Papers by Keyword: Cu₂O

Abstract: This work reported the successful fabrication of a low-cost electrospun PAN nanofiber coated with Cu₂O QDs. Our works reveal that the spray coating method was effective in applying a homogenous distribution of Cu₂O QDs on the surface of PAN nanofiber. The as-synthesized Cu₂O QDs have an absorption edge at 510 nm and band gap energy of 2.5 eV indicating a light-sensitive photocatalyst. The SEM image showed an even distribution of Cu₂O QDs on the top of PAN nanofibers with an average diameter of 454.45 ± 124.732 nm. The wettability of the as-made nanofibers was determined using the contact angle method. Our PAN/Cu₂O QDs nanofibers showed hydrophilic behavior. The reactive oxygen species generation study also indicated the ability of our PAN/Cu₂O to generate singlet oxygen. Our results indicate the promising potential of PAN/Cu₂O as wound healing fabric due to the advantageous natural properties of copper and hydrophilic fabric.

Abstract: Cuprous Oxide (Cu₂O) is a semiconductor material with excellent photocatalytic properties, a broad range of applications, low fabrication costs, and is non-toxic. We concentrated on the impact of two different synthesis methods in this study. Cu₂O synthesis was carried out using two different techniques, which are chemical deposition and hot-soap method. The chemical deposition (CD) method used a copper sulfate pentahydrate precursor in a room temperature reaction. Hot-soap (HS) method employed copper acetylacetonate with reaction at higher temperature. The X-Ray Diffraction analysis reveals a sharp peak with a size of 53.8 nm and a broaden peak with a size of 26.24 nm for particles synthesized by (Cu₂O-CD) and (Cu₂O-HS), respectively. Using the Tauc Plot method, the band gap of Cu₂O-HS is estimated to be 2.65 eV and that of Cu₂O-CD to be 1.7 eV. Cu2O-HS emits a noticeable photoluminescence peak at 425 nm, whereas Cu₂O-CD emits no peaks in photoluminescence spectra analysis. These findings indicate that Cu₂O-HS has a high potential for use in photocatalytic mechanisms.

Abstract: Nd:YAG laser was used at different number of shots (300, 500, and 700 pulse) to prepare ZnO:Cu₂O nanoparticles at mixing ratios of (0.5, 0.7 and 0.9). The optical, structural, morphological and electrical properties of the prepared films were investigated. The energy band gap was found to be (2.5, 3.2 and 3.53 e.v). The crystalline structure showed no impurity peaks indicating that the final product was free from surface impurities. Also, the materials peaks and intensity is present and well identified as the mixing ratio varies. The AFM results for all ratios indicate that as the number of pulses increase, the higher the resulted grain size. The average grain size was between (58.82 nm) to (95.75nm). The J-V characteristics were measured for the prepared solar cells and it was found that the efficiency varied with the mixing ratio and film thickness from 0.29% to 2.38%. F.F varied from 0.28 to 0.25.

Abstract: The changes in structural and optical properties of the Cu₂O films obtained on the glass with different concentrations of Au by the chemical bath method were studied in this work. Lattice parameter, crystal size, preferential orientation and surface tension of the films were calculated using X-ray diffraction data which showed that all of the films were in polycrystalline form. It was determined that the structural parameters of all films were changed with the doping ratio. The surface morphology of the films was imaged using a field emission scanning electron microscope. The optical properties of the films were discovered using the optic spectrometer. Changes in the optical properties were discovered as a function of Au ratio. It was determined that the energy band gap value (2.12 eV-2.02 eV), the refractive index, the extinction coefficient, the real and dielectric coefficients, the optical conductivity, and the skin depth of films varied with Au doping ratio.

Abstract: Colloidal solutions of copper (I) oxide, Cu₂O, were obtained by pulsed laser ablation of metallic copper target in distilled water using fundamental harmonic of Nd:YAG laser (1064 nm, 7 ns, 20 Hz). Nanocolloids obtained were applied to cotton fabric. Nanoparticles composition and structure were studied by UV-Vis and Raman spectroscopy, transmission and scanning electron microscopy, and XRD. Antibacterial activity of Cu₂O nanoparticles on cotton fabric to E.coli bacteria was demonstrated in comparison with zinc oxide nanoparticles.

Abstract: In this manuscript, we will describe the preparation of copper oxide thin films by sol-gel route using solar furnace with area of about 1.5 m² as a rapid thermal annealing apparatus. The gel films prepared by spin-coating of Cu acetate solution transferred to CuO or Cu₂O films after thermal annealing for 1 min employing solar furnace consists of Fresnel lens. The result reveals that the solar furnace can provide enough energy to cause the high temperature reaction of sol-gel route copper oxide synthesis. In addition, the result displays that the solar furnace is preferable apparatus to carry out a kind of high temperature rapid annealing. The oxidization reaction of the gel films significantly depends on the structure of the gel films before annealing. In the case of the gel film which contains little CuO, the film becomes mixture of CuO and Cu₂O after the annealing by solar furnace. In contrast, the gel film with CuO structure transferred to pure Cu₂O film after the annealing.

