Simple Successive Ionic Layer Adsorption And Reaction Research Articles

Transformation of cadmium hydroxide to cadmium oxide thin films synthesized by SILAR deposition process: Role of varying deposition cycles

Successive Ionic Layer Adsorption and Reaction (SILAR) was used to deposit nanocrystalline cadmium oxide (CdO) thin films on microscopic glass substrates for various cycles (40–120). This is based on alternate dipping of the substrate in CdCl2 solution made alkaline (pH ∼12) with NaOH, rinsing with distilled water, followed by air treatment with air dryer and annealing at 300°C for 1h in air. The prepared films were characterized by X-ray diffraction (XRD), UV–Visible Spectrophotomer (UV–Vis) and Scanning Electron Microscopy (SEM). The 80th cycle was observed to be the saturation stage for this reaction. The XRD results confirmed the films to be CdO with some Cd(OH)2 phase at higher deposition cycles. The films were polycrystalline in nature having high orientation along (111) and (200) planes. As the number of cycles increases the calculated average crystallite sizes increase gradually up till the 80th cycle after which a gradual decrease in the crystallite size was observed with increasing number of cycles. The films’ transmittance in the visible and near infrared region decreased as the number of cycles increased and ranged between 25 and 80%. This work shows the feasibility of using simple SILAR method at room temperature to obtain Cd(OH)2 films which are transformed to CdO thin films after annealing.

Fabrication of In2S3 nanoparticle decorated TiO2 nanotube arrays by successive ionic layer adsorption and reaction technique and their photocatalytic application.

In2S3 nanoparticle (NP) decorated self-organized TiO2 nanotube array (In2S3/TiO2 NT) hybrids were fabricated via simple successive ionic layer adsorption and reaction (SILAR) technique. The In2S3 NPs in a size of about 15 nm were found to deposit on the top surface of the highly oriented TiO2 NT while without clogging the tube entrances. The loading amount of In2S3 NPs on the TiO2 NT was controlled by the cycle number of SILAR deposition. Compared with the bare TiO2 NT, the In2S3/TiO2 NT hybrids showed stronger absorption in the visible light region and significantly enhanced photocurrent density. The photocatalytic activity of the In2S3/TiO2 NT photocatalyst far exceeds that of bare TiO2 NT in the degradation of typical herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) under simulated solar light. After 160-min irradiation, almost 100% 2,4-D removal is obtained on the 7-In2S3/TiO2 NT prepared through seven SILAR deposition cycles, much higher than 26% on the bare TiO2 NT. After 10 successive cycles of photocatalytic process with total 1,600 min of irradiation, In2S3/TiO2 NT maintained as high 2,4-D removal efficiency as 95.1% with good stability and easy recovery, which justifies the potential of the photocatalytic system in application for the photocatalytic removal of organic pollutants such as herbicides or pesticides from water.

Simple synthesis method of Bi2S3/CdS quantum dots cosensitized TiO2 nanotubes array with enhanced photoelectrochemical and photocatalytic activity

A TiO2 nanotubes array film with nanowires directly formed on top (denoted as TiO2 NTWs) was prepared by an anodization method (potentiostatic anodization growth). Bi2S3 QDs were sensitized on the CdS/TiO2 NTWs array by a simple successive ionic layer adsorption and reaction (S-SILAR). A short-circuit photocurrent density of 2.16 mA cm−2 was obtained under an illumination of AM 1.5 G. The data of the photoelectrochemical performance test show that Bi2S3/CdS co-modification can boost the photocurrent density of the bare TiO2 NTWs by up to 308%. The photocatalytic activity was tested by treating rhodamine B (RhB) and methyl orange (MO) solutions, which were degraded completely after 240 min and 210 min, respectively. The present study shows the Bi2S3/CdS/TiO2 NTWs array can be applied in photocatalytic devices, and the greatest advantages are low-cost, easy reuse and recyclability.

