Simple Successive Ionic Layer Adsorption And Reaction Research Articles

One-step synthesis of magnetically recoverable AgCl/Fe3O4@MIL-100(Fe) for high-performance photocatalysis

We present a novel method to facilely prepare magnetically recoverable AgCl/Fe3O4 @MIL-100(Fe) (ACFM) nanostructures for photocatalytic degradation of rhodamine B (RhB). The ACFM was directly prepared via a simple successive ionic layer adsorption and reaction (SILAR) deposition of MIL-100(Fe) on solvothermal synthesized Ag/Fe3O4 nanoparticles, in which process Ag was completely oxidized into AgCl concurrent with the formation of MIL-100(Fe). The ACFM prepared with 15 SILAR cycles exhibits 92.9% efficiency towards photodegrading RhB within 30 min under visible light illumination, which is higher than that of the individual structure of AgCl/Fe3O4, Ag/Fe3O4 @MIL-100(Fe) or Fe3O4 @MIL-100(Fe). The remarkably enhanced photocatalytic performance is attributed to the abundant active sites and sufficient visible light response of MIL-100(Fe), as well as effective charge separation at the heterojunction interface between AgCl and MIL-100(Fe). Furthermore, the obtained ACFM can be quickly separated from the pollutant solution with a magnet and possesses good stability for recycling photocatalysis. In light of the study, the ACFM nanostructures are believed to be applied as promising photocatalysts for practical applications.

Peony flower-like CuxS@NiMn LDH heterostructure as an efficient electrocatalyst for the oxygen evolution reaction

Hydrogen production from electrochemical water splitting has attracted more and more attention, and the development of efficient oxygen evolution reaction (OER) electrocatalyst is of great importance to this technology. In this work, peony flower-like CuxS@NiMn LDH was in situ deposited on nickel foam by simple successive ionic layer adsorption and reaction (SILAR) and hydrothermal method. The results show that CuxS exists in a mixed phase of CuS and Cu2S with porous structure, NiMn LDH grows vertically on CuxS particle surface, and a heterostructure between CuxS and NiMn LDH is formed. The CuxS@NiMn LDH/NF electrode exhibits superior OER activity with an overpotential of 263 mV at a current density of 10 mA cm−2, lower Tafel slope of only 57.79 mV dec−1, and higher stability during a 60-h test. This excellent performance is attributed to the porous structure and synergistic effect between NiMn LDH and CuxS, which can promote mass diffusion, decrease the charge transfer resistance and accelerate the electron transport during the electrocatalytic process.

Syntheses, structural evolution, electrical and optoelectronic characterization of ZnO/CuO composite films doped with transition metal Mn2+ ions

This study was done aiming to evaluate the influence of manganese (Mn) as a transition metal on the morphological, structural, optical, electrical, and optoelectronic characteristics of nanostructured ZnO/CuO films. Different Mn concentrations (1 and 2 M%) were used to analyze these properties. In the present research, we have described the synthesis of nanocomposite pristine ZnO/CuO and Mn-doped ZnO/CuO (Mn: ZnO/CuO) oxide films by using simple successive ionic layer adsorption and reaction (SILAR) procedure. Scanning electron microscopy (SEM) and atomic force microscope (AFM) pictures reveal that the surface structure of ZnO/CuO nanocomposites was effectively altered by Mn2+ ion substitution. Energy-dispersive X-ray analysis (EDX) confirms the presence of Zn, Cu, O, and Mn elements in the synthesized nanofilms. The film thickness had decreased from 1.65 to 1.23 μm as a function of increasing Mn2+ concentration. The X-ray diffraction (XRD) pattern revealed that the synthesized ZnO/CuO nanocomposite was polycrystalline and the crystallite size decreases from 40.16 to 34.14 nm with increasing Mn2+ ion concentrations. The optical bandgap energy was found using Tauc's graph and it varied from 2.37 to 2.56 eV. A maximum average transmittance (30%) was obtained for 2 M% Mn2+ concentration. Electrical measurement of the ZnO/CuO composite films shows sheet resistance (Rs) change between 1.01 and 0.41 (x108Ω/sq.) depending on temperature from 300 K to 400 K. The biggest figure of merit observed in this work was 4.69 × 10−8 Ω−1. The results have shown that Mn-doping has an important effect on the physical attributes of SILAR-deposited ZnO/CuO films.

