Optical Properties Of Cu Research Articles

Impact of oxygen vacancies on the structural, electronic, and optical properties of Cu<i>2</i>O and nitrogen-doped Cu<sub>2</sub>O for optoelectronic applications: a first-principles study

This study utilizes Density Functional Theory (DFT) within the Quantum ESPRESSO framework to explore the effects of oxygen vacancies and nitrogen doping on the electronic structure and optical properties of cuprous oxide (Cu2O). Pristine Cu2O, an intrinsic p-type semiconductor, typically exhibits a direct band gap. Introducing an oxygen vacancy in the absence of a dopant broadens the band structure, leading to both direct and indirect band gap characteristics. In contrast, nitrogen doping transforms the band gap into a direct one, significantly reducing it from 1.97 eV to 1.09 eV, which deviates from previous findings due to potential variations in the initial state of the Cu2O host crystal. Furthermore, spin-polarization effects indicate spin-dependent behaviour within the material. The study also examines the absorption properties of pristine, defective, and nitrogen-doped Cu2O systems using the complex dielectric function. The results show distinct absorption peaks and transitions, with nitrogen-doped Cu2O exhibiting strong absorption in the visible light range, underscoring its potential for solar cell applications.

Tailoring structural and optical properties of Cu(II)-induced MgAl2O4 nanoparticles and their response to toxic dyes under solar illumination.

Worldwide environmental challenges pose critical problems with the growth of the global economy. Addressing these issues requires the development of an eco-friendly and sustainable catalyst for degrading organic dye pollutants. In this study, copper-doped magnesium aluminates (CuxMg1-xAl2O4) with x = 0.0-0.8 were synthesized using a citrate-based combustion route. The inclusion of Cu(II) significantly impacted the structural, microstructural, optical, and photocatalytic activity of the catalyst. Rietveld analysis of X-ray diffraction powder profiles revealed single-phase spinels crystallized in the face-centered cubic unit cell with space group. Chemical states of the ions, surface morphology, and elemental investigation were analyzed by X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy, respectively. UV-visible and diffuse reflectance spectroscopies confirmed the reduction of the band gap due to Cu(II) doping, validated by first-principle investigations using the WIEN2k code. The catalyst with x = 0.8 showed higher photocatalytic efficacy (90% and 93%) for removing two azo organic dye pollutants, rhodamine B and methyl orange, respectively, within 120min. Degradation kinetics followed a pseudo-first-order mechanism. The doped (0.8) sample was structurally and morphologically stable and reusable under visible irradiation, retaining performance after three runs. Scavenger studies confirmed hydroxyl and superoxide radicals' involvement in the degradation. This work presents an effective approach to enhancing CuxMg1-xAl2O4 catalysts' photodegradation performance, with potential applications in pharmaceuticals and wastewater remediation.

Structural and optical properties of Cu:CdS thin films on soft polymer substrate

Structural and optical properties of Cu:CdS thin films on soft polymer substrate

Elucidation of structural, electromagnetic, and optical properties of Cu–Mg ferrite nanoparticles

Copper doped magnesium ferrite, Mg1-xCuxFe2O4(x = 0.0–1.0) nanomaterials were synthesized via. sol-gel method sintered at 600 °C for 2 h. The synthesized materials were characterized using modern sophisticated techniques viz. X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy, Energy dispersive x-ray spectroscopy (EDS), Vibrating sample magnetometer, UV–visible diffuse reflectance spectra and Impedance analyzer. XRD analysis revealed that all the samples were single phase cubic spinel structure with Fd3m space group and investigated the change in structural parameters with copper concentration. The average crystallite size in the range of 11–23 nm and lattice parameters decrease with increasing Cu doping, due to the cationic distribution and ionic radius. The SEM images show the agglomeration of the particles with spherical like shape and elemental percentage were obtained from EDX. The saturation magnetization showed an increasing trend with increasing Cu concentration at a certain level and then decreases due to the rearrangement of cations at tetrahedral and octahedral sites. The Coercivity, Retentivity and magnetic crystalline anisotropy increase with changing dopant concentration. The magnetic measurements showed enhanced saturation magnetization at certain level (28.96emu/gm) and increase in coercivity up to 1102 Oe with changing dopant concentration. The estimated band gap energy is found to increase with Cu content. The dielectric constant, dielectric loss and impedance show normal behavior of ferrite. The frequency dependent dielectric constant decrease and tan delta shows a relaxation behavior at low frequencies. The synthesized nano Mg–Cu nanoparticles will be applied as humidity sensor, gas sensor, microwave devices and photocatalyst.

