Microwave-assisted Chemical Bath Deposition Method Research Articles

Study of optical properties of ZnS and MnZnS (ZnS/MnS) nanostructure thin films; Prepared by microwave-assisted chemical bath deposition method

The main objective of this work is the preparation of ZnS and MnZnS (ZnS/MnS) nanostructure thin films in an ammonia-free solution by microwave-assisted chemical bath deposition (MA-CBD) method and decreasing consume of energy via decreasing deposition time from several hours to several minutes compared to conventional CBD method. ZnS and MnZnS films were deposited on commercial microscope slide glass substrates using acetic acid as a safe complexing agent. Growth rate of the film thickness was obtained approximately 1.8–2.0 nm/min. The influence of [S2−/Zn2+] molar ratio on the formation, quality, and optical properties of the films was investigated. X-ray diffraction results approved the formation of MnS/ZnS hybrid films with a cubic structure for the ZnS and MnS. Atomic force microscopy (AFM) measured the average of roughness around 6.4 nm. Field emission scanning electron microscopy (FE-SEM) exhibited that the layers were dense, homogenous, and free of pinhole or crack with very small particles at about 10–40 nm. Energy-dispersive X-ray spectrometer (EDX) revealed the presence of the Mn in the ZnS thin film and confirmed the deficiency of sulfide in the films. Fluorescence (FL) emission spectra of the films showed a strong dependence on composition as well as population (density) of defect states such as S vacancies. UV–vis results indicated that all films are highly transparent, and their band gap energy varies from 3.6eV to 3.85eV.

Lead sulfide films synthesized by microwave-assisted chemical bath deposition method as efficient counter electrodes for CdS/CdSe sensitized ZnO nanorod solar cells

In this study, PbS thin films are deposited on FTO substrate via a rapid and facile microwave-assisted chemical bath deposition (MACBD) and then used directly as the counter electrodes (CEs) for CdS/CdSe quantum dots co-sensitized ZnO nanorods array solar cells (QDSSC). The resultant PbS CEs show good uniformity, strong adhesion to the FTO and superior electrocatalytic activity for the reduction of polysulfide electrolyte compared to the PbS CEs prepared with conventional CBD method. The combination of ZnO/CdS/CdSe photoanode with the optimum PbS CE shows appreciated power conversion efficiency (PCE) of 4.85%. The augmented photovoltaic performance can be attributed to its high electrocatalytic activity for polysulfide reduction in QDSSC, which results in a low charge transfer resistance at the interface of CE/electrolyte. The results demonstrate the potential application of this MACBD method in fabricating efficient metal sulfide counter electrode for QDSSC.

Synthesis and characterization of polypyrrole thin film by MW-CBD method for NH3 gas sensor

The microwave-assisted chemical bath deposition method is used for synthesis of polypyrrole (Ppy) thin film. The structural, morphological, optical absorption and wettability properties of deposited Ppy thin films are studied using various characterization techniques. The X-ray diffraction pattern shows amorphous nature of Ppy thin film. To confirm the formation of Ppy compound, Fourier transform infrared spectroscopic study is used. The scanning electron microscopy study shows porous structure of Ppy thin film. The optical study revealed that Ppy thin film exhibits band gap of 3.5 eV. The Ppy film exhibited hydrophilic nature with contact angle of 41°. The Ppy films show 85% response to ammonia (NH3) gas at room temperature.

Nanostructured ZnO-based biosensor: DNA immobilization and hybridization

An electrochemical DNA biosensor was successfully fabricated by using (3-aminopropyl) triethoxysilane (APTES) with zinc oxide (ZnO) nanorods synthesized using microwave-assisted chemical bath deposition method on thermally oxidized SiO2 thin films. The structural quality and morphology of the ZnO nanorods were determined by employing scanning electron microscopy (SEM) and X-ray diffraction (XRD), which show a hexagonal wurtzite structure with a preferred orientation along the (101) direction. The surface of the SiO2 thin films was chemically modified with ZnO. Label-free detection DNA immobilization and hybridization were performed using potassium hexacyanoferrate with cyclic voltammetry (CV) measurements. The capacitance, permittivity, and conductivity profiles of the fabricated sensor clearly indicate DNA immobilization and hybridization. Results show that the capacitance values of bare, ZnO- modified surface immobilization, and target DNA hybridization were 46×10−12F, 47×10−8F, 27μF, and 17μF, respectively, at 1Hz. The permittivity measurement increased from 3.94×103 to 251×103 and 165×103 at the frequency range of approximately 200 to 1Hz for bare and DNA immobilization and hybridization, respectively. The measured conductivity values for the bare, ZnO, immobilized, and hybridization device were 2.4×10−9, 10×10−8, 1.6×10−7, and 1.3×10−7Scm−1, respectively.

Study of copper ion adsorption from aqueous solution with different nanostructured and microstructured zinc oxides and zinc hydroxide loaded on activated carbon cloth

Microstructured and nanostructured zinc oxides and zinc hydroxide loaded on activated carbon cloth (ACC) were synthesized by microwave-assisted chemical bath deposition (MACBD) at different pH also and hydrothermal methods.The composition and morphology of samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. Deposited sediments on ACC by hydrothermal are dandelion-like structure with nanoneedles of 50 to 200nm diameter. Deposited samples with MACBD method at pH of 9.8 and 10.8 are flower-like and mixture of flower and rhombic microstructures, respectively. Performance of the synthesized adsorbents (by MACBD and hydrothermal methods) for removal of copper ion was studied by kinetic and equilibrium experiments. The experimental kinetic and equilibrium data have been fitted to different classical and recently developed models. All of the prepared samples behave as super adsorbent for removal of copper ion with maximum adsorption capacity of about 1300mg/g. Finally, the mechanism off adsorption is presented too.