SILAR synthesized dysprosium selenide (Dy2Se3) thin films for hybrid electrochemical capacitors

As the necessity of energy storage is continuously increasing, new materials have been investigated for electrochemical energy storage, especially for electrochemical capacitors. These storage devices are rapidly convertible as well as air pollution free. Therefore, a number of materials have been explored as electrode materials for supercapacitors to fulfill different requirements of electrochemical energy storage. Herewith, dysprosium selenide (Dy2Se3) films were prepared using the simple successive ionic layer adsorption and reaction (SILAR) method and characterized using different physico-chemical techniques. The specific capacitance (Cs) of 92 F g−1 was obtained at the current density of 2.85 A g−1 in 1 M LiClO4 electrolyte with a retention of 85% over 5000 galvanostatic charge-discharge (GCD) cycles performed at a current density of 4 A g−1. The flexible solid-state hybrid electrochemical capacitor of configuration Dy2Se3/LiClO4-PVA/MnO2 showed Cs of 83 F g−1 and specific energy of 18 Wh kg−1 at a specific power of 2.7 kW kg−1. This hybrid device retained 92% of capacitance at a device bending angle of 160°. These results demonstrate the facile synthesis of Dy2Se3 and its possible use in electrochemical energy storage applications.

Enhanced Photoresponse and Wavelength Selectivity by SILAR-Coated Quantum Dots on Two-Dimensional WSe2 Crystals.

High-performance photodetectors play crucial roles as an essential tool in many fields of science and technology, such as photonics, imaging, spectroscopy, and data communications. Demands for desired efficiency and low-cost new photodetectors through facile manufacturing methods have become a long-standing challenge. We used a simple successive ionic layer adsorption and reaction (SILAR) method to synthesize CdS, CdSe, and PbS nanoparticles directly grown on WSe2 crystalline flakes. In addition to the excellent wavelength selectivity for (30 nm) CdS, (30 nm) CdSe, and (6 nm) PbS/WSe2 heterostructures, the hybrid devices presented an efficient photodetector with a photoresponsivity of 48.72 A/W, a quantum efficiency of 71%, and a response time of 2.5–3.5 ms. Considering the energy band bending structure and numerical simulation data, the electric field distribution at interfaces and photocarrier generation/recombination rates have been studied. The introduced fabrication strategy is fully compatible with the semiconductor industry process, and it can be used as a novel method for fabricating wavelength-tunable and high-performance photodetectors toward innovative optoelectronic applications.

Effect of ascorbic acid on the properties of tin sulfide films for supercapacitor application

A novel synthesis of tin sulfide film was used for the first time when the film was prepared directly from abundant and biodegradable precursors via a simple SILAR (successive ionic layer adsorption and reaction) method at 40 °C. The structural, optical and electrochemical properties of tin sulfides are explored by changing the number (20 or 30) of SILAR cycles and the quantity of L-ascorbic acid (0.6-1.3 g). X-ray diffraction data showed the multiphase composition consisting of SnS and Sn2S3 in obtained films on fluorine doped tin oxide coated glass slides and Raman spectroscopy confirmed this. The most intensive peaks are assigned to mineral herzenbergite. Scanning electron microscopy showed that the films consist of densely packed irregular clusters of nanoparticles. The crystallite size was in the range of 9 - 15 nm and was dependent on the number of SILAR deposition cycles. The average size of the thickness of films varied from 310 to 1050 nm. The bandgap values calculated using ultraviolet-visible light spectroscopy data are very close to the theoretical values of herzenbergite (0.9- 1.3 eV). Electrochemical measurements showed that among all the films tested in this study, a tin sulfide film prepared with the lowest quantity of ascorbic acid is able to generate the highest specific capacitance of 6.35 F⋅g−1 with the best specific energy value of 3.53 Wh⋅kg−1. These results confirmed that the samples are promising candidates to be used as supercapacitors.

