Influence Of Cu Doping Research Articles

Influence of Cu doping on the functionality of spray coated SnS2 thin films and its photocatalytic degradation of dyes and antibacterial activity

Tin sulfide (SnS2) is a material known for its effective photocatalytic activity due to its affordability and wide light spectrum response. To enhance and optimize its optical and chemical characteristics, doping is a straightforward approach that can improve its photocatalytic efficiency. This work focuses on the effect of Cu doping on the structural, optical, and photocatalytic properties of the thin films prepared by the spray-coating approach. XRD confirms the hexagonal SnS2 structure. As the amount of Cu added increases, the crystallite size decreases while dislocation density rises. The XPS findings show that a low concentration of copper (2%) within the SnS2 thin films exhibits both high solubility and exclusively a monovalent state, in contrast to the 4% concentration. The effective band gap is in the range of 1.9–2.2 eV. SEM image reveals a variety of morphologies, and the porosity is reduced with increasing Cu doping. Furthermore, the FTIR study confirms the Sn-S bond present at 753 cm−1. EPR studies reveal the existence of sulfur vacancies in Cu-doped SnS2. Mechanical properties were also affected, with an observed decrease in microhardness as the dopant concentration increased. The photocatalytic activity of the samples is studied by photocatalytic degradation of malachite green and Congo red dyes under visible light irradiation. Additionally, their antibacterial effect against Escherichia coli was examined. This study shows that an optimal amount of Cu doping can significantly increase the photocatalytic performance of SnS2 for efficiently decomposing organic pollutants and enhancing antibacterial activities.

Exploring Cu-Doped Co3O4 Bifunctional Oxygen Electrocatalysts for Aqueous Zn-Air Batteries.

The efficiency of oxygen electrocatalysis is a key factor in diverse energy domain applications, including the performance of metal-air batteries, such as aqueous Zinc (Zn)-air batteries. We demonstrate here that the doping of cobalt oxide with optimal amounts of copper (abbreviated as Cu-doped Co3O4) results in a stable and efficient bifunctional electrocatalyst for oxygen reduction (ORR) and evolution (OER) reactions in aqueous Zn-air batteries. At high Cu-doping concentrations (≥5%), phase segregation occurs with the simultaneous presence of Co3O4 and copper oxide (CuO). At Cu-doping concentrations ≤5%, the Cu ion resides in the octahedral (Oh) site of Co3O4, as revealed by X-ray diffraction (XRD)/Raman spectroscopy investigations and molecular dynamics (MD) calculations. The residence of Cu@Oh sites leads to an increased concentration of surface Co3+-ions (at catalytically active planes) and oxygen vacancies, which is beneficial for the OER. Temperature-dependent magnetization measurements reveal favorable d-orbital configuration (high eg occupancy ≈ 1) and a low → high spin-state transition of the Co3+-ions, which are beneficial for the ORR in the alkaline medium. The influence of Cu-doping on the ORR activity of Co3O4 is additionally accounted in DFT calculations via interactions between solvent water molecules and oxygen vacancies. The application of the bifunctional Cu-doped (≤5%) Co3O4 electrocatalyst resulted in an aqueous Zn-air battery with promising power density (=84 mW/cm2), stable cyclability (over 210 cycles), and low charge/discharge overpotential (=0.92 V).

Effect of Cu Doping on Phase Transition, Thermal Strain, and Thermal Expansion Property in Polycrystalline Ni50Mn23−xCuxGa27 Alloys

