Cu doped ZnO (15 nm) is smaller and peak broadening exists in the system. A similar feature of FTIR spectra has been observed for all samples, which supports the hexagonal wurtzite structure of ZnO even after Cu doping. The band gap (E g) of ZnO decreases with Cu doping which can be attributed to sp-d exchange interaction between the ZnO band electrons and localised d electrons of Cu 2+ ions. The dielectric constant of ZnO decreases with Cu doping.
X-ray Absorption Studies on Cu–doped ZnO Nanoparticles Synthesized by Coprecipitation Method
IOP Conference Series: Materials Science and Engineering, 2018
Copper-doped ZnO (CZO) nanoparticles have successfully been synthesized by coprecipitation method with Cu concentrations ranging from 0 to 5 wt%. The effect of Cu concentration on electrical properties and the oxidation state of ZnO were investigated. The xray diffraction (XRD) pattern analysis shows CZO phase formed with calcination at 400 o C for 3 h. The crystal size of CZO nanoparticles, evaluated using MAUD software, is in the range of 56-90 nm. It was obtained that the Cu doping has reduced the optical band gap from 2.85 eV to 3.06 eV, while the electrical conductivity increased from 1.03 x 10-8 to 24.25 x 10-8 S/cm. The highest conductivity of CZO is achieved by the sample doped with 4 wt% Cu. This result has been further studied by the x-ray absorption near edge spectroscopy (XANES) measurement at Cu K-edge related to the oxidation state of the Cu ions substituting Zn sites.