Novel TiO2/Bi4Ti3O12 nanorod arrays decorated with Co-Pi for boosted solar photoelectrochemical water splitting

We present a simple methodology to construct novel Co-Pi decorated TiO 2 /Bi 4 Ti 3 O 12 nanorod (TiO 2 /BTO@Co-Pi NR) arrays as photoanode for enhanced water splitting. By using successive ionic layer adsorption and reaction (SILAR) method, controllable amounts of BiOI nanoplates were uniformly immobilized on the hydrothermal grown TiO 2 NR arrays on Fluorine-doped tin oxide (FTO) substrate. TiO 2 /BTO NR heterojunction was conveniently obtained by partial conversion of TiO 2 to high crystallized Bi 4 Ti 3 O 12 through a solid-state reaction with BiOI nanoplates at high temperature. Afterwards, Co-Pi nanoparticles were deposited on TiO 2 /BTO by photoelectrical deposition to generate TiO 2 /BTO@Co-Pi composites. Photoelectrochemical (PEC) measurements have demonstrated that the prepared TiO 2 /BTO photoanode exhibits extremely enhanced performance than pristine TiO 2 for PEC water splitting thanks to the increased visible light absorption and photogenerated charge separation efficiency. Moreover, both the photocurrent density and incident photo-to-current conversion efficiency (IPCE) were further improved after the decoration of Co-Pi. This work provides a feasible and low-cost strategy to establish TiO 2 /Bi 4 Ti 3 O 12 based photoelectrode, therefore, is suitable for practical applications. • Novel TiO 2 /Bi 4 Ti 3 O 12 nanorod arrays were easily constructed by simple SILAR and solid-state reaction. • Controllable Bi 4 Ti 3 O 12 could be formed by adjusting the SILAR cycles to achieve a optimium photocurrent. • BTO can largely enhance the IPCE and photocurrent density, which were further improved by Co-Pi nanoparticles.

Facile synthesis of nickel cobalt sulfide nano flowers for high performance supercapacitor applications

A facile synthesis of nickel cobalt sulfide (NCS) nanoflowers have been deposited successfully onto binder free 3D nickel foam electrodes using simple successive ionic layer adsorption and reaction (SILAR) method for supercapacitor applications. The obtained NCS nanoflowers manifest ultrahigh specific capacitance of 1899 F g−1 at a scan rate of 5 mV s−1. The NCS nanoflowers exhibit a prominent energy density of 55.16 Wh kg−1 at power density of 495 W kg−1 and superior cyclic stability of 94% after 10000 cycles. In addition, the asymmetric supercapacitor (ASC) device is fabricated using NCS nanoflower as positive and reduced graphene oxide (rGO) as negative electrodes, respectively. The ASC (NCS//rGO) delivered good capacity with excellent energy and power densities within 1.6 V wider potential window. Hence, NCS nanoflowers are an outstanding material for energy storage applications in near future.

Facile SILAR Processed Bi2S3:PbS Solid Solution on MWCNTs for High‐performance Electrochemical Supercapacitor

Summary of main observation and conclusionCarbon based composite materials have gained much attention because of fulfilling desirable properties for supercapacitor application. In the featured work, the thin film of Bi2S3:PbS solid solution has been synthesized on multi‐walled carbon nanotubes (MWCNTs) by simple successive ionic layer adsorption and reaction (SILAR) method. The nanoparticle morphology provides sufficient electroactive channels for electrolyte ions to penetrate during electrochemical activities. The composite exhibits superior specific capacitance 676 F/g at constant specific current density of 5.56 A/g with fast charge‐discharge cycles. In association of energy storage characteristics, the fabricated symmetric cell exhibits excellent energy density of 13.36 Wh/kg by acquiring power density of 0.83 kW/kg. The superior results of the hybrid electrode promise a novel direction for high performance supercapacitor application.

Fabrication of Durable Ordered Ta2O5 Nanotube Arrays Decorated with Bi2S3 Quantum Dots.