Synthesis of polythiophene thin films by simple successive ionic layer adsorption and reaction (SILAR) method for supercapacitor application

In the present work, polythiophene thin films have been prepared by simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method at room temperature. The oxidative polymerization of thiophene monomer is carried out using FeCl3 as an oxidizing agent. The two beaker SILAR system was adopted with thiophene in acetonitrile solution as a cationic precursor and FeCl3 solution in double distilled water as an anionic precursor for polymerization of thiophene. The physico-chemical properties of polythiophene films are studied for the analysis of structural, morphological, optical and electrical properties. The XRD showed the formation of amorphous polythiophene, whereas electrical and optical studies showed p-type electrical conductivity and band gap 2.90eV, respectively for polythiophene film. The electrochemical performance of polythiophene electrode was evaluated using cyclic voltammetry (CV) and galvanostatic charge–discharge measurements. A specific capacitance of 252Fg−1 was obtained in 0.1M LiClO4 solution.

Electrospun TiO2 nanostructures sensitized by CdS in conjunction with CoS counter electrodes: Quantum dot-sensitized solar cells all prepared by successive ionic layer adsorption and reaction

Development of low-cost quantum dot-sensitized solar cells (QDSCs) with intermediate efficiency is of great interests among global researchers. In this communication, we report a CdS QDSC featuring CoS counter electrode that is all prepared by successive ionic layer adsorption and reaction (SILAR) method. Promising photovoltaic performance of an overall power conversion efficiency of nearly 1% is obtained in the presence of a methanol-free polysulfide electrolyte under standard 1-Sun illumination of 100mWcm−2. Based on the cost-effective nature of electrospinning technique and the simple SILAR preparation of both the photoelectrode and the counter electrode without any elaborate procedures, we believe such a methodology would open up new vistas for wide deployment of solar cells due to great reduction of the fabrication cost.

Synthesis of photosensitive nanograined TiO 2 thin films by SILAR method

Nanocrystalline TiO 2 thin films are deposited by simple successive ionic layer adsorption and reaction (SILAR) method on glass and fluorine-doped tin oxide (FTO)-coated glass substrate from aqueous solution. The as-deposited films are heat treated at 673 K for 2 h in air. The change in structural, morphological and optical properties are studied by means of X-ray diffraction (XRD), selected area electron diffraction (SAED), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), transmission electron microscopy (TEM) and UV–vis–NIR spectrophotometer. The results show that the SILAR method allows the formation of anatase, nanocrystalline, and porous TiO 2 thin films. The heat-treated film showed conversion efficiency of 0.047% in photoelectrochemical cell with 1 M NaOH electrolyte.

Studies on structural, optical and electrical properties of indium sulfide thin films

Onto amorphous glass substrates, indium sulfide (In2S3) thin films have been successfully deposited using versatile and simple successive ionic layer adsorption and reaction (SILAR) method. These films are characterized by structural, optical and electrical measurement techniques. Uniform distribution of grains is clearly noted from the photograph of scanning electron microscope (SEM). Cubic structure with amorphous nature of films is reported. The optical band gap of In2S3 thin films is estimated to be 2.3eV. Films were highly resistive possesses resistivity of the order of 105Ωcm.

Photoelectrochemical characterization of chemically deposited (CdS)X(Bi2S3)1−X composite thin films

(CdS) X (Bi 2 S 3 ) 1− X composite thin films were chemically deposited using simple successive ionic layer adsorption and reaction (SILAR) method onto glass and fluorine doped tin oxide (FTO) coated glass substrates. The films were annealed in air at 200°C for 2 h and used to fabricate photoelectrochemical cells of configuration: (CdS) X (Bi 2 S 3 ) 1− X /Na 2 SSNaOH/C and their properties, such as current–voltage ( I – V ), photovoltaic output, spectral response, capacitance–vo1tage (Mott–Schotttty plots), etc. It is found that the (CdS) X (Bi 2 S 3 ) 1− X composite thin films are photoactive. The effect of composition ‘ X ’ on these properties was studied.