Bicone nanoflower evolution and multi-peak emission of polymer caped Cu doped ZnO.

A low-temperature polymer-assisted wet chemical method was used to synthesise Cu-doped ZnO bicone nanoflowers at three different PEG concentrations.The effects of PEG concentration on the structural, morphological and optical properties of Cu doped ZnO nanostructures were studied. X-ray diffraction studies revealed that the as-synthesized ZnO nanostructures are highly crystalline with a hexagonal wurtzite phase. The scanning electron microscopy (SEM) analysis showed that the prepared nanostructures have bicone-nanoflower morphology and PEG concentration has strongly influenced the size as well the shape of nanoflowers. The surface passivation effect of PEG on the band gap energies was studied by analysing UV -visible spectra of all the samples. The room-temperature fluorescent spectra of all the nanoflowers showed multiple peak emissions, both in the ultra-violet and visible regions, with varying intensities.These recasted multiple peaks are attributed to the morphological modification caused by the PEG addition.&#xD.

Comprehensive structural analysis, magnetic, elastic, and optical properties of Cu–Ni–Co spinel and its potential applications

This work investigates the Cu0·6Ni0·2Co0·2FeAlO4 (CNCFAO) spinel nanoparticle, focusing on its structural, magnetic, elastic, and optical properties. The structural analysis provided various parameters, such as lattice parameter, crystallite size, and bond lengths, which were compared to theoretical values. The force constants of the sample were used to calculate stiffness constants (C11, C12, and C44), which in turn were used to determine elastic moduli such as the bulk modulus (B), longitudinal modulus (L), and rigidity modulus (G). The calculated Pugh ratio (B/G) indicated the brittle mechanical nature of the sample, while the Poisson ratio (σ) was estimated as σ = 0.25, consistent with isotropic elasticity theory. The sample demonstrated a low coercive field, indicating its potential for soft magnetic devices. Optical characteristics were evaluated using the Tauc method, revealing a direct optical transition with estimated band-gap (Eg) and Urbach (Eu) energies of 2.38 eV and 0.59 eV, respectively. Additional optical properties, including the penetration depth, refractive index, and extinction coefficient, were thoroughly examined. These results provide valuable insights into the potential optoelectronic applications of the synthesized sample.

Investigation of structural, electrical, magnetic, and optical properties of Cu (111) and the impact of Ag adatoms adsorption: A density functional theory study

Our study conducts a comprehensive investigation on the structural, electrical, magnetic and optical properties of pure Cu with a (111) crystallographic orientation, as well as the impact of the adsorption of Ag adatoms on a Cu (111) surface. To perform this analysis, we utilized the full potential linearized augmented plane-wave (FP-LAPW) approach in conjunction with Generalized Gradient Approximations (GGA + U) and the Wien2k simulation software. Specifically, we calculated electrical and optical properties including the band structure, density of states (DOS) for the Cu (111) surface with and without the presence of adsorbed Ag atoms. Based on the observed results, the overlapping of the electronic bands for simple Cu (111) is comparatively less than that of adsorbed Ag/Cu (111) slab, indicating higher conductivity. Moreover, the evolutions are also observed which are mainly due to d orbitals of Cu and Ag for Cu (111) and Cu/Ag (111) respectively. The calculated magnetic optimization and weak diamagnetic magnetic moments shows weak diamagnetism in these materials. The optical properties like Dielectric Function(ε), Refractive index(n), Extinction co-efficient(k), Reflectivity(R), Energy Loss (L), Absorption (α) and Optical conduction (σ) are calculated. Our research examines the importance of band structure calculation in relation to optical properties. We discuss how plasmon-energy plays a crucial role in producing peaks in the energy loss function, with a crystallographic axis of 13.7 eV and 13.6 eV for both Cu (111) and Ag/Cu (111) slab. In addition, we calculated the static dielectric function, absorption coefficient, and refraction values for these materials. Reflectivity spectra for both Cu (111) and Ag/Cu (111) exhibits Infra-red region, indicating good coating materials to reduce heating, for the application of electrical appliances and for optical application like anti-reflecting coating, optical fibers and solar cells.

Optical properties of Cu, Ag, and Au nanoparticles with different sizes and shapes

AbstractThe absorption spectra of various sizes of nanoparticles of copper (Cu), silver (Ag), and gold (Au) are theoretically investigated. The density functional theory (DFT), time‐dependent DFT (TDDFT), and real‐time TDDFT are used to demonstrate how size and shape affect their optical properties and how these are evolved as the number of atoms increases. For this reason, the focus was turned on almost spherical nanoparticles cut out from the corresponding crystal structure (called 0D), elongated ones (1D), and flattened ones (2D). The nature of the observed absorption peaks is further analyzed with the help of transition contribution maps and induced density plots which help us identify the emergence of probable plasmonic resonances as the size of the nanoparticles increases.