One of the most important challenges in the fabrication of ordered tantalum pentaoxide (Ta2O5) nanotube arrays (NTs) via the electrochemical method is the formation of nanotubes that adhere well to the Ta substrate. In this paper, we propose a new protocol that allows tight-fitting Ta2O5 nanotubes to be obtained through the anodic oxidation of tantalum foil. Moreover, to enhance their activity in the photocatalytic reaction, in this study, they have been decorated by nontoxic bismuth sulfide (Bi2S3) quantum dots (QDs) via a simple successive ionic layer adsorption and reaction (SILAR) method. Transmission electron microscopy (TEM) analysis revealed that quantum dots with a size in the range of 6–11 nm were located both inside and on the external surfaces of the Ta2O5 NTs. The effect of the anodization time and annealing conditions, as well as the effect of cycle numbers in the SILAR method, on the surface properties and photoactivity of Ta2O5 nanotubes and Bi2S3/Ta2O5 composites have been investigated. The Ta2O5 nanotubes decorated with Bi2S3 QDs exhibit high photocatalytic activity in the toluene degradation reaction, i.e., 99% of toluene (C0 = 200 ppm) was degraded after 5 min of UV-Vis irradiation. Therefore, the proposed anodic oxidation of tantalum (Ta) foil followed by SILAR decorating allows a photocatalytic surface, ready to use for pollutant degradation in the gas phase, to be obtained.

Visible-light-driven, hierarchically heterostructured, and flexible silver/bismuth oxyiodide/titania nanofibrous membranes for highly efficient water disinfection

Constructing a flexible inorganic membrane photocatalyst for efficient visible-light-driven water disinfection is highly desired but remains a great challenge. Herein, we fabricated a flexible and heterostructured silver/bismuth oxyiodide/titania (Ag/BiOI/TiO2) nanofibrous membrane by combining the electrospinning technique with simple successive ionic layer adsorption and reaction (SILAR) and photodeposition process. In this ternary nanocomposite, ultrathin BiOI nanoplates were firmly anchored onto TiO2 nanofibers, while Ag nanoparticles were uniformly decorated on the surface of both BiOI and TiO2. Benefiting from the large surface area, improved visible-light absorption, and the effective interfacial charge transfer induced by multi-heterojunctions, the resultant Ag/BiOI/TiO2 membrane exhibited superior photocatalytic disinfection activity (7.5 log inactivation of E. coli within 1 h) under visible light illumination. Moreover, the plasmonic Z-scheme charge transfer mode was also proposed for Ag/BiOI/TiO2 system according to the band structure and reactive species analysis. More significantly, the Ag/BiOI/TiO2 membrane-based photoreactor could be facilely constructed for high-efficiency disinfection of high volume contaminated water, and the membrane still maintained good structural integrity and mechanical flexibility after utilization. This work may open up new avenues for designing and constructing flexible high-performance photocatalytic membranes for environmental applications.

Facile growth of AgVO3 nanoparticles on Mo-doped BiVO4 film for enhanced photoelectrochemical water oxidation

BiVO4 is largely restricted by its intrinsic poor electron mobility and sluggish surface reaction. Aiming at eliminating the deficiency of BiVO4, we assemble a novel composite photoanode through simultaneous bulk and surface modification. In detail, controllable Mo doping is manipulated through a spin-coating method, and AgVO3 nanoparticles are loaded by successive ionic layer adsorption and reaction (SILAR) process. The as-prepared photoanode boosts the photocurrent density by 7 folds at 1.23 V vs. RHE and moves the onset potential negatively by 387 mV compared to the bare BiVO4. Furthermore, the charge injection efficiency is substantially boosted to 49% at 1.23 VRHE, nearly 5 times as that of pure BiVO4. With detailed physical and electrochemical characterization, we reveal the essential reason for the boosted photoelectrochemical activity. Appropriate Mo doping can simultaneously enhance the carrier density and electron mobility of BiVO4. Specifically, more (0 4 0) facet are exposed for retarding charge recombination and increasing photocatalytic reaction sites. Then the simple SILAR process grows AgVO3 nanoparticles homogeneously with uniform diameter of 3–5 nm on BiVO4, forming p-n heterojunction to accelerate charge separation, and abundant oxygen vacancy emerged on the surface, which has been demonstrated as active sites for water oxidation reaction.

