Copper Doped Zinc Oxide Nanoparticles Research Articles

Dependence of the electrical properties of Cu-doped ZnO nanoparticles decorated by Ag atoms

Abstract Silver decorated copper doped zinc oxide nanoparticles (Ag@Cu-ZnO) were successfully prepared via sol gel method. X-ray diffraction analysis revealed ZnO wurtzite crystalline structure with the existence of minor peaks attributed to Cu and Ag. The presence of Cu and Ag in addition to ZnO lattice was supplementary verified by EDS data while the shift in the FTIR band confirmed the Cu incorporation within the ZnO host lattice. Both SEM and XRD revealed an increase in particle size with Ag loading. At different frequencies, electrical measurements demonstrated a decrement in the dielectric constant, dielectric loss and AC conductivity with the increment of Ag content. Meanwhile, the Nyquist plots of the impedance measurement showed a single semicircle arc indicating the predominance of grain boundary resistance. This study elucidated the great influence of Ag on Cu-doped ZnO nanoparticles’ structural, dielectric constant and electrical conductivity which make it a promising candidate for catalytic, photocatalytic and adsorption applications.

Copper-Zinc Oxide Synergistic Approach as Low-Emissivity Material for Energy-Saving Windows

In luxurious glass buildings and constructions, heat gain (or heat loss) mostly comes through the windows. Infrared (IR) radiation is an important factor that causes the entry of heat into the buildings. To save energy consumption of air conditioners, low-emissivity (Low-E) glass coating applications are focused. In the energy-saving field, transparent conductive oxide (TCOs) are used as coatings to minimized IR entry. In this work, copper-doped zinc oxide (CZO) is synthesized for thermal reflective material. Cu(II) ions are doped to ZnO by a sol-gel method to obtain CZO nanoparticles and is coated on a glass substrate. The morphology of CZO is investigated with scanning electron microscopy (SEM); phase crystallinity is determined by X-ray diffraction (XRD); and UV-Vis-NIR spectroscopy is used to characterize UV/IR-shielding and also the optical transparency. IR cameras and in-lab thermal insulation setup are used to test the heat insulation properties. The result shows that 15% copper-doped zinc oxide has the best insulation from IR rays with the lowest temperature in the interior (T3) of 50.6°C while the outer temperature (T2) was at 85.5°C the lowering of the temperature by 34.9°C (cooler by 59%). CZO synthesized from the sol-gel method has promising properties for Low-E glass coating applications.

Synthesis, Characterization and Evaluation of Antimicrobial, Antioxidant & Anticancer Activities of Copper Doped Zinc Oxide Nanoparticles

The present work reveals the influence of copper (Cu) doping in band gap energy level as well as selective cytotoxicity of ZnO nanoparticles against human breast cancer cells (MCF7), human cervical carcinoma (HeLa), and one normal (Vero) cell line. Cu-doped ZnO nanoparticles (Cu-ZnO NPs) were synthesized and validated by UV-Vis, FT-IR, XRD, SEM and EDX. Cu-doping diminished the band gap energy of ZnO NPs from 3.54 eV to 3.29 eV. Antimicrobial activity has been evaluated against three bacterial and fungal strains. Antioxidant activity was examined using a DPPH free radical, ABTS+ radicals, hydroxyl radicals and nitric oxide scavenging assay. Cu-ZnO NPs showed anticancer activity with IC50 value of 219.56 µg/mL against MCF7 and 137.27 µg/mL against HeLa cell lines. The doping of Cu with ZnO improved the selective cytotoxicity of ZnO NPs towards MCF7 and HeLa cells without affecting the normal cells.