Effects of strain and thickness on the mechanical, electronic, and optical properties of Cu2Te.

Two-dimensional transition-metal chalcogenides (TMCs) have attracted considerable attention because of their exceptional photoelectric properties, finding applications in diverse fields such as photovoltaics, lithium-ion batteries, catalysis, and energy conversion and storage. Recently, experimentally fabricated monolayers of semiconducting Cu2Te have emerged as intriguing materials with outstanding thermal and photoelectric characteristics. In this study, we employ first-principles calculations to investigate the mechanical, electronic, and optical properties of monolayer Cu2Te exhibiting both λ and ζ structures, considering the effects of thickness and strain. The calculations reveal the robust mechanical stability of λ-Cu2Te and ζ-Cu2Te under varying thickness and strain conditions. By applying -5% to +5% strain, the band gaps can be modulated, with ζ-Cu2Te exhibiting an indirect-to-direct transition at a biaxial strain of +5%. In addition, a semiconductor-to-metal transition is observed for both ζ-Cu2Te and λ-Cu2Te with increasing thickness. The absorption spectra of λ-Cu2Te and ζ-Cu2Te exhibit a redshift with an increase in the number of layers. These computational insights into Cu2Te provide valuable information for potential applications in nano-electromechanical systems, optoelectronics, and photocatalytic devices and may guide subsequent experimental research efforts.

Structural and optical properties of Cu implanted Ge thin films

Effects of rapid thermal annealing (RTA) on 100 keV Cu implanted germanium (Ge) thin films were studied in the present report. The Cu ion implantation into Ge films was carried out at different ion fluences 5 × 1015 and 1 × 1016 ions/cm2. Subsequently, the implanted samples were subjected to RTA at 600 °C. XRD and Raman results illustrate the amorphization of implanted films, whereas RTA results in crystallization. Crystallite size increases from 10.5 to 11.6 nm with fluence for RTA-treated samples. The bandgap of pristine film is 0.73 eV, which gets narrowed to 0.59 eV with an increase in ion fluence. RTA leads to increase in band gap up to 1.16 eV due to recovery of lattice damage and recrystallization of films. XPS analysis of RTA-treated implanted films reveals the presence of Ge, Ge suboxides, and Cu. The broad PL emission in the visible region signifies the possible use of Ge for optoelectronic applications.

First-principles study of structural, electronic and optoelectronic properties of Ag-doped Cu2O alloys: TB-mBJ insights

The structural, electronic and optical properties of Cu[Formula: see text]Ag[Formula: see text]O alloys ([Formula: see text], 0.25, 0.50, 0.75 and 1) have been investigated under the framework of the density functional theory (DFT), where the exchange and correlation potential is defined by the generalized gradient approximation of TB-mBJ (TB-mBJ-GGA). The equilibrium lattice constant ([Formula: see text]), bulk modulus ([Formula: see text]) and its first-pressure derivative ([Formula: see text]) are determined for each Cu[Formula: see text]Ag[Formula: see text]O alloys ([Formula: see text], 0.25, 0.50, 0.75 and 1). Based on the equilibrium lattice parameters, the electronic structure of Ag-doped Cu2O alloys is investigated in order to identify the electronic behavior of each compound; this leads to the fact that all Cu2O, Cu[Formula: see text]Ag[Formula: see text]O, CuAgO, Cu[Formula: see text]Ag[Formula: see text]O and Ag2O compounds are semiconductors. Furthermore, the optical properties of these compounds are calculated such as the complex dielectric constant, the complex refractive index, the absorption coefficient and the optical reflectivity.

Influence of Annealing Temperature on the Optical Properties of Cu Doped Zinc Oxide Films

Influence of Annealing Temperature on the Optical Properties of Cu Doped Zinc Oxide Films

First principles study on electronic and optical properties of Cu[formula omitted]CoGeS[formula omitted] for photovoltaic conversion and photocatalytic applications

In this study, the structural, electrical, and optical characteristics of the Stannite Cu2CoGeS4 (CCGS) are investigated using first-principle calculations. Band gap energy is determined using both the mBJ + U and HSE potentials. Both methods yield to similar results (1.73 1.73 eV and 1.78 eV for the first and second, respectively and 1.78 eV for the first and second, respectively). Based on our numerical simulations, CCGS is a viable absorber material for solar systems due to its exceptionally high absorption coefficient (on the order of 104 cm−1). This work also determines other optical parameters such as the refraction index and the dielectric function. In addition, the SCAPS program was used to conduct a simulation of solar cells based on CCGS. Based on the computed values of the short-circuit current density Jsc, open-circuit voltage Voc, Fill factor FF, and power conversion efficiency, CCGS is presented as a good choice for solar cells. We also explored the potential of CCGS for photocatalytic water splitting.