The influence of Cu doping on phase transition, thermal strain, and thermal expansion property of polycrystalline Ni50Mn23−xCuxGa27(x = 1, 3, 5, 6 and 7) alloys is investigated. The results show that with increasing Cu concentration, martensitic transformation gradually gets close to Curie transition. A magnetostructural transition (MST) is observed in samples with x = 6 and 7. Such MST can enhance magnitude of transformation strain. Besides, Ni50Mn23−xCuxGa27 alloys possess an isotropic, recoverable, and thermally stable thermal strain. Excitedly, Cu doping can effectively tune the phase transition, thermal strain, and thermal expansion properties of Ni50Mn23−xCuxGa27 alloys. Adjustable coefficients of thermal expansion from positive to negative are obtained by Cu‐doped Ni50Mn23−xCuxGa27 alloys. The average linear expansion coefficient (α) between −140.44 and −207.70 ppm K−1 is observed in samples with x = 6 and 7 for a narrow temperature span of 11–14 K. When the temperature span is about 72 K (x = 6) and 73 K (x = 7), which is the largest temperature span observed in Ni–Mn–Ga‐based alloys recently, the α values decrease to about −36 ppm K−1. These findings are beneficial for manipulating the thermal expansion property of Ni–Mn–Ga–Cu alloys and their multifunctional applications.

Influence of Cu doping in Magnesium Hydroxide Nanoparticles for Bandgap Engineering

Influence of Cu doping in Magnesium Hydroxide Nanoparticles for Bandgap Engineering

Synthesis and characterization of pure and Cu-doped WO3 thin films for high performance of toxic gas sensing applications

Oxygen vacancies and the high surface area of nanostructured materials offers stronger gas adsorption active sites for improved gas sensing performance. In the present work, we have deposited WO3-based thin films using a chemical spray pyrolysis technique at a substrate temperature of 400 °C with other optimized preparation parameters. Besides, this study reports the influence of Cu doping at various weight percentages on the structural, morphological, optical and toxic gas sensing properties of WO3 films in detail. The crystalline structure of the material was investigated using the X-ray diffraction technique. Each X-ray diffraction analysis of the films demonstrated a polycrystalline nature, matching the hexagonal phase of WO3 with the (200) plane of preferential orientation of crystal growth. The optical characteristics of the thin film's material were analyzed by UV–Vis absorption spectroscopy. The optical energy bandgap (Eg) of the deposited thin films was estimated using the Tauc relation, and the value was decreased along with the increase in the Cu-doping concentration. The surface roughness of the films has been investigated using atomic force microscopy. The TEM patterns of sprayed Cu-doped WO3 thin films exhibit nanocrystalline features. Detecting toxic gasses is of great importance across the globe due to an alarming enhancement in respiratory, ocular, skin, and lung diseases. Hence, cost-effective and room temperature-operated Cu-doped WO3 thin film sensors to trace low concentrations of toxic gasses have been investigated and systematically reported. It is observed that the sensor response is to be increased with the increase in Cu-doping concentration, particularly the 4 wt.% Cu-doped sensor exhibited a response value of 7.2 and fast response and recovery times in the presence of 50 ppm ammonia vapor.

High performance NIR photodetector based on Cd(1-x)CuxS colloidal quantum dots thin films

Thin films of Cd(1-x)CuxS (x = 0.0 to 0.05 with interval of 0.01) colloidal quantum dots (CQDs) are employed to develop NIR photodetectors (PDs) with significantly high performance parameters and selectivity. Two very cost effective and easy chemical routes are used to synthesize Cd(1-x)CuxS CQDs and to fabricate the PD devices. The Cd(1-x)CuxS CQDs thin films are primarily characterized by various techniques in order to study the influence of Cu doping on different properties of the films. Further, the impact of doping on device performance under the exposure of laser light of different wavelengths is investigated. The tunability in sensing range from visible (635 nm) to NIR (782 nm) of the PDs with a huge improvement in selectivity and device performance due to the incorporation of the dopant is noticed. The maximum selectivity is observed for device S2 (2% Cu in CdS) with maximum responsivity and external quantum efficiency of ∼39 A/W and ∼6.2 × 103% respectively. Whereas the device S4 (4% Cu in CdS) is found to be the fastest with response times of 102 ms/109 ms, sensitivity of ∼3 × 105%, and detectivity of ∼1 × 1014 cmHz1/2W−1. In present study, device S4shows best optimal performance parameters.