CdS sensitized TiO2 film for photocatalytic reduction of Cr(VI) by microwave-assisted chemical bath deposition method

Abstract CdS quantum dots (QDs) sensitized TiO 2 films were successfully synthesized using one-step microwave assisted chemical bath deposition method, which allows a facile and rapid deposition and integration between CdS QDs and TiO 2 films. The photocatalytic performance of the films fabricated using CdS precursor solutions with different concentrations in the reduction of Cr(VI) under white light emitting diode (LED) light irradiation was investigated. The results show that the CdS sensitization can enhance the photocatalytic performance of TiO 2 film with a maximum reduction rate of 93% for 240 min under white LED light irradiation as compared with the pure TiO 2 film (31%) due to the increase of light absorption and the reduction of recombination of the injected electrons from CdS to TiO 2 .

Fabrication and characterisations of n-CdS/p-PbS heterojunction solar cells using microwave-assisted chemical bath deposition

n-CdS/p-PbS heterojunction solar cells were prepared via microwave-assisted chemical bath deposition method. A cadmium sulfide (CdS) window layer (340nm thickness) was deposited on an indium tin oxide (ITO) glass. A lead sulfide (PbS) absorber layer (985–1380nm thickness) with different molar concentrations (0.02, 0.05, 0.075, and 0.1M) was then grown on ITO/CdS to fabricate a p–n junction. The effects of changing molar concentration of the absorber layer on structural and optical properties of the corresponding PbS thin films and solar cells were investigated. The optical band gap of the films decreased as the molarity increased. The photovoltaic properties (J–V characteristics, short circuit current, open circuit voltage, fill factor, and efficiency) of the CdS/PbS heterostructure cells were examined under 30mW/cm2 solar radiation. Interestingly, changing molar concentration improved the photovoltaic cells performances, the solar cell exhibited its highest efficiency (1.68%) at 0.1M molar concentration.

Microwave assisted chemical bath deposition of vertically aligned ZnO nanorods on a variety of substrates seeded by PVA–Zn(OH)2 nanocomposites

Vertically aligned zinc oxide (ZnO) nanorods were synthesized successfully on p-type GaN, c-lattice Al2O3, ITO glass, and quartz single crystal substrates using the microwave-assisted chemical bath deposition method. All substrates were seeded with a PVA–Zn(OH)2 nanocomposites layer prior to nanorods growth. The effect of substrate type on the vertically alignment and morphology of the zinc oxide nanorods was studied. The diameter of the grown ZnO nanorods ranged from 30 to 170nm. Their structural quality and morphology were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which revealed hexagonal wurtzite structures perpendicular to the substrate along the z-axis in the direction of (002) plane. Photoluminescence (PL) measurements of the grown ZnO nanorods on all substrates exhibited high UV peak intensity compared to broad visible peak. Raman scattering studies were conducted to estimate the lattice vibration modes.

Structural and optical properties of nanocrystalline CdS thin films prepared using microwave-assisted chemical bath deposition

Cadmium sulfide (CdS) nanocrystalline thin films were prepared using the microwave-assisted chemical bath deposition method onto glass substrates at 80°C. Aqueous solutions of either cadmium chloride or cadmium acetate and thiourea were used as sources of Cd2+ and S2− ions, respectively. Two sets of samples with different concentrations were prepared. A microwave oven was used as a heating source to synthesize the nanocrystalline CdS thin films. The prepared thin films had a good adhesion with no pinholes. These films were examined for their structural and surface morphologies by X-ray diffraction (XRD), scanning electron microscopy, and atomic force microscopy. The optical properties were investigated using UV–vis spectrophotometer, photoluminescence, and Raman spectroscopy. Particle size values obtained from XRD were compared with these calculated using effective mass models. The values of optical band gaps according to optical transmission measurements decreased as the ion source molar concentration increased.

CdS/CdSe-Cosensitized TiO2 Photoanode for Quantum-Dot-Sensitized Solar Cells by a Microwave-Assisted Chemical Bath Deposition Method

A CdS/CdSe quantum-dot (QD)-cosensitized TiO(2) film has been fabricated using a microwave-assisted chemical bath deposition technique and used as a photoanode for QD-sensitized solar cells. The technique allows a direct and rapid deposition of QDs and forms a good contact between QDs and TiO(2) films. The photovoltaic performance of the as-prepared cell is investigated. The results show that the performance of the CdS/CdSe-cosensitized cell achieves a short-circuit current density of 16.1 mA cm(-2) and a power conversion efficiency of 3.06% at one sun (AM 1.5 G, 100 mW cm(-2)), which is comparable to the one fabricated using conventional successive ionic layer adsorption and reaction technique.

Growth of Shape‐ and Size‐Selective Zinc Oxide Nanorods by a Microwave‐Assisted Chemical Bath Deposition Method: Effect on Photocatalysis Properties

Herein, we demonstrate the shape- and size-selective growth of ZnO nanostructures on indium tin oxide-coated glass substrates by using a microwave-assisted chemical bath deposition method. By systematically controlling the deposition parameters, it is possible to produce shape- and size-selective nanostructures with high alignment and uniformity. Specifically, the pH of the bath can be used to control the shape of rods from bundled structures to tapered and flat tips. Furthermore, the deposition temperature can be used to control the size of the ZnO array from 770 to 125 nm. The prepared rods were active catalysts in the degradation of methylene blue under UV radiation, and exhibited size-dependent activity.