Synthesis, structural and optical properties of Cu doped ZnO and CuO–ZnO composite nanoparticles

Hydrothermal synthesis was used to obtain pure, doped and composite semiconductor oxide materials. We synthesized ZnO, CuO, Cu doped ZnO with 1, 2 and 3 wt %, and for Cu additions at 6, 8, 10, 15, 30 and 50 wt% this resulted in ZnO–CuO composites with different morphologies. X-ray diffraction (XRD) showed hexagonal and monoclinic crystalline phases for pure ZnO and CuO, respectively. Electron microscope images showed two-dimensional (2D) shaped particles. The Cu element could dope ZnO up to 3 wt%, whilst above this value, composites of ZnO–CuO were generated, with two segregated phases having flake-like shaped elongated particles. The visible-light absorption increases for the doped samples, being directly proportional to the Cu content for the dopant and the composite particles, showing a broad absorption range between 200 and 800 nm. Two bandgap energy values of 3.22 and 1.45 eV were determined for the ZnO–CuO samples. The samples were studied by X-ray photoelectron spectroscopy (XPS) in order to understand the doping process and composite formation.

The influence of post-annealing temperatures on XPS, XZ height of nanoparticles, and optical properties of Cu–Al doped ZnO films

In this article, using a radio frequency magnetron sputtering system at room temperature, Cu–Al doped ZnO films were deposited on quartz substrates. XPS studies have shown that the broad bands at around 932.5, 943, and 952 eV correspond to the Cu 2 P3/2 peak of Cu+1, Cu 2p3/2 of Cu+2, and Cu 2p1/2, respectively. In the case of Al2p3/2, the peak with binding energy 74.2 eV may be attributed to the presence of Al3+ oxide. The optical density, D opt, of films annealed at 600 °C has a maximum value about of 0.25. Films annealed at 600 °C have a minimum value of the fractal dimensions, D f, about 2.65. It is observed that films annealed at 500 °C, have a maximum value of the single layer. The minimum value of dissipation factor occurred in films annealed at 500 °C. It can be seen that with doping Cu and Al atoms into ZnO films, the oxygen vacancies were nearly removed and the quality of films was increased; hence the porosity which is introduced in ZnO films can be removed by Cu–Al doping of ZnO films. Due to high evaporation in films annealed at 600 °C, they were rougher and they have a maximum value of RMS roughness at about 4.68 nm. Films annealed at 400 °C have a minimum value of dissipation factor.

Molecular dynamic simulations for interactions of oxytetracycline with copper(II)-exchanged NaY zeolite

• Surface structure reflections on interactions of OTC with Cu 2+ -Y was explored. • The Raman spectra revealed ion exchange took place at the 4-ring I site. • Cu 2+ -Y offered reducing strain broadening and narrow particle size distribution. • MD simulation revealed ability of Cu 2+ -Y to attract OTC at force interaction. This study was devoted to examine the effect of the surface structure of Cu 2+ -Y against pure NaY on the photodegradation of oxytetracycline (OTC). The lattice strain examined by Rietveld analysis of XRD data showed strain induced peak broadening at 0.124 for NaY, which diminished to 0.119 for Cu 2+ -Y, prompted by the exchange of Cu 2+ onto the NaY zeolite. Scanning electron microscope (SEM) statistical analysis of Cu 2+ -Y revealed better crystallinity with larger cube width, >2 µm, compared with NaY, 1.7 µm. The vibrational modes and optical properties of Cu 2+ -Y and NaY were compared using Fourier transform infrared (FTIR) spectra, Raman spectroscopy, and ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS). An IR band at 665 cm −1 associated with ν s (Si-O-Cu) was evident for Cu 2+ -Y, which was absent from the spectrum of pure NaY. The Raman bending vibration at 490 cm −1 due to 4-membered ring I in the Cu 2+ -Y displayed a blue shift and a lower value of the full width at half maximum (FWHM) by about 3.02 nm and 0.74 cm −1 , respectively, compared with that of NaY. It was proposed that Cu 2+ ions are attached to shared oxygen of double 4-rings in Y-zeolite. The electronic analysis of Cu 2+ -Y revealed an indirect energy bandgap of 3.17 eV together with an excitonic absorption band at ∼2 eV. The computational molecular adsorption calculations demonstrated the potential effect of Cu 2+ -Y to accommodate five molecules of OTC per unit cell. Molecular dynamics (MD) simulations were committed to support the response behind the higher efficiency and stability of Cu 2+ -Y towards adsorption of the OTC under the force of interaction. OTC molecules brought into being travel toward positions of copper in the optimized OTC@Cu 2+ -Y. In contrast, Na + ions in OTC@NaY held moving towards the edges of the zeolite unit cell and no evidence of the presence of OTC molecules inside the confines of the zeolite cavities. H-bond distribution indicate a close connection and a more stable configuration of OTC inside the Cu 2+ -Y. Thus, MD simulations can safely predict the potential of Cu 2+ to attract the OTC molecules to form OTC@Cu 2+ -Y complexes.

