ZnO Core Shell Research Articles

Novel nanostructure approach for antibiotic decomposition in a spinning disc photocatalytic reactor

Conventional wastewater treatment processes are often unable to remove antibiotics with resistant compounds and low biological degradation. The need for advanced and sustainable technologies to remove antibiotics from water sources seems essential. In this regard, the effectiveness of a spinning disc photocatalytic reactor (SDPR) equipped with a visible light-activated Fe3O4@SiO2-NH2@CuO/ZnO core–shell (FSNCZ CS) thin film photocatalyst was investigated for the decomposition of amoxicillin (AMX), a representative antibiotic. Various characterization techniques, such as TEM, FESEM, EDX, AFM, XRD, and UV–Vis-DRS, were employed to study the surface morphology, optoelectronic properties, and nanostructure of the FSNCZ CS. Key operating parameters such as irradiation time, pH, initial AMX concentration, rotational speed, and solution flow rate were fine-tuned for optimization. The results indicated that the highest AMX decomposition (98.7%) was attained under optimal conditions of 60 min of irradiation time, a rotational speed of 350 rpm, a solution flow rate of 0.9 L/min, pH of 5, and an initial AMX concentration of 20 mg/L. Moreover, during the 60 min irradiation time, more than 69.95% of chemical oxygen demand and 61.2% of total organic carbon were removed. After the photocatalytic decomposition of AMX, there is a substantial increase in the average oxidation state and carbon oxidation state in SDPR from 1.33 to 1.94 and 3.2, respectively. Active species tests confirmed that ·OH and ·O2− played a dominant role in AMX decomposition. The developed SDPR, which incorporates a reusable and robust FSNCZ CS photocatalyst, demonstrates promising potential for the decomposition of organic compounds.

Inclusion of metal nanoparticles at the core-shell interface of GaAs0.99Bi0.01/ZnO/ITO core-shell nanowire solar cell for photovoltaic performance enhancement

Optoelectronic performance analysis of perpendicularly aligned conformally coated GaAs0.99Bi0.01/ZnO/ITO core–shell nanowire solar cell having a core length of 1 μm, core diameter of 160 nm, shell thickness of 10 nm and period of 280 nm, decorated with Au metal nanoparticles(MNPs) of variable diameters at the core–shell interface is done employing FDTD method. Diameter optimization of MNPs with four different diameters values around core GaAs0.99Bi0.01 nanowire is accomplished in terms of maximum short circuit current density (Jsc), which offered an optimized diameter combination of D1 = D2 = 50 nm and D3 = 34 nm, D4 = 10 nm, resulting in a maximum Jsc of 32.6 mA cm−2. A detailed analysis of the electric field profile including its top view and longitudinal view is presented to investigate the distribution of electric field upon optical illumination at different wavelength range. The overall photo generation rate profile is also presented to focus on the localized surface plasmon resonance effect caused by the metal nanoparticles (MNPs). In order to boost the electrical performance, a thin coating of electron selective ZnO shell is used around p type GaAs0.99Bi0.01core, which aids in charge carrier separation, thereby improving open circuit voltage (Voc) and overall power conversion efficiency (PCE). The electrical characteristics of bare NW and MNP decorated GaAs0.99Bi0.01/ZnO core–shell nanowire solar cell for different MNP diameters have been compared. For the optimized diameter combination, as stated above, a Voc of 941 mV, Jsc of 28 mA cm−2, FF of 84.35% and PCE of 22.19% is obtained for SRV of 105 cm s−1 at the interfaces and SRH recombination lifetime as less as 10 ns. For SRV of 105 cm s−1 at the interfaces and SRH recombination lifetime of 1 μs, this proposed structure can achieve a Voc of 1.06 V, Jsc of 31.5 mA cm−2, PCE of 29.37% and FF of 87.88% for equal diameters of D1 = D2 = D3 = D4 = 50 nm.