Copper-Doped Zinc Oxide Nanoparticles for the Fabrication of white LEDs

Zinc oxide (ZnO) is the most commonly and widely studied material in the field of nano science and technology due to its unique characteristics, such as wide band gap energy (3.37 eV), electrical and thermal stability, large exciton binding energy (60 meV), biocompatibility and biosafety. Copper is considered as an important dopant for ZnO due to their almost similar ionic radii which enhances the properties of ZnO. Thus, pure and copper-doped nanocrystalline ZnO particles were synthesized through sol–gel approach in the current study. The concentration of the dopant is varied from (0.1–0.3%) and the composition, structural and optical characterizations were performed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, UV-Vis optical absorption and photoluminescence (PL) spectrometer. The structural analysis confirmed that copper ions substitute Zn ions without altering their wurtzite structure and a crystallite size of 10–16 nm with high degree of crystallization. Morphological properties conducted using SEM confirmed copper doping strongly influenced the grain size and morphology of ZnO NPs. Moreover, the morphology variation is observed from spherical nanoparticles to nanorods with Cu (0.2%) doping into host matrix. The morphological variation may be attributed to strong influence of Cu ions on the growth rate of ZnO. PL measurement had been carried out at room temperature in which high intensity broad emission peaks were observed in visible region around 450–700 nm that indicates the superposition of green and yellow-orange emission bands. Currently, light-emitting diodes (LEDs) giving green light emission have been combined with broad-band visible phosphors to make white-light LEDs. Thus, green photo luminescent copper-doped ZnO nanoparticles from the current study is highly significant in the fabrication of white-light LEDs.

Retraction: Assessment of photocatalytic potentiality and determination of ecotoxicity (using plant model for better environmental applicability) of synthesized copper, copper oxide and copper-doped zinc oxide nanoparticles.

Retraction: Assessment of photocatalytic potentiality and determination of ecotoxicity (using plant model for better environmental applicability) of synthesized copper, copper oxide and copper-doped zinc oxide nanoparticles.

Development of an impedimetric non enzymatic sensor based on ZnO and Cu doped ZnO nanoparticles for the detection of glucose

In this research, pure and copper-doped Zinc oxide nanoparticles (Cu-ZO) have been prepared by sol gel method. Lots of tests have been carried out for the prepared samples such as crystallinity analysis, microstructures observation and electrochemical property investigations. The electrochemical behavior of the electrodes were evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). These analyses show that the ZnO and Cu-ZO samples are promising for the development of cost effective non-enzymatic electrochemical glucose biosensors with good features. The prepared Cu-ZO samples sensor represent higher sensitivity and superior electro catalytic activity as compared to that observed for the undoped ZnO nanoparticles. It exhibit a large linear detection range from 10−9 M to 10−5 M and low detection limit of 10−9 M. It is believed that the copper doping revealed a significant effect on the electrochemical properties because it provide more electro catalytic actives sites and more electron transfer for glucose oxidation. Furthermore, measurements in the presence of interfering species haven't affected the response of the analyte of interest which prove the good selectivity of the Cu-ZO. Finally, the electrode was successfully applied to the assess the glucose level in human serum samples.

Structural and optical properties of pure and copper doped zinc oxide nanoparticles

Abstract Pure and copper-doped zinc oxide nanoparticles (NPs) have been synthesized via chemical co-precipitation method where hydrazine is used as reducing agent and aqueous extract of Euphorbia milii plant as capping agent. Main objectives of the reported work are to investigate the effect of copper doping on crystal structure of ZnO nanoparticles; to study the effect of copper doping on optical band gap of ZnO nanoparticles and photoluminescence (PL) study of pure and copper-doped ZnO nanoparticles. To achieve the aforementioned objectives, XRD and SEM tests were performed for the identification and confirmation of crystal structure and morphology of the prepared samples. From XRD data the average grain size for pure ZnO was observed to be 24.62 nm which was first decreased to 18.95 nm for 5 wt% Cu-doped sample and then it was found to increase up to 37.80 nm as the Cu doping was increased to 7 wt%. Optical band gap of pure and Cu-doped ZnO nanoparticles was calculated from diffuse reflectance spectroscopy (DRS) spectra and was found to decrease from 3.13 eV to 2.94 eV as the amount of Cu increases up to 7 wt%. In photoluminescence study, PL technique was used and enhanced visible spectrum was observed. For further characterization FT-IR and EDX tests were also carried out.