Investigations of Zr/TiO2-based nanocomposites for efficient plasmonic dye-sensitized solar cells

Renewable energy resources have a wide range of materials to fulfill the energy demand. All developed countries are trying to adopt renewable energy resources to overcome the energy crises. Recent research showed that dye-sensitized solar cells (DSSCs) are optimistic and cheap customers for energy purposes. Most used materials in DSSCs are environment-friendly. Zirconium/titanium dioxide-based nanocomposite photoanodes are mostly stable and efficient for DSSCs. SEM, XRD, UV-visible spectroscopy and Raman spectroscopy were employed to check the morphological, structural and optical properties of Cu and Ag-doped Zr/TiO2, respectively. IV measurements investigation showed that due to the Cu and Ag contents’ effects, the power regeneration efficiency was enhanced by 8.18% by using [Formula: see text] of 0.73 V, [Formula: see text] of 8.78 mA cm[Formula: see text], FF 59.03% and IPCE of 62.43%, due to a shortage in recombinations of charge carrier. The carrier transporting mechanism (EIS) was done at a frequency range of 100 mHz to 1 MHz.

Study of Structural and Optical Properties of Cu–Cr Substituted Mg–Co Spinel Ferrites for Optoelectronic Applications

Study of Structural and Optical Properties of Cu–Cr Substituted Mg–Co Spinel Ferrites for Optoelectronic Applications

Highly luminescent copper nanoclusters as temperature sensors and “turn off” detection of oxytetracycline

Polyethyleneimine (PEI), playing roles as a templating agent, has been successfully applied to prepare blue-green-emitting copper nanoclusters (Cu NCs@PEI) on the basis of a rapid chemical reduction synthesis method. Some characterization methods, such as fluorescence spectrophotometer, UV spectrophotometer, Fourier transform infrared instrument (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and fluorescence lifetime, were used for the analysis of physical, chemical and optical properties of Cu NCs@PEI. The Cu NCs@PEI displayed a blue-green emission wavelength at 485 nm and the corresponding quantum yield (QY) was 2.24%. Subsequently, the as-synthesized Cu NCs@PEI were applied for the trace analysis of oxytetracycline on the basis of the inner filter effect (IFE) and static quenching, which caused the fluorescence to be effectively quenched. Additionally, this proposed platform based on the Cu NCs@PEI for oxytetracycline sensing possessed an excellent linear range from 0.5 to 300 μM with a lower detection limit of 0.032 μM (S/N = 3) and correlation coefficient R2 of 0.9972. Surprisingly, as the temperature increased, the fluorescence intensities of Cu NCs@PEI decreased gradually. Thence, the Cu NCs@PEI could be applied for the sensing of temperature. Finally, the practicability of the detection method have been successfully verified by analyzing oxytetracycline in real samples, enlarging its applicable fields for oxytetracycline sensing.

Tailoring Structural and Optical Properties of Cu Doped Chemically Deposited ZnSe Nanostructured Thin Films

Chemical bath deposition has been used for depositing undoped and copper doped ZnSe thin films at 343 K temperature. Growth of the thin film requires zinc sulphate cation and sodium selenosulphate anion. The preparative parameters are optimized with an aim to obtain high quality thin films. Three different concentrations of Cu source are used. XRD pattern indicates the incorporation of copper in to polycrystalline cubic ZnSe in doped thin films and is confirmed by EDAX spectrum. SEM micrographs indicate that ZnSe dispersion in the films is homogeneous. UV–visible transmission spectra of the thin films have put into evidence that the dispersion of ZnSe nanocrystals in the thin film is improved their optical transmission. Room temperature PL spectra have shown that the addition of Cu into ZnSe enhanced the emission with additional green peak other than blue band edge emission. Electrical conductivity also modified on addition of Copper.