First-principle insights of initial hydration behavior affected by copper impurity in alite phase based on static and molecular dynamics calculations

Copper tailings have been used as a raw material for cement clinker production. The Cu element can enter into the cement phase and change its hydration behavior. In this study, the influence of Cu-doping on the structure and hydration characteristics of alite phase (tricalcium silicate, C3S) are disclosed by combining the density functional theory (DFT)-based static and molecular dynamics calculations. In the static simulation, local Oi atoms move closer to doped Cu atom with Cu–O distance of 1.84–1.93 Å and forms Cu-Oi bonds, resulting the decrease of surface electrophilic reactivity. A single water molecule exhibits lower adsorption energies (0.92–2.12 eV) on the Cu-doped C3S surface than on the pure C3S surface (0.62–1.69 eV), as the chemical bonds of Ca-OW and HW-OS were weakened. Further ab-initial molecular dynamics (AIMD) simulations cover the shortcomings of static calculations and obtain new discoveries: (a) Cu-doping promotes hydroxylation of C3S surface and stabilizes fluctuation of dissociated proton. (b) Ca-OW bond concentration is raised after Cu-doping, whereas the constraint effect of the C3S surface on OW is weakened. (c) Cu-doping accelerates the diffusion of Oi into water layer by ∼2 Å within 13 ps, facilitating the dissolution of clinker. These findings contribute in several ways to our understanding of the hydration properties of Cu-doping C3S and provide theoretical support for the sustainable and greener development of the construction industry.

One-step fabrication of Cu-doped Bi2MoO6 microflower for enhancing performance in photocatalytic nitrogen fixation

This study enhances the photocatalytic N2 immobilization performance of Bi2MoO6 through Cu doping. Cu-doped Bi2MoO6 was synthesized via a simple solvothermal method. Various characterizations were implemented to examine the influence of Cu doping on the properties of Bi2MoO6. Results indicated that the doped Cu element had a valence state of + 2 and substituted the position of Bi3+. Cu doping exerted minimal effect on the morphology of Bi2MoO6 but largely influenced the energy band structure. The band gap was slightly narrowed, and the conduction band was raised, such that Cu-doped Bi2MoO6 could generate more electrons with stronger reducibility. Moreover, importantly, Cu doping reduced work function and improved charge separation efficiency, which was considered the major cause of enhanced photoactivity. In addition, the Cu-Bi2MoO6 catalyst exhibited higher capability in the adsorption and activation of N2. Under the combined effects of the aforementioned changes, Cu-Bi2MoO6 demonstrated considerably higher photocatalytic efficiency than Bi2MoO6. The optimized NH3 generation rate reached 302 μmol/L g−1h−1 and 157 μmol/L g−1h−1 under simulated solar light and visible light, respectively, both achieving about 2.2 times higher than that of Bi2MoO6. This work provides a successful example of improving photocatalytic N2 fixation, and it may show some light on the design and preparation of heteroatom-doped semiconductor photocatalysts for N2-to-NH3 conversion.

Influence of Cu doping on the biocompatibility of zirconia-toughened alumina ceramics for artificial joints

Zirconia-toughened alumina (ZTA) is considered the gold standard material for total hip arthroplasty (THA). However, it still lacks sufficient lubrication and fracture toughness, and it has the risk of wearing, squeaking, and fracturing. Cu doping is considered to address these issues. To further promote the application of Cu doping, its effect on biocompatibility needs to be studied. In this study, Cu-doped ZTA (Cu-ZTA) ceramics with different Cu contents were prepared using a fast hot pressed sintering (FHPS) equipment and their biocompatibility was systematically studied. The results demonstrate that, depending on the Cu content, Cu doping reduces the stability of the tetragonal zirconia, resulting in a tetragonal-to-monoclinic phase transition of zirconia, thereby creating pores on the surface of the ZTA. The biocompatibility of the Cu-ZTA with different Cu contents was analyzed based on osteoblasts and macrophages. The results suggested that Cu doping increased the adhesion of osteoblasts and slightly improved their viability. In contrast, Cu doping influenced the morphology of macrophages, causing the shrinkage and extension of their pseudopodia. Cu doping also induced the pro-inflammatory polarization of macrophages and stimulated the secretion of pro-inflammatory cytokines (TNF-α and IL-6). Therefore, Cu doping can improve the cytocompatibility of osteoblasts with ZTA ceramic surfaces, however, the enhanced effect of Cu-doped ZTA ceramics on the early inflammatory response requires special attention and further study.

