Synthesis and Characterization of Cobalt-Doped WS2 Nanorods for Lithium Battery Applications (original) (raw)
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Materials Science in Semiconductor Processing, 2019
In this paper, cobalt sulfide thin film was synthesized on glass and steel substrates via chemical route. The structure, surface morphology, and optical characterization of the deposited thin films indicated a strong relationship between the number of deposition cycles and intrinsic properties. The scanning electron microscope (SEM) showed a uniform morphology with randomly oriented nano-grains of cobalt sulfide film at varying deposition cycles. The XRD spectra revealed that the films became amorphous as the number of deposition cycles increased. The crystalline films had a hexagonal structure of average crystallite size of 27.55 nm. The optical transmission spectra of the films gave a direct band gap energy which varied between 1.90 eV and 2.20 eV with an average value of the optical conductivity was 1.77 10 17 S ̶ 1. The electrochemical energy storage behavior of the electrodes was evaluated using cyclic voltammetery (CV), galvanostatic charge-discharge (GCD) technique and electrochemical impedance spectroscopy (EIS) in a neutral electrolyte of 0.1 M solution of Na 2 SO 4 performed on films deposited on a steel substrate. A specific capacity of 298.4 mAh/g at a scan rate of 20 mV/s was obtained at 30 deposition cycles. The SILAR deposited CoS thin film electrodes is a promising material for both energy storage and optoelectronics application based on the electrochemical properties obtained. The material showed about 80% charge capacity retention after 1000 cycles.
ES Materials & Manufacturing
Photoelectrochemical cell technology is one of the simplest technologies, which converts light energy directly into electricity. The synthesis of cadmium sulfide (CdS) nanocrystals (NCs) was performed by the facile hot injection method. The NCs were characterized by different techniques such as XRD, Raman, UV-Vis, FESEM, and XPS. The XRD and Raman patterns confirm the phase pure hexagonal CdS NCs. The band gap of NCs calculated from the UV-Visible spectrum is at 2.64 eV, indicating good absorption in the visible spectrum. XPS analysis confirmed the presence of individual elements in CdS NCs. The CdS thin-films having different thicknesses were prepared on FTO substrates using the spin coating technique. Photoelectrochemical (PEC) investigation of CdS NCs thin-films photoelectrodes was performed by varying its thickness. The increase in the thickness of thin-films increased photocurrent density.
Optical investigation on zinc doped cadmium sulphide nanocrystalline thin films
Optical investigation on blue shift behavior of zinc doped cadmium sulphide nano-crystalline thin films have been prepared by spray pyrolysis method at 375 ± 10 C. The crystallinity and phase have been characterized by glancing angle X-ray diffraction. The XRD peaks confirm the hexagonal structure of cadmium sulphide. The crystallites sizes are found its range of 15e20 nm. The surface morphology is analyzed by using field emission scanning electron microscopy. The morphology of the film is seen as uniform distribution of homogeneous fine solid grains which are compact in nature. Optical absorption spectrum reveals an absorption peak at 475 nm. Indicating that blue shift due to quantum confinement effect, as a result the direct energy gap is increased and found its value is 2.91 eV. Raman spectrum reveals the longitudinal optical phonon peaks are at 302 cm À1 and 603 cm À1. The noticeable asymmetry and frequency shift confirm the decrease in particle size. X-ray photoelectron spectroscopy reveals the surface composition and binding energy of elements and it confirm the presence of zinc. The photo-luminescence spectrum reveals an emission peak at 728 nm is analyzed. Zn doped cadmium sulphide thin film is useful for window material in solar cells and luminescent red phosphor.