Charge transfer induced linear and nonlinear optical properties in polypyrrole/ZnO@MoS2 ternary composites

Polymer-based ternary nanocomposites with tunable optical properties are the key components for optoelectronics applications. Here, we demonstrate the linear and nonlinear optical properties of polypyrrole (PPy) and its ternary composites with different concentrations of the MoS2–ZnO core–shell (ZnO@MoS2) heterostructure. The interesting observation of multiple excitons and their transportation through the interface of PPy and ZnO@MoS2 by using photoluminescence and fluorescence lifetime spectroscopy was studied. Furthermore, the third-order nonlinear optical properties of all samples were also measured by employing the z-scan technique at an excitation wavelength of 532 nm. The reverse saturable absorption of pure PPy was switched to saturable absorption after the addition of ZnO@MoS2 at the uniform linear transmittance. These ternary composites with good nonlinear responses provide an option for the development of high-performance nonlinear optical devices and open a new path for the future development of ternary systems in the optical fields.

Effect of structure of ZnO and SiO2 core-shell composite nanoparticles as lubricant additive on tribological properties of greases

Nano-additives can enhance the tribological properties of greases. In particular, core-shell composite nanoparticles, which combine multiple nanoparticles, have been the subject of recent research due to their superior properties. In this study, based on the friction pairs material, GCr15, by choosing ZnO with low hardness and SiO2 with high hardness, core-shell composite nanoparticles with soft shell hard core SiO2@ZnO and hard shell soft core ZnO@SiO2 were prepared by chemical deposition and calcination methods. The impact of different structural forms of these composite nanoparticles as grease additives were investigated for the first time by adding them into lithium grease. The results show that ZnO@SiO2 have good tribological properties under light load, reducing the COF by 18 % and decreasing the WSD by 22 %. SiO2@ZnO exhibit the best anti-friction effect under heavy load conditions, reducing the COF by 15 % and decreasing the WSD by 28 %. The GCr15-ZnO-SiO2 surface composite film structure is the key to improve the performance of grease in the two composite nanoparticles. It not only has good wear resistance, but also can increase the bearing capacity of the oil film. The two core-shell structure nano-additives provide a new idea for the design of lubricants under special conditions.

Synthesis of AZO-Coated ZnO Core-Shell Nanorods by Mist Chemical Vapor Deposition for Wastewater Treatment Applications.

AZO-coated ZnO core-shell nanorods were successfully fabricated using the mist chemical vapor deposition method. The influence of coating time on the structural, optical, and photocatalytic properties of zinc oxide nanorods was investigated. It was observed that the surface area of AZO-coated ZnO core-shell nanorods increased with an increase in coating time. The growth orientation along the (0001) crystal plane of the AZO thin film coating was the same as that of zinc oxide nanorods. The crystallinity of AZO-coated ZnO core-shell nanorods was significantly improved as well. The optical transmittance of AZO-coated ZnO core-shell nanorods was greater than 55% in the visible region. The degradation efficiency for methyl red dye solution increased with an increase in coating time. The highest degradation efficiency was achieved by AZO-coated ZnO core-shell nanorods with a coating duration of 20 min, exhibiting a degradation rate of 0.0053 min-1. The photodegradation mechanism of AZO-coated ZnO core-shell nanorods under ultraviolet irradiation was revealed.

Synthesis of core–shell ZnO nanoparticles and their effect on mechanical and antibacterial properties for PLLA/ZnO nanocomposites