Emulation of bio-synaptic behaviours in copper-doped zinc oxide memristors: A nanoscale scanning probe microscopic study

Memristors emulating biological synapses to perform memory and learning functions are crucial for realizing bio-inspired neuromorphic systems. However, to meet the increasing demand for high-speed operation, low power consumption, and large integration density in neuromorphic architectures, the synaptic functions must be achieved at nanometer scale and with ultra-low write current. This report evidences electronic synapses realized in Cu-doped ZnO (CZO) memristors by nanoscale scanning probe microscopic techniques. In this process, the device can be downsized all the way up to the size of the probe, offering ultra-high density (>109 devices/mm2) of electronic synapses. The essential bio-synaptic functions in the memristor are accomplished with ultra-low write current (∼10 nA) and in a forming-free approach that marks their potential in building power-efficient computing systems. The modulation in device conductivity is elucidated on the basis of charged defect migration, forming conducting bridges across the thickness or locally within the CZO layer. In addition, the influence of Cu-doping in controlling nanoscale neuromorphic and memristive performances of the device is explored. The present study, therefore, demonstrates a novel approach to decipher oxide-based synaptic-memristors and highlights CZO as a promising candidate to fabricate ultra high-density power-efficient neuromorphic devices.

Hybrid Density Functional Investigation of Cu Doping Impact on the Electronic Structures and Optical Characteristics of TiO2 for Improved Visible Light Absorption.

We report a theoretical investigation of the influence of Cu doping into TiO2 with various concentrations on crystal structure, stability, electronic structures and optical absorption coefficient using density functional theory via the hybrid formalism based on Heyd Scuseria Ernzerhof. Our findings show that oxygen-rich environments are better for fabricating Cu-doped materials and that the energy of formation for Cu doping at the Ti site is lower than for Cu doping at the O site under these environments. It is found that Cu doping introduces intermediate bands into TiO2, narrowing the band gap. Optical absorption curves show that the Cu-doped TiO2 can successfully harvest visible light. The presence of widely intermediate bands above the valence-band edge could explain the increase in the visible light absorption range. However, the intensity of visible light absorption rises with the increase in doping concentration.

Platinum nanoparticles deposited on Cu-doped NiO/C hybrid supports as high-performance catalysts for ethanol and glycerol electrooxidation in alkaline medium

In this work, the influence of Cu-doping on the ability of NiO co-catalyst to enhance the electrocatalytic properties of carbon-supported Pt nanoparticles toward ethanol and glycerol oxidation was investigated. The Cu-doped NiO particles were synthesized by a precipitation method, while the noble metal nanoparticles were deposited over the hybrid Cu-doped NiO/C supports via a pulsed microwave-assisted polyol method using ethylene glycol as reductant. Pt-NiO and Pt-NiOCuO(x:y)/C catalysts with Ni:Cu atomic ratios of 9:1 (Pt-NiOCuO(9:1)/C), 7:3 (Pt-NiOCuO(7:3)/C) and 5:5 (Pt-NiOCuO(5:5)/C) were obtained. The physicochemical analysis showed that the as-prepared catalysts are composed of nanoparticles of about 3 nm. The potentiostatic experiments exhibited that the Pt-NiOCuO(7:3)/C catalyst is the most active catalyst for ethanol oxidation, while the Pt-NiOCuO(5:5)/C catalyst exhibited the best performance for glycerol oxidation. These catalysts developed mass current densities of almost 12 and 5 times higher than those of bare Pt/C for ethanol and glycerol oxidation reactions, respectively. Moreover, an accelerated multicycling stability test displayed that the as-prepared catalysts retain almost 98% of their initial mass current density.

Microtexture analysis of copper-doped iron oxide thin films prepared by air pneumatic spray.