Preparation of Eu-Doped Cu2O Thin Films Using Different Concentrations by SILAR and Their Heterojunction Property with ZnO

Europium-doped Cu2O thin films were prepared by simple successive ionic layer adsorption and reaction (SILAR) with different Eu doping concentrations: 1%, 3% and 5%. The effect of doping level on structural, optical, surface morphological and electrical properties of the films were studied by x-ray diffraction analysis, UV–Vis spectroscopy, scanning electron microscopy and Hall effect measurements, respectively. Crystallite size, dislocation density, microstrain and texture coefficient of the films were estimated using x-ray diffraction data. The crystallite size was found to vary between 27 nm and 21 nm for the change of doping percentage 1–5%. Morphology of Eu:Cu2O and ZnO films had cauliflower and hexagonal shapes, respectively, without any cracks. Optical studies done on the films revealed an increase of band gap as 2.08 eV, 2.26 eV and 2.41 eV for Eu doping concentrations of 1%, 3% and 5%, respectively. The ZnO film showed a maximum of 80% transmittance and band gap of 3.20 eV. Photoluminescence (PL) studies revealed two emission peaks centered at 394 nm and 377 nm for the Eu:Cu2O and ZnO films, respectively. Eu:Cu2O/ZnO heterojunction solar cells were also prepared and their properties studied; they were found to show increased open circuit voltage and short circuit current for 5% Eu doping concentration.

SILAR preparation of Bi2S3 nanoparticles sensitized TiO2 nanotube arrays for efficient solar cells and photocatalysts

Bi2S3 nanoparticles were deposited on TiO2 nanotube arrays (TiO2 NTs/Bi2S3) by the simple successive ionic layer adsorption and reaction (SILAR) method. The morphology, optical absorption and photoelectrochemical properties of TiO2 NTs/Bi2S3 were investigated by the changing of SILAR cycles. The results indicated that the TiO2 NTs/Bi2S3 (5) prepared with 5 SILAR cycles showed the optimal photoelectrochemical properties. The visible light photocurrent density of TiO2 NTs/Bi2S3 (5) was 5.99 mA/cm2, the photovoltage was −0.29 V/cm2, the flat band was −0.67 V, and the carrier concentration was 1.15 × 1020 cm-3. The TiO2 NTs/Bi2S3 (5) showed the optimal photoelectrocatalytic (PEC) removal efficiencies of rhodamine B (RhB), methyl orange (MO) and Cr(VI). Furthermore, the photoelectrochemical mechanism was tentatively proposed, and the excellent solar absorption and electron transportation were the main reason for the high photoelectric conversion and PEC removal of pollutants.

Highly effective photocatalysts based on carbon nanofibers decorated with TiO2 and CdSe under visible light

A highly effective photocatalyst based on CdSe quantum dots (QDs) and TiO2 nanoparticles well-dispersed on carbon nanofibers (CNFs), named as CdSe/TiO2/CNF was synthesized by simple successive ionic layer adsorption and reaction (SILAR) method on TiO2/CNF. It was verified by spectroscopic analysis that CdSe QDs were successfully synthesized and some aggregations and oxide phases existed in CdSe/TiO2/CNF. The photocatalytic activity of CdSe/TiO2/CNF was demonstrated for decomposition of methylene (MB) aqueous solutions. The tests were performed for different MB concentrations and light irradiation. It was found that CdSe/TiO2/CNF showed high photocatalytic activity under visible light irradiation and even high MB concentrations.

Nanostructure CdS/ZnO heterojunction configuration for photocatalytic degradation of Methylene blue

In the present manuscript, thin films of Zinc Oxide (ZnO) have been deposited on a FTO substrate using a simple successive ionic layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) method. Cadmium Sulphide (CdS) nanoparticles are sensitized over ZnO thin films using SILAR method. The synthesized nanostructured CdS/ZnO heterojunction thin films was characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis spectroscopy and Raman spectroscopy techniques. The band gap of CdS nanoparticles over ZnO nanostructure was found to be about 3.20 eV. The photocatalytic activities of the deposited CdS/ZnO thin films were evaluated by the degradation of methylene blue (MB) in an aqueous solution under sun light irradiation.