AbstractTo overcome the inherent brittleness of renewable poly(l‐lactide) acid (PLLA) and enable it for use in a wide application, we successfully synthesized the toughening agent of ZnO nanoparticles grafted by poly(caprolactone‐co‐d‐lactide) (ZnO‐g‐PCLDLA) via sequential open‐loop polymerization. First, ZnO was silanized to produce hydroxyl groups on the surface of the nanoparticles. Initiated by hydroxyl groups on the ZnO core, the rubbery PCLDLA composed of caprolactone‐d‐lactide co‐polymeric segments and d‐lactide homo‐polymeric segments was successively polymerized, forming ZnO core–shell nanoparticles. PLLA/ZnO‐g‐PCLDLA nanocomposites were prepared by solution blending. The nanocomposites with 10 wt% ZnO‐g‐PCLDLA exhibited superior ductility, whose elongation at break was about 54 times higher than that of neat PLLA. This considerable increment of toughness was attributed to the rubbery shell of PCLDLA and the enhanced interfacial interaction from the interfacial stereocomplex crystallites, formed by co‐crystallization of the PLLA matrix and d‐lactide homo‐polymeric segments of the PCLDLA shell on ZnO. The PLLA/ZnO‐g‐ PCLDLA nanocomposite films possessed outstanding antimicrobial properties against Staphylococcus aureus and Escherichia coli. Positive ZnO produces an electrostatic force to interact with the negatively charged membrane of bacteria, thereby damaging the cell membrane and achieving significant antibacterial effects.Highlights ZnO‐g‐PCLDLA core–shell nanoparticles were constructed by sequential ROP. The ZnO core provided high rigidity and antimicrobial properties. The rubbery PCLDLA shell provided high elasticity and ductility. Interfacial interaction was greatly enhanced by the SC crystallites. The PLLA nanocomposite films exhibited outstanding antimicrobial activity.

The advancing of polymeric core-shell ZnO nanocomposites containing 5-fluorouracil for improving anticancer activity in colorectal cancer.

The study investigated the use of 5-fluorouracil-loaded ZnO nanocomposites (5-FU/Gd-ZnO NCs) as a potential treatment for cancer. 5-FU is a commonly used drug for cancer treatment but has undesirable side effects. The materials were characterized using various techniques, including PXRD, FTIR, FESEM, TEM, DLS, £-potential, and AFM. The data showed that the nanocomposites had a plate-like agglomeration with particle diameters ranging from 317.6 to 120.1nm. The IC50 value of 5-FU-ZnO, which inhibits cell growth, was found to be 1.85ppm. The effects of 5-FU-ZnO on inflammatory markers were also examined. While 5-FU increased the levels of TNF-a and IL-1b, the nanocomposites were able to reduce these levels. Additionally, the 5-FU/Gd-ZnO-NCs group showed an increase in thiol levels and a decrease in catalase and superoxide dismutase levels. Flow cytometry results showed that 5-FU, ZnO-NCs, and 5-FU/Gd-ZnO-NCs did not have any additive or synergistic effects on the suppression or eradication of cancer cells. In vivo, experiments showed that the 5-FU/Gd-ZnO NCs had similar necrotic characteristics and reduced fibrosis and collagen deposition compared to the free medication. The nanocomposites also exhibited higher antioxidative activity and lower inflammatory responses compared to the 5-FU group. It was shown that 5-FU/Gd-ZnO-NCs successfully inhibit cell proliferation. The in vivo results were comparable to those obtained with free 5-FU, suggesting the potential of these nanocomposites as therapeutic agents.

Evaluation of Antimicrobial Agents of Ag–ZnO Core-Shell Prepared by Micro-Jet Plasma Technique

Atmospheric pressure Micro-jet plasma technique is used in this study to create Ag–ZnO core/shell nanoparticles. Several different methods, including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and ultraviolet-visible spectroscopy (UV–Vis), confirmed the characterization of the synthesized Ag–ZnO core/shell nanoparticles. The pureness of these nanoparticles was validated by XRD analysis, which showed no peaks associated with secondary phases for Ag–ZnO. The synthesis of very pure Ag–ZnO core/shell nanoparticles was also verified by EDX analysis. To understand the high agglomeration rate, the surface morphology was studied by FE-SEM. The Ag–ZnO core/shell nanoparticles were measured to be between 20 and 60[Formula: see text]nm in size by transmission electron microscopy. Ag–ZnO core/shell nanoparticles showed energy band gaps of 3.22[Formula: see text]eV. After that, the antibacterial activity of the prepared nanoparticles was tested against two different types of Gram-positive bacteria [Formula: see text]Staphylococcus. epidermidis and Staphylococcus aureus[Formula: see text] and two different types of Gram-negative bacteria [Formula: see text]Klebsiella. pneumonia and Escherichia coli[Formula: see text] that were isolated from the oral cavity. Additionally, the antifungal activity of the prepared nanoparticles was tested against two different types of yeast [Formula: see text]Candida[Formula: see text]. Antimicrobial activity was shown by the Ag–ZnO nanoparticles produced using the micro-jet plasma method, and the findings suggested that these nanoparticles may be used to eliminate dangerous and harmful bacteria and fungi.