The stereometric and fractal concepts are crucial tools to analyse, to verify, to report 3-D microtexture of thin film surfaces on the nanometre scale and thereby to generate useful topographic characteristics for better understanding and steering them toward further improvements and rational use in modern applications. At first, the present work aimed to prepare hematite α-Fe2 O3 thin films with (0, 2, 4, 6 and 8 wt%) of Cu doping by using the air pneumatic spray method. Subsequently, the obtained pure α-Fe2 O3 and Cu-doped α-Fe2 O3 thin films were characterised by XRD device, which determines their polycrystalline nature with the rhombohedral hematite structure. Analysis by UV-VIS absorption showed that the transmittance of the thin films is extinct in the wavelength from approximately 500 to 800 nm, revealing that the films have good optical absorbance in the visible region. The obtained bandgap values varied between 2.23 and 2.21 eV. At second stage, the stereometric and fractal analysis are applied on 3-D image data of pure α- Fe2 O3 and Cu-doped α-Fe2 O3 thin films, which in prior generated using AFM device. Accordingly, the obtained statistical parameters such as surface roughness, density distribution of peaks, depths etc. were used to understand the influence of Cu doping on the 3D microtexture of pure α- Fe2 O3 and Cu-doped α- Fe2 O3 thin film surfaces.

Influence of Cu Doping on the Hydration of Dicalcium Silicate: A First-Principles Study

Influence of Cu Doping on the Hydration of Dicalcium Silicate: A First-Principles Study

Influence of Cu-doped TiO2 on its structural and photocatalytic properties

Due to the potential of heterogeneous photocatalysis for wastewater treatment, the researches concerning the improvement materials modifications for its photocatalytic activity have been widely increased. One of the most employed methods is the metal doping into semiconductors. Herewith, we demonstrated the influence of Cu doping into TiO2 in its photocatalytic properties. The powder samples with 0.0 to 0.7% mol were obtained by the Pechini method and characterized by XRD, micro-Raman spectroscopy, FE-SEM, and photoluminescence spectroscopy. The Cu insertion into TiO2 structure induced the stabilization of anatase phase, increasing its content in the samples in relation to the bare TiO2. The PL results indicated that a decrease in the PL emission intensity and a shift of the emission band to the blue region. The photocatalytic activity for rhodamine B degradation under UV light irradiation indicated that the Cu-doping into TiO2 led to an enhancement of the photocatalytic activity compared to the bare one.

Influence of Cu Doping on the Material Properties and Antibacterial Activity of Green Synthesized Ceria Nanoparticles

Influence of Cu Doping on the Material Properties and Antibacterial Activity of Green Synthesized Ceria Nanoparticles

Dewetted Silver Nanoparticle-Dispersed WO3 Heterojunction Nanostructures on Glass Fibers for Efficient Visible-Light-Active Photocatalysis by Magnetron Sputtering.

Fabrication of hybrid-heterojunction nanostructures comprising the Z-scheme and localized surface plasmon resonance is essential for enhancing the photocatalytic degradation of organic compounds to enable environmental remediation. This study focuses on the dispersion of dewetted Ag nanoparticles over the 3D network-like silica glass fibers (SGFs) coated with a Cu-doped WO3 heterojunction system by a high-throughput and cost-effective method using magnetron sputtering, followed by solid-state dewetting. The influence of Cu doping on the crystal structure, growth direction, and morphology of WO3 and the effect of localized surface diffusion-driven dewetted Ag nanoparticles on the photocatalytic performance were investigated. The Cu doping changed the optical band gap, and the 2Cu–WO3/SGF exhibited excellent photocatalytic activity. The surface dispersion of dewetted Ag nanoparticles over Cu–WO3/SGFs exhibited lowest photoluminescence intensity, indicating the effective separation of photogenerated electrons–holes, which led to highest efficiency (∼98%) in photocatalytic degradation of methylene blue among all the fibers with a degradation rate constant (k = 0.0205 min–1) that was ∼18.6 times higher than that of pure WO3 (k = 0.0011 min–1). The findings of this study can provide insights for designing low-cost and efficient visible-light-active photocatalysts for organic dye degradation, enabling environmental remediation.

