Explore the vast range of titles available.

Nickel–cobalt hydroxide thin films were synthesized using the chemical bath deposition method, and the effect of thermal annealing (373–673 K) on their physicochemical and electrochemical characteristics was explored. The X-ray diffraction study showed a cubic crystalline structure of NiCo 2 O 4 electrode formed above annealing temperature of 573 K. Field emission scanning electron spectroscopy (FE-SEM) study revealed that after annealing, NiCo 2 O 4 electrode showed urchin-like microspheres morphology with superhydrophilic nature. The electrode annealed at 573 K exhibited outstanding electrochemical performance with a specific capacitance of 470 F g −1 at 0.4 A g −1 current density. Over 2000 cycles, electrode demonstrated capacitive retention of 75.55%. Finally, NiCo 2 O 4 and Fe 2 O 3 thin films were used to construct the asymmetric supercapacitor (ASC) device. The ASC device manifested energy density of 40 Wh kg −1 at power density of 1.66 kW kg −1 and 82% retention after 2000 CV cycles. Graphical Abstract

During last three decades, successive ionic layer adsorption and reaction (SILAR) method, has emerged as one of the solution methods to deposit a variety of compound materials in thin film form. The SILAR method is inexpensive, simple and convenient for large area deposition. A variety of substrates such as insulators, semiconductors, metals and temperature sensitive substrates (like polyester) can be used since the deposition is carried out at or near to room temperature. As a low temperature process, it also avoids oxidation and corrosion of the substrate. The prime requisite for obtaining good quality thin film is the optimization of preparative provisos viz. concentration of the precursors, nature of complexing agent, pH of the precursor solutions and adsorption, reaction and rinsing time durations etc. In the present review article, we have described in detail, successive ionic layer adsorption and reaction (SILAR) method of metal chalcogenide thin films. An extensive survey of thin film materials prepared during past years is made to demonstrate the versatility of SILAR method. Their preparative parameters and structural, optical, electrical properties etc are described. Theoretical background necessary for the SILAR method is also discussed.

The SnO2–RuO2 mixed films are prepared by successive ionic layer adsorption and reaction (SILAR) method. The SnO2 films combined with RuO2 are prepared by varying the deposition cycles of SILAR. The effect of combining SnO2 with RuO2 on structural, morphological and electrochemical properties is studied. It is observed that the crystalline nature of SnO2 changed to amorphous with increase in RuO2 deposition cycles. The morphology is also changed from fibrous-porous to compact after increasing RuO2 deposition cycles. The specific capacitance of SnO2 is increased from 4 to 185 F/g after combined with RuO2. The maximum utilization of RuO2 is observed with specific capacitance of 1010 F/g.

Nickel-cobalt hydroxide thin films were synthesized using the chemical bath deposition method, and the effect of thermal annealing (373-673 K) on their physicochemical and electrochemical characteristics was explored. The X-ray diffraction study showed a cubic crystalline structure of NiCo.sub.2O.sub.4 electrode formed above annealing temperature of 573 K. Field emission scanning electron spectroscopy (FE-SEM) study revealed that after annealing, NiCo.sub.2O.sub.4 electrode showed urchin-like microspheres morphology with superhydrophilic nature. The electrode annealed at 573 K exhibited outstanding electrochemical performance with a specific capacitance of 470 F g.sup.-1 at 0.4 A g.sup.-1 current density. Over 2000 cycles, electrode demonstrated capacitive retention of 75.55%. Finally, NiCo.sub.2O.sub.4 and Fe.sub.2O.sub.3 thin films were used to construct the asymmetric supercapacitor (ASC) device. The ASC device manifested energy density of 40 Wh kg.sup.-1 at power density of 1.66 kW kg.sup.-1 and 82% retention after 2000 CV cycles.

The amorphous hydrous ruthenium oxide (RuO 2 · n H 2 O) thin films were deposited by a simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method. These films were characterized for their structural, surface morphological, and compositional study by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDAX) techniques. The wettability test was carried out by measuring the water contact angle. The scanning electron microscopy study showed small RuO 2 particles are grouped together to form porous agglomerates. The FT-IR study confirmed the formation of hydrous ruthenium oxide films. The hydrophilic nature of ruthenium oxide (RuO 2 · n H 2 O) thin films was observed from water contact angle measurement. The presence of Ru and O in the film was confirmed by EDAX analysis. The supercapacitor behavior of these films studied in 0.5 M H 2 SO 4 electrolyte showed maximum specific capacitance of 162 F g −1 at 10 mV s −1 scan rate. These films exhibit 80% cycling performance after 2,000 cycles. The charge–discharge studies carried at 1 mA cm −2 current density revealed the specific power of 3.5 KW kg −1 and specific energy of 29.7 W Kg −1 with 93% coulombic efficiency.