Fabrication of CuO (p)–ZnO (n) Core–Shell Nanowires and Their H2-Sensing Properties

Unlike the conventional one-dimensional (1D) core–shell nanowires (NWs) composed of p-type shells and n-type cores, in this work, an inverse design is proposed by depositing n-type ZnO (shell) layers on the surface of p-type CuO (core) NWs, to have a comprehensive understanding of their conductometric gas-sensing kinetics. The surface morphologies of bare and core–shell NWs were investigated by field emission scanning electron microscope (FE-SEM). The ZnO shell layer was presented by overlay images taken by electron dispersive X-ray spectroscopy (EDX) and high-resolution transmission electron microscopy (HRTEM). The pronounced crystalline plane peaks of ZnO were recorded in the compared glancing incident X-ray diffraction (GI-XRD) spectra of CuO and CuO–ZnO core–shell NWs. The ZnO shell layers broaden the absorption curve of CuO NWs in the UV-vis absorption spectra. As a result of the heterostructure formation, the intrinsic p-type sensing behavior of CuO NWs towards 250 and 500 ppm of hydrogen (H2) switched to n-type due to the deposition of ZnO shell layers, at 400 °C in dry airflow.

Zeolitic imidazolate framework-derived ZnO polyhedrons wrapped by Co nanoparticle embedded in N-doped carbon for high-performance lithium and potassium storage

Metal oxides are considered as promising anodes for alkali-ion batteries due to their high theoretical capacity and moderate volume expansion. However, they still suffer from the low electrical conductivity and capacity decay, resulting poor rate capability and cyclic stability. In this work, core-shell ZnO polyhedrons coated by Co nanoparticle embedded in N-doped carbon (ZnO@Co/NC) were prepared via a convenient route using zeolitic imidazolate frameworks as precursors. The unique structural design not only synergistically forms a three-dimensional conductive network to promote the transfer and storage of Li+/K+ ions, but also restrains the volume changes of ZnO polyhedron during repeated lithiation/potassiation processes, contributing to enhanced lithium and potassium storage performances. The ZnO@Co/NC anode delivers 458.3 mAh g−1 after 1000 cycles at an ultrahigh current density of 10 A g−1 with a capacity retention of 95% for LIBs, and remains 181.5 mAh g−1 after 1000 cycles at 200 mA g−1 with 84% retention for KIBs. When coupled with commercial LiFePO4 cathode, the full cell delivers a capacity of 140.6 mAh g−1 after 250 cycles at 1 A g−1. This work not only shows the promising potential ZnO-based materials for long-term and high-rate lithium-ion batteries, but also gives an insight into the design of ZnO-based anodes for potassium storage.

The advance anticancer role of polymeric core-shell ZnO nanoparticles containing oxaliplatin in colorectal cancer.

We evaluated the activity of core-shell ZnO nanoparticles (ZnO-NPs@polymer shell) containing Oxaliplatin via polymerization through in vitro studies and in vivo mouse models of colorectal cancer. ZnO NPs were synthesized in situ when the polymerization step was completed by co-precipitation. Gadolinium coordinated-ZnONPs@polymer shell (ZnO-Gd NPs@polymer shell) was synthesized by exploiting Gd's oxophilicity (III). The biophysical properties of the NPs were studied using powder X-ray diffraction (PXRD), Fourier transforms infrared spectroscopy, Ultraviolet-visible spectroscopy (UV-Vis), field emission electron microscopy (FESEM), transmission electron microscopy (TEM), atomic force microscopy, dynamic light scattering, and z-potential. (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) was used to determine the antiproliferative activity of ZnO-Gd-OXA. Moreover, a xenograft mouse model of colon cancer was exerted to survey its antitumor activity and effect on tumor growth. In the following, the model was also evaluated by histological staining (H-E; Hematoxylin & Eosin and trichrome staining) and gene expression analyses through the application of RT-PCR/ELISA, which included biochemical evaluation (MDA, thiols, SOD, CAT). The formation of ZnO NPs, which contained a crystallite size of 16.8 nm, was confirmed by the outcomes of the PXRD analysis. The Plate-like morphology and presence of Pt were obtained in EDX outcomes. TEM analysis displayed the attained ZnO NPs in a spherical shape and a diameter of 33 ± 8.5 nm, while the hydrodynamic sizes indicated that the particles were highly aggregated. The biological results demonstrated that ZnO-Gd-OXA inhibited tumor growth by inducing reactive oxygen species and inhibiting fibrosis, warranting further research on this novel colorectalcancer treatment agent.