Structural, optical and nonlinear optical studies of AZO thin film prepared by SILAR method for electro-optic applications

Aluminium doped (i.e. 3at%) zinc oxide (AZO) thin films were prepared by simple successive ionic layer adsorption and reaction (SILAR) method with different dipping cycles. The structural and surface morphology of AZO thin films were studied by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical parameters such as, transmittance, band gap, refractive index, extinction coefficient, dielectric constant and nonlinear optical properties of AZO films were investigated. XRD pattern revealed the formation of hexagonal phase ZnO and the intensity of the film was found to increase with increasing dipping cycle. The crystallite size was found to be in the range of 29–37nm. Scanning Electron Microscope (SEM) images show the presence of small sized grains, revealing that the smoothest surface was obtained at all the films. The EDAX spectrum of AZO conforms the presence of Zn, O and Al. The optical transmittance in the visible region is high 87% and the band gap value is 3.23eV. The optical transmittance is decreased with respect to dipping cycles. The room temperature PL studies revealed that the AZO films prepared at (30 cycles) has good film quality with lesser defect density. The third order nonlinear optical parameters were also studied using Z-scan technique to know the applications of deposited films in nonlinear devices. The third order nonlinear susceptibility value is found to be 1.69 × 10−7, 3.34 × 10−8, 1.33 × 10−7and 2.52 × 10−7 for AZO films deposited after 15, 20, 25 and 30 dipping cycles.

Photoelectrocatalytic removal of organic dyes and Cr(VI) ions using Ag3PO4 nanoparticles sensitized TiO2 nanotube arrays

In this paper, Ag3PO4 nanoparticles were prepared on the surface of TiO2 nanotube arrays (TiO2 NTs/Ag3PO4) by a simple successive ionic layer adsorption and reaction (SILAR) method, and the morphology and optical property were investigated by Scanning electron microscope (SEM) and UV–vis diffusion reflectance spectroscopy (DRS). The deposition of Ag3PO4 nanoparticles could exceedingly extend the absorption of TiO2 nanotubes to the visible light region, which was the prerequisite of TiO2 NTs-Ag3PO4 using in solar cells and photocatalysts. Therefore, TiO2 NTs/Ag3PO4 photoelectrodes significantly improved visible light photocurrent densities compared with pure TiO2 nanotubes. Moreover, TiO2 NTs/Ag3PO4 photocatalysts also achieved high photoelectrocatalytic efficiencies in the removal of organic dyes and Cr(VI) ions. The nontoxic and environmental Ag-based sensitizer would further explore the applications of TiO2 nanotubes into fields of food, drinking water, medicine and so on.

Graphene/CuS/PbS nanocomposite as an effective counter electrode for quantum dot sensitized solar cells

In this paper, we introduce graphene/CuS/PbS nanocomposite as an effective counter electrode (CE) for quantum dot sensitized solar cells (QDSCs). The result indicated that the catalytic performance of CuS/PbS CEs was enhanced by pre deposition of graphene (G) sheets on the fluorine doped tin oxide (FTO) coated glass substrates. Here, various CEs are made by the simple successive ionic layer adsorption and reaction (SILAR) method. The result indicates that the fill factor of the cells with FTO/G/CuS/PbS CEs enhances in compare with the FTO/CuS/PbS CEs. Here, for the CdS/CdSe QD sensitized cells and G/CuS/PbS CEs, the cells' efficiency and fill factor is obtained 3.21% and 0.51 respectively which is enhanced compared to the CuS/PbS CEs with 2.54% efficiency and 0.36 fill factor. The present results indicate that the compact structure of the CuS/PbS CEs, replaces with a porous structure after graphene pre deposition which is expected to enhance the electrolyte/CE interface and consequently the fill factor. According to the obtained results, in spite of the poor catalytic activity of the graphene in the polysulfide electrolyte, it simply modifies the morphology of the CuS/PbS CEs for enhancing their performance. The results also demonstrated that G pre deposition can be systematically applied to enhance the performance of CEs in QDSCs.

Fabrication of the (Y2O3:Yb–Er)/Bi2S3 composite film for near-infrared photoresponse

Y2O3:Yb-Er/Bi2S3 composite films with photoactive current generation under NIR light excitation were fabricated by electro-deposition and a simple successive ionic layer adsorption and reaction (SILAR) method.