Study of nanosized copper-doped ZnO dilute magnetic semiconductor thick films for spintronic device applications

Screen-printed pure and copper-doped ZnO dilute magnetic semiconductor thick films were casted from chemically co-precipitated zinc oxide and copper-doped zinc oxide nanoparticles followed by sintering at 550 °C to obtain desired stoichiometry in spintronic device applications. These thick films were characterized by different analytical techniques to reveal their structure, surface morphology, optical, magnetic and electrical characteristics. The diffraction peaks pertaining to wurtzite structure are observed in XRD patterns of these films, while SEM images show smooth and dense morphology. Infrared transmission and Raman spectra exhibit vibrational bands pertaining to Zn–O-stretching modes and E 2 (high) phonon mode, respectively, in 4000–400 cm−1 region. The direct bandgap energy of these films derived from diffused reflectance spectroscopy varies in 3.21–3.13 eV range and is supported by PL spectroscopy study. The semiconducting behaviour and activation energy of these thick films has been confirmed by DC conductivity measurements. Electron paramagnetic resonance spectra showed derivative signal of g value 2.0018 in pure ZnO due to oxygen vacancies produced during synthesis and 2.0704 in copper-doped ZnO dilute magnetic semiconductor films.

Assessment of photocatalytic potentiality and determination of ecotoxicity (using plant model for better environmental applicability) of synthesized copper, copper oxide and copper-doped zinc oxide nanoparticles.

NPs synthesis, characterization and azo-dye degradationA facile cost effective wet chemical method of synthesis is proposed for Cu-NPs, CuO-NPs and Cu-doped ZnO-NPs. The nanomaterials are opto-physically characterized for nano standard quality. Cu-doped ZnO-NPs based catalytic system is found to possess most efficient photocatalytic activity in degradation of two organic azo-dyes namely methyl red (MR) and malachite green (MG) that are released as industrial effluents in eco-environment intercollegium. Two possible photocatalytic degradation pathways are proposed to understand the mechanism of interaction prevailing during the mineralization of MR and MG dyes. Such study provides insight for waste water management. The uniqueness of the present work is 1) possible routes of MG dye degradation by Cu-doped ZnO-NPs and subsequent intermediate by-products are novel and pioneered of its kind. 2) two new intermediate byproducts are identified suggesting prevalence of multiple MR degradation pathways by Cu-doped ZnO-NPs.Assessment of ecotoxicityFor assessment of residual NPs impact on environment, eco-toxicological assay is performed using plant system (Sesamum indicum L.) as model. The study encompasses seed germination, seedling morphology, quantification of endogenous H2O2 and MDA generation, estimation of DNA double strand break and analysis of cell cycle inhibition. Results highlight reduced ecotoxicity of Cu-doped ZnO-NPs compared to the other synthesized nanomaterials thereby suggesting better environmental applicability in waste water purification.

Synthesis and characterization of copper zinc oxide nanoparticles obtained via metathesis process**Contribution at the 4th Southeast Asia Conference on Thermoelectrics 2016 (SACT 2016), 15–18 December 2016, Da Nang City, Vietnam.

Copper-doped zinc oxide nanoparticles were successfully synthesized by grinding copper acetate and zinc acetate powder with different starting molar ratios in combined with sodium hydroxide. The effect of initial copper and zinc molar ratios on the product samples was investigated and discussed. Relevant ligand coordination type of reactant acetate salt precursors and product samples were investigated by Fourier transform infrared spectroscopy (FTIR). The particle shapes and surface morphologies were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Phase structures of prepared samples were studied by x-ray powder diffraction (XRD) and x-ray absorption near-edge spectroscopy (XANES) was applied to investigate the local structure of Cu and Zn environment atoms. The results demonstrate that the, particle size of as-synthesized products affected by copper concentration in the precursor trend to gradually decreases from nanorod shape with diameter around 50–100 nm to irregular particle structure around 5 nm associated with an increase in the concentration of copper in precursor. Moreover, it is noticed that shape and morphology of the products are strongly dependent on Cu:Zn ratios during the synthesis. Nanocrystallines Cu-doped ZnO by the substitution in Zn site with a high crystallization degree of hexagonal wurtzite structure were obtained. This synthesis technique is suggested as a potential effective technique for preparing copper zinc oxide nanoparticles with various atomic ratio in wide range of applications.