Oxygen Adsorption on Polar and Non-Polar Zn:ZnO Heterostructures from First Principles.

Zn:ZnO nanostructures have been studied extensively due to their potential use in many applications, such as oxygen scavengers for food packaging applications. Under atmospheric conditions, ZnO grows on the surface of Zn via an oxidation process. The mechanisms governing Zn oxidation are still not fully understood, with classical oxidation models, such as the Cabrera Mott, underestimating the oxide thickness of Zn:ZnO core-shell structures. In this work, Ab initio DFT calculations were performed to assess the adsorption properties of oxygen molecules on Zn:ZnO heterostructures to help elucidate the mechanisms involved in the growth of a ZnO film on a Zn substrate. Results suggest that the charge transfer mechanism from the Zn:ZnO heterostructures to the adsorbed oxygen layer can be promoted by two different processes: the electronic doping of ZnO due to the formation of the Zn:ZnO interface and the excess surface charge due to the presence of dangling bonds on the as cleaved ZnO.

The effect of different rates of ultra-thin gossamer-like rGO coatings on photocatalytic performance in ZnO core-shell structures for optoelectronic applications

In the study, core-shell-structured Al/(ZnO:rGO)/pSi/Al photo-diodes were successfully fabricated using a sol-gel spin-coating method by varying the concentration of reduced-graphene oxide (rGO) from 1 % to 9 % (wt). The ZnO:rGO composite solution was coated on a silicon (p-Si) wafer at 1000 rpm and 300 K. Both aluminum back-ohmic and front-rectifier contacts were performed on the p-Si wafer by physical-vapor-deposition (PVD). The morphological and chemical structure of the photo-diodes were determined by using field-emission scanning electron microscopy (FE-SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). The current-voltage (I-V) analysis in dark and under ultraviolet (UV, 365 nm) wavelength was utilized in detail. Basic electrical parameters, including the ideality factor (n), barrier height (BH) and series-shunt resistances (R s , R sh ), were calculated using a variety of methods and compared to each other. The Card-Rhoderick method was used to extract energy-dependent profiles of interface traps (N ss ). The core-shell-structured (ZnO-7 % rGO) photo-diode exhibited the best photocatalytic performance both in dark and under various illumination intensities (50–250 mW/cm 2 ). The ZnO:rGO interlayer at the metal-semiconductor (M/S) interface leads to improvement of the photo-diode in respect of low-ideality factor/Nss/leakage-current and high-rectification and BH. • The ZnO:rGO core-shell structures were synthesized and coated successfully and homogeneously using sol-gel spin coating. • This study is pioneer due to the fact that there is no detailed study about the Al/ZnO:rGO/pSi/Al photo-diodes from ZnO:rGO interface as wrapped different rGO rates ZnO core-shell. • The rGO nanosheets were provided bridging and this may be a conductivity mechanism between ZnO spheres that increases the conductivity of the photo-diodes. • The 7 % rGO included ZnO core-shell structure has a strongly positive effect on the photo-diode performance. • The 7 % rGO included ZnO:rGO interlayer can be succesfully used instead of traditional insulator layer in the future.