The utilization of solar energy is an essential aspect in order to sustain in the energy crisis situation. Semiconductor based photoelectrochemical (PEC) cells are used for it. Herein, a binder free approach was employed for the synthesis of CdSe thin films on stainless steel substrate and effect of post annealing (350–500 K) on physicochemical as well as photoelectrochemical properties were investigated. The characterization showed that CdSe thin films crystallized in cubic crystal structure with spherical granular morphology with optical band gap of 1.76 eV. The effect of post annealing on CdSe thin films is further tested by examining their PEC properties. Thin film CdSe electrode annealed at temperature 400 K showed highest fill factor ( FF ) and efficiency ( η ) of 0.32 and 1.54%, respectively. In addition, electrochemical impedance spectroscopy (EIS) study showed superior charge transfer properties.

In the present investigation, we report chemical synthesis of hydrous tin oxide (SnO2:H2O) thin films by successive ionic layer adsorption and reaction (SILAR) method at room temperature (300 K). The films are characterized for their structural and surface morphological properties. The formation of nanocrystalline SnO2 with porous and agglomerated particle morphology is revealed from X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies, respectively. The Fourier transform infrared spectroscopy (FTIR) study confirmed the formation of Sn–O phase and hydrous nature of the deposited film. Static water contact angle studies showed the hydrophilic nature of SnO2:H2O thin film. Electrical resistivity showed the semiconducting behaviour with room temperature electrical resistivity of 105 cm. The electrochemical properties studied in 0·5 M Na2SO4 electrolyte showed a specific capacitance of 25 F g − 1 at 5 mVs − 1 scan rate.

The spinel ferrites are versatile group of metal oxides with good photoelectrochemical and unique magnetic properties, as well as low cost, biocompatible and huge abundance. The magnetic as well as photoelectrochemical properties have been extensively examined. Herein, we have synthesized zinc ferrite (ZnFe 2 O 4 ) thin films on nickel foam via spray pyrolysis method at substrate temperatures of 300, 400, and 500 °C. The physicochemical properties of ZnFe 2 O 4 films were investigated using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and fourier transform infrared spectroscopy (FT-IR) spectroscopy. Electrochemical properties oxygen evolution reaction and supercapacitive performance of ZnFe 2 O 4 thin films were investigated through linear sweep voltammetry, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The ZnFe 2 O 4 thin film synthesized at 400 °C exhibited an overpotential of 319 mV at a current density of 50 mA/cm 2 with a Tafel slope of 115 mV/dec. Furthermore, it also showed a specific capacitance of 335 F/g at 1 mA/cm 2 current density in 1 M KOH electrolyte.

Well-packed pristine CdSe and Indium-doped CdSe (In:CdSe) thin films have been successfully synthesized on a cost-effective stainless steel substrates by simple chemical route and their performance as photoanode in photoelectrochemical (PEC) solar cell was investigated. With the view to enhance the efficiency of solar cell, various preparative parameters were optimized using renowned PEC way. The Pristine CdSe and In:CdSe thin films were characterized for structural, morphological, optical, and photoelectrochemical studies. The structural analysis revealed modest improvement in crystallinity owed to Indium doping. Morphological modulation noticed from cauliflower structure to elliptical-shaped elongated grains, subsequent to insertion of Indium in CdSe lattice. Doped CdSe photoanodes were found to be more hydrophilic in nature than pristine. Both films possess direct transitions with decrease in band gap energies from 2.1 to 1.91 eV, attributable to doping. Improved power conversion efficiency from 0.54 to 0.79% is recorded as an outcome of indium doping.

An effective route towards improving the electrocatalytic performance of materials is the synthesis of nanocrystalline, porous, and layer-structured materials. Herein, porous nickel tungstate (NiWO 4 ) film electrode was prepared on stainless steel (SS) substrate by inexpensive successive ionic layer adsorption and reaction (SILAR) method. This method provides a binder-free, porous, and nanocrystalline thin layer on a SS substrate. The electrocatalytic performance of the nanocrystalline NiWO 4 electrocatalyst was evaluated for enzymeless glucose measurement and water-splitting application. This electrocatalyst exhibited excellent sensitivity of 9731 μA mM −1  cm −2 within the linear range of 25–325 μM. Further, the glucose concentrations present in human blood samples were measured using the proposed nanocrystalline NiWO 4 electrocatalyst. Also, hydrogen evolution reaction, the electrocatalyst exhibited 171 mV of overpotential at 10 mA cm −2 with a Tafel slope of 70 mV dec −1 . Further, chronopotentiometry study was carried out at 100 mA cm −2 and it showed 94% retention after 24 h. These findings greatly promote the outstanding electrocatalytic performance of nanocrystalline and porous NiWO 4 electrocatalysts that outline their applicability for electrochemical catalysis purposes.