Comparative study of post-sintering temperature on properties of copper doped zinc oxide nanoparticles prepared by co-precipitation process

Copper doped zinc oxide nanoparticles (Cu doped ZnO NPs) has been prepared by co-precipitation process using zinc nitrate, copper nitrate and potassium hydroxide as zinc, copper and hydroxide precursor, respectively. All of prepared conditions were fixed as the concentration of copper in zinc oxide about atomic percentage at 2%. The prepared powders of Cu doped ZnO NPs were studied with various post-sintering temperature at 500, 600 and 700 °C. All of samples were characterized using X-ray Diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FT-IR). The EDX spectra showed the qualitative and quantitative elemental composition of prepared material, meanwhile, XRD peaks represented Cu doped ZnO NPs in hexagonal wurtzite structure. The improvement in crystallinity of Cu doped ZnO NPs could be performed by sintering process. Moreover, the SEM and TEM images showed that the Cu doped ZnO NPs were condensed to the larger particles size by the increase of sintering temperature. Finally, the FT-IR spectra showed a broad absorption band for all of samples.

Thermal, structural and optical investigation of Cu-doped ZnO nanoparticles

Well-dispersed undoped and copper-doped zinc oxide nanoparticles (Zn[Formula: see text]Cu[Formula: see text]O, [Formula: see text] = 0, 1, 5 and 10 wt.%) have been synthesized by precipitation method at room temperature. X-ray diffraction data revealed that the undoped and copper-doped zinc oxide nanoparticles are in phase pure wurtzite structure and the crystallite size increases from 24 nm to 36 nm with increase in dopant concentration. The optical band gap was found to decrease with increasing dopant concentration, which clearly indicates the blue shift. High-resolution scanning electron microscope image shows that the synthesized samples consist of an assembly of nanopetals. Transmission electron microscope image also confirmed the average particle size of 20–50 nm. Energy-dispersive X-ray spectrum shows that the prepared samples are free from impurities. Photoluminescence spectra exposed that copper ions are doped into the lattice positions of ZnO. A simultaneous differential scanning calorimeter/thermogravimetric analysis combination was used to study the phase variations.

Synthesis and characterization of copper doped zinc oxide nanoparticles and its application in energy conversion

Solar cells, in general, perform under light source of solar influx, while the heat energy of solar radiation remains unutilized. Using an aqueous suspension of copper doped zinc oxide nanoparticles in specially-designed electrochemical cells we have observed significant voltage (maximum 632.0 mV) and storage duration (∼47 h) upon thermal excitation. The cells exhibit reasonable energy conversion efficiency (maximum 1.36%). These cells generate voltage even at room temperature (∼30 °C) and the voltage increases gradually with increasing temperature. When the platinum foil separating the two compartments of the electrochemical cell is replaced by a planar lipid membrane, all the parameters e.g., thermovoltage, storage capacity and the energy conversion efficiency increase significantly.

Electrical and gas sensing properties of self-aligned copper-doped zinc oxide nanoparticles

Electrical and gas sensing properties of nanocrystalline ZnO:Cu, having Cu Xwt% (X=0.0, 0.5, 1.0, and 1.5) in ZnO, in the form of pellet were investigated. Copper chloride and zinc acetate were used as precursors along with oxalic acid as a precipitating reagent in methanol. Material characterization was done by X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM) and inductive coupled plasma with optical emission spectrometry (ICP-OES). FE-SEM showed the self-aligned Cu-doped ZnO nano-clusters with particles in the range of 40–45nm. The doping of 0.5% of copper changes the electrical conductivity by an order of magnitude whereas the temperature coefficient of resistance (TCR) reduces with increase in copper wt% in ZnO. The material has shown an excellent sensitivity for the H2, LPG and CO gases with limited temperature selectivity through the optimized operating temperature of 130, 190 and 220°C for H2, LPG and CO gases, respectively at 625ppm gas concentration. The %SF was observed to be 1460 for H2 at 1% Cu doping whereas the 0.5% Cu doping offered %SF of 950 and 520 for CO and LPG, respectively. The response and recovery time was found to be 6 to 8s and 16s, respectively.