Abstract: Cu₂O, a p-type semiconductor, has broad potential applications, especially as a visible-light photocatalyst. This paper presents a simple water-bath reflux to prepare Cu₂O micro/nanoparticles. The morphology evolution from intact octahedrons to surface-pitted spheres was obtained by adjusting reducing agent and additive. Reflectance spectra show similar photo-absorption intensity and the same range from 250 nm to 650 nm. However, they perform different photocatalytic activity. Intact octahedron has the best photodegradation ability and next is vertex-and edge-damaged octahedron, the lowest for vertex-free polyhedrons and surface-pitted spheres. The enhanced photocatalytic activity for intact octahedrons should to be attributed to its surface characteristics of high index. Our study not only provides a simple method for controllable preparation of Cu₂O micro/nanoparticles with different morphologies but also confirms the effect of morphologies on photocatalytic activity.

Abstract: Using chitosan as raw material,the modified chitosan was obtained through alkylation reaction with alkyl halide, which as a carrier, Cu2O/ modified chitosan composite photocatalyst was prepared by hydrazine hydrate reduction.Using the method of X-ray diffraction and scanning electron microscope analysis, characterization of the composite photocatalyst show: Cu2O loads evenly on the modified chitosan, and the structure of Cu2O changes little, grain size of Cu2O is about 200nm~300nm.Using UV mercury lamp as the light source, alizarin red as target degradation product, photocatalytic performance of the Cu2O/modified chitosan photocatalyst was researched.The results show that: As the loaded modified chitosan produces a synergistic effect with Cu2O, its degradation rate of the dye improves in the UV mercury lamp,when the concentration of alizarin red is 50mg/L of the experimental conditions, the composite catalyst dyedegradation better than separate Cu2O catalysts and modified chitosan; absorption mainly dominates in composite photocatalyst under no light.

Abstract: Most of the photovoltaic industry uses wafer of single-crystal and poly-crystal silicon as a material of their photovoltaic (PV) modules. However, the cost of these modules is high due to the material and processing cost. Cuprous oxides (Cu2O) have several features that suitable for future photovoltaic applications. Cu2O can be prepared with simple methods at very low cost. Cu2O p-n homojunction solar cell is a device that converts sunlight to electrical energy, consists of two similar materials for its p-n junction, which is Cu2O. The p-type and n-type of Cu2O thin films are then fabricated to produce solar cells. Other layers aluminium and glass substrate coated with indium tin oxide (ITO) need to be added as a contact for electrons movement. In this study, p-type Cu2O, n-type Cu2O and p-n junction are prepared in order to become accustomed for solar cell applications. To achieve the optimum deposition conditions, p-n junction solar cell is prepared by two-steps electrochemical deposition process. The result from x-ray diffraction (XRD) shows that the peak is dominated by CuO (1, 1, 1). P-n junction is in between the p-type and n-type of Cu2O layer. Al has the thickness of 427.5nm. The second and the third layer are p and n type of Cu2O, which have the thickness of 106.9nm and 92.3nm, respectively. Finally the thickness of ITO layer is 131.1nm.An absorption experiment at AM1 light is performed in order to get the I-V curves, and in fact, to study the electrical solar cells p-n homojunction. Based on I-V curve test, the level of energy conversion of cell is 0.00141% with fill factor, FF 0.94813 which proved that Cu2O p-n homojunction solar cell can be fabricated and produced at very low cost and well function.

Abstract: Four kinds of Cu₂O microcrystals with different morphologies are synthesized via low temperature hydrothermal synthetic method. The photocatalytic degradation of methylene blue (MB) of the above different Cu₂O is preliminary explored based on this observation. 6-facet, 8-facet, 14-facet are prepared by PVP system and 26-facet is prepared by NaOH system. They are characterized by means of Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Diffuse Reflectance Spectra (DRS). Under 150 W xenon lamp irradiation, 0.5 gL¹ catalyst and 0.1% (v/v) 30% H₂O₂ as co-catalyst are used to degrade 5% 100 mL MB solution. The reaction time is 80 min. 26-facet Cu₂O polyhedral discolor about 89.48% of MB while 6-facet Cu₂O microcrystal about discolor about 20.18% which is the lowest decolourization rate among all the samples. The photocatalytic performance of 8-facet Cu₂O microcrystal is slight better than that of 14-facet. The decolourization rate of 8-facet and 14-facet are 56.00% and 41.08%, respectively. The main reason is that the planes of Cu₂O microcrystal have a main influence on photocatalytic degradation of MB.