L-cysteine embedded core-shell ZnO microspheres composed of nanoclusters enhances anticancer activity against liver and breast cancer cells

Nano-based products have become an apparent and effective option to treat liver cancer, which is a deadly disease, and minimize or eradicate these problems. The Core-shell ZnO microspheres composed of nanoclusters (ZnOMS-NCs) have shown that it is very worthwhile to administer the proliferation rate in HepG2 and MCF-7 cancer cells even at a very low concentration (5 μg/mL). ZnOMS-NCs were prepared through hydrothermal solution process and well characterized. The MTT assay revealed that the cytotoxic effects were dose-dependent (2.5 μg/mL-100 μg/mL) on ZnOMS-NCs. The diminished activity in cell viability induces the cytotoxicity response to the ZnOMS-NCs treatment of human cultured cells. The qPCR data showed that the cells (HepG2 and MCF-7) were exposed to ZnOMS-NCs and exhibited up-and downregulated mRNA expression of apoptotic and anti-apoptotic genes, respectively. In conclusion, flow cytometric data exhibited significant apoptosis induction in both cancer cell lines at low concentrations. The possible mechanism also describes the role of ZnOMS-NCs against cancer cells and their responses.

Spraying Core–Shell ZnO To Achieve High Insulation Performance for HVDC Cable Factory Joints

Spraying Core–Shell ZnO To Achieve High Insulation Performance for HVDC Cable Factory Joints

Self-connected CuO–ZnO radial core–shell heterojunction nanowire arrays grown on interdigitated electrodes for visible-light photodetectors

An original photodetector system based on self-connected CuO–ZnO radial core–shell heterojunction nanowire arrays grown on metallic interdigitated electrodes, operating as visible-light photodetector was developed by combining simple preparation approaches. Metallic interdigitated electrodes were fabricated on Si/SiO2 substrates using a conventional photolithography process. Subsequently, a Cu layer was electrodeposited on top of the metallic interdigitated electrodes. The CuO nanowire arrays (core) were obtained by thermal oxidation in air of the Cu layer. Afterwards, a ZnO thin film (shell) was deposited by RF magnetron sputtering covering the surface of the CuO nanowires. The morphological, structural, compositional, optical, electrical and photoelectrical properties of the CuO nanowire arrays and CuO–ZnO core–shell nanowire arrays grown on metallic interdigitated electrodes were investigated. The performances of the devices were evaluated by assessing the figures of merit of the photodetectors based on self-connected CuO–ZnO core–shell heterojunction nanowire arrays grown on the metallic interdigitated electrodes. The radial p–n heterojunction formed between CuO and ZnO generates a type II band alignment that favors an efficient charge separation of photogenerated electron–hole pairs at the CuO–ZnO interface, suppressing their recombination and consequently enhancing the photoresponse and the photoresponsivity of the photodetectors. The electrical connections in the fabricated photodetector devices are made without any additional complex and time-consuming lithographic step through a self-connecting approach for CuO–ZnO core–shell heterojunction nanowire arrays grown directly onto the Ti/Pt metallic interdigitated electrodes. Therefore, the present study provides an accessible path for employing low dimensional complex structures in functional optoelectronic devices such as photodetectors.

Improved Photoresponse Characteristics of a ZnO-Based UV Photodetector by the Formation of an Amorphous SnO2 Shell Layer

Although ZnO nanostructure-based photodetectors feature a well-established system, they still present difficulties when being used in practical situations due to their slow response time. In this study, we report on how forming an amorphous SnO2 (a-SnO2) shell layer on ZnO nanorods (NRs) enhances the photoresponse speed of a ZnO-based UV photodetector (UV PD). Our suggested UV PD, consisting of a ZnO/a-SnO2 NRs core–shell structure, shows a rise time that is 26 times faster than a UV PD with bare ZnO NRs under 365 nm UV irradiation. In addition, the light responsivity of the ZnO/SnO2 NRs PD simultaneously increases by 3.1 times, which can be attributed to the passivation effects of the coated a-SnO2 shell layer. With a wide bandgap (~4.5 eV), the a-SnO2 shell layer can successfully suppress the oxygen-mediated process on the ZnO NRs surface, improving the photoresponse properties. Therefore, with a fast photoresponse speed and a low fabrication temperature, our as-synthesized, a-SnO2-coated ZnO core–shell structure qualifies as a candidate for ZnO-based PDs.