Influence of Cu doping on structure, morphology and optical characteristics of SnO2 thin films prepared by chemical bath deposition technique

This paper reports various properties of four Cu-doped SnO2 thin films (hereafter called CuSnO-TFs) synthesized on glass substrate at temperature 80 °C via the standard chemical bath deposition method. The as-deposited films were annealed at 400 °C for 1 h. The as-prepared samples were characterized at room temperature using different analytical tools to determine the effects of varying Cu doping contents (0–3 wt%) on their structures, morphologies, and optical characteristics. The XRD analyses of the studied CuSnO-TFs showed their body-centered tetragonal structures in rutile phase with high purity and good polycrystallinity. The average crystallite size was increased from 17.6 to 34.52 nm with the increase of Cu contents from 0 to 3%, respectively. The SEM images of the grown films revealed agglomerated morphologies with the nucleation of spherical clusters or granules. Both visible transmittance and optical band gap energies of the films were decreased with the increase of Cu levels. In addition, the values of the refractive index, extinction coefficient, and dielectric constant of the deposited films were gradually increased and shifted towards higher wavelengths with the increase of Cu doping proportion. It was shown that by tuning the Cu contents overall properties of the proposed SnO2 thin films can be customized which are desired for diverse functional applications.

Influence of Cu doping on physical and photo-electrochemical properties of CdS thin films prepared by RF magnetron sputtering

In this paper, Cu doped CdS thin films were prepared on FTO substrates by RF magnetron sputtering and then were annealed at 350 °C–425 °C in vacuum for 20 min. The influences of different Cu-doped concentrations (Cu 4.1, 5.4, 7.3, 9.1 at%) on morphological, structural, optical properties and photo-electrochemical (PEC) properties of CdS thin films were investigated. The PEC characterizations indicated that the photocurrent densities of CdS:Cu (Cu 4.1, 5.4, 7.3, 9.1 at%) thin films increased from 0.94, 1.28,1.86,1.91 mA cm−2 to 1.33, 1.89, 2.40, 3.16 mA cm−2 after annealing. And the PEC properties of CdS:Cu thin films annealed at different temperatures were also studied. FTO/annealed CdS:Cu/Pt photoanode were fabricated to enhance the photocurrent activity and the photocurrent density of FTO/annealed CdS:Cu/5 nm Pt is 1.5 times larger than that of the CdS:Cu electrode without Pt cocatalyst.

A systematic influence of Cu doping on structural and opto-electrical properties of fabricated Yb2O3 thin films for Al/Cu-Yb2O3/p-Si Schottky diode applications

In the present work, transition metal doped rare earth metal oxide (Cu-Yb2O3) thin films have been effectively synthesized on a large scale using low-cost jet nebulizer spray pyrolysis (JNSP) route at different copper (Cu) doping concentrations (0, 1.5, 2.5, 3.5, and 4.5 wt%) with optimized substrate temperature of 550 °C. The structural, morphological and opto-electrical properties were investigated using various characterization techniques. The X-ray diffraction (XRD) profile indicates the polycrystalline nature of all the deposited films with a cubic phase and the size of crystallites is found to increase from 11 to 31 nm. The field emission scanning electron microscope (FESEM) images reveal that the Cu doping has significant impact on the surface morphology of Cu-Yb2O3 films. The atomic force microscope (AFM) analysis exposed higher roughness value for 4.5 wt% of Cu-Yb2O3 films. The elemental composition study approves the presence of Yb, Cu and O in the film. The transmittance and indirect optical energy gap of Cu-Yb2O3 films have been analyzed by UV–Visible spectroscopy which established the systematic band gap reduction of Yb2O3 thin films from 3.68 to 3.14 eV with increasing Cu concentrations. The DC electrical studies showed a maximum conductivity and minimum average activation energy for 4.5 wt% of Cu-Yb2O3 film. The electrical characteristics of the fabricated Al/Cu-Yb2O3/p-Si Schottky diode was investigated using current–voltage (I-V) measurements performed under dark and light conditions. The ΦB (0.911 eV in dark & 0.754 eV in illumination) and minimum n values (2.120 in dark and 1.757 in illuminations) were obtained for MIS diode having Cu doping concentration of 4.5 wt% in Yb2O3.