Core-Shell ZnO@Cu2O as Catalyst to Enhance the Electrochemical Reduction of Carbon Dioxide to C2 Products

The copper-based catalyst is considered to be the only catalyst for electrochemical carbon dioxide reduction to produce a variety of hydrocarbons, but its low selectivity and low current density to C2 products restrict its development. Herein, a core-shell xZnO@yCu2O catalysts for electrochemical CO2 reduction was fabricated via a two-step route. The high selectivity of C2 products of 49.8% on ZnO@4Cu2O (ethylene 33.5%, ethanol 16.3%) with an excellent total current density of 140.1 mA cm−2 was achieved over this core-shell structure catalyst in a flow cell, in which the C2 selectivity was twice that of Cu2O. The high electrochemical activity for ECR to C2 products was attributed to the synergetic effects of the ZnO core and Cu2O shell, which not only enhanced the selectivity of the coordinating electron, improved the HER overpotential, and fastened the electron transfer, but also promoted the multielectron involved kinetics for ethylene and ethanol production. This work provides some new insights into the design of highly efficient Cu-based electrocatalysts for enhancing the selectivity of electrochemical CO2 reduction to produce high-value C2 products.

Preparation of single crystalline AlN thin films on ZnO nanostructures by atomic layer deposition at low temperature

The growth of hetero-epitaxial ZnO-AlN core–shell nanowires (NWs) and single crystalline AlN films on non-polar ZnO substrate at temperature of 380 °C by atomic layer deposition (ALD) was investigated. Structural characterization shows that the AlN shells have excellent single-crystal properties. The epitaxial relationship of [0002]ZnO//[0002]AlN, and [10−10]ZnO//[10−10]AlN between ZnO core and AlN shell has been obtained. The ZnO NW templates were subsequently removed by annealing treatment in forming gas, resulting in ordered arrays of AlN single-crystal nanotubes. The impact factors on the epitaxial growth of AlN films are thoroughly investigated. It turned out that the growth parameters including lattice mismatch between substrate and AlN, growth temperature, and the polarity of ZnO substrate play important roles on the growth of single-crystal AlN films by ALD. Finally, non-polar AlN films with single-crystalline structure have been successfully grown on m-plane ZnO (10−10) single-crystal substrates. The as-grown hollow AlN nanotubes arrays and non-polar AlN films with single-crystalline structures are suggested to be highly promising for applications in nanoscale devices. Our research has developed a potential method to obtain other inorganic nanostructures and films with single-crystalline structure at fairly low temperature.

Evaluation of performance constraints and structural optimization of a core-shell ZnO nanorod based eco-friendly perovskite solar cell

In this article, we have studied an identical section of a core-shell ZnO Nanorod (NR) based lead-free perovskite solar cell. Various factors affecting the solar cell’s performance have been rigorously investigated for device optimization; specifically, the length and diameter of the ZnO NR core, perovskite shell thickness, thickness of perovskite cap layer, and hole transport layer (HTL) thickness. The defect density of states (DOS) in the perovskite absorber layer and the effect of interface defect density on the performance of the cell are also studied. We obtained power conversion efficiency (PCE) of 14.50%, the open-circuit voltage (VOC) of 0.96 V; short-circuit current density (JSC) of 18.11 mA/cm2 and Fill factor (FF) of 83.35%. We also analyzed the effect of tilt or inclination of NR on the performance of the cell which is a crucial factor toward achieving high performance. By optimizing the device parameters, we have achieved a PCE of 21.27%, VOC of 0.97 V, JSC of 29.56 mA/cm2, and FF of 84.15% at an inclination of 10-degree tilt with respect to the incident light under AM 1.5 illumination. The shadowing mechanism behind efficiency droop is also presented to further realize an optimal design high-performance PSC.