Structural, Analysis and Optical Studies of Cadmium Sulfide Nanostructured
Procedia Engineering, 2013
Cadmium sulfide (CdS) thin films of nanostructure were prepared and deposited on glass substrates with Cd:S (1.2 to 0.05 mol/L) annealed at 400 ºC and different spin coating speed (1000 and 5000 rpm) using sol-gel spin coating technique. Structural, morphological and analytical studies were investigated by x-ray diffraction XRD, scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV-VIS Spectrophotometer. It is found that the average grain size of CdS thin films is 1.35 to 2.66 nm for the thin films prepared at 1000 and 5000 rpm respectively. The band gap was also calculated from the equation relating absorption coefficient to wavelength. The band gap indicates the film is transmitting within the visible range and the band gap changes because of the grain size of the CdS in the films. The effect of grain size on the semiconductor properties is under consideration. And the calculated results by specific models of refractive index are in agreement with experimental and theoretical data. The physical conditions were kept growing and identically.
The CdO:Co films have been deposited on substrate temperature at 400 °C by spray pyrolysis method using cadmium chloride and cobalt chloride as a precursors for Cd and Co ions, respectively. The effect of annealing temperature on optical constants of Co:CdO thin films are investigated using UV-Visible spectrophotometer in the range of (300-900) nm at room temperature. The absorbance and optical parameters such as α, n, ε1, ε2, and χ are increased when the annealing temperature increases, while the energy gap decreased from 2.5 eV before annealing to 2.48 eV after 500 °C annealing temperature. Urbach energy is increased with the increasing of annealing temperature from 353 meV for sample before annealing to 715 meV for the same samples annealed at 500 °C.
Studies on Cobalt Doped CDS Nanoparticles by Simple Co- Precipitation Route
this study examined the influence of the Co doping concentration on the structural and optical properties of Cd 1-x Co x S nanoparticles synthesized using simple Co-precipitation route at room temperature. The samples were characterized by X-ray diffraction and FTIR spectroscopy. From XRD patterns, Co doped CdS nanoparticles have cubic crystal structure with single in phase. The lattice constant and volume of unit cell were increased with increasing Co doping. The crystallite size of prepared nanoparticles increased with increasing Co content from 2.07 to 2.57 nm. The surface morphology of prepared samples was characterized by using scanning electron microscopy (TEM). The pure and Co doped CdS samples have spherical like structured. The dislocation density and strain was decreased with increasing Co doping. The functional groups of the nanoparticles have been identified by FTIR studies. The results showed that Co doping strongly affects the structural and optical properties CdS nanoparticles.
Solar Energy, 2012
Cadmium sulfide (CdS) nanostructures were deposited on glass substrates by sol-gel spin coating technique. X-Ray Diffraction (XRD) results have indicated that the formation of CdS has hexagonal structure. The lattice constants are investigated for CdS nanostructures deposited on glass substrates with different spin coating speeds. The thickness of CdS nanostructures as measured by the Atmoic Force Microscopy (AFM) and found to be in the range of 150 nm and 10 nm at 1000 rpm and 5000 rpm spin coating speed, respectively. The transmissions of CdS nanostructures are investigated systematically by Ultra Violet (UV-vis) spectrophotometer.
Optical and electrical characterization of cadmium selenide doped with cobalt
Journal of Physics and Chemistry of Solids, 2006
The optical and electrical properties of Co 2+ ions in CdSe have been investigated. Absorption, photoluminescence, electron paramagnetic resonance, and Hall measurements were used to characterize a cobalt-doped (1 Â 10 19 cm À3 ) single crystal. Infrared absorption and emission spectra associated with transitions between the 4 A 2 (F) ground state and the 4 T 1 (F) and 4 T 2 (F) excited states are described. At 10 K, spin-orbit splittings result in three structured absorption bands associated with the 4 A 2 (F) to 4 T 1 (F) transition having zero-phonon lines at 4926, 5101, and 5724 cm À1 . The 4 A 2 (F) to 4 T 2 (F) transition shows two zero-phonon lines at 2874 and 3286 cm À1 , also accompanied by vibronic structure. Intrinsic lattice modes explain most of the sharp-line structure observed at low temperature, except for a subset of peaks where local modes (25-30 cm À1 ) are invoked. Using below-band-gap light, selective excitation allows detection of the 4 T 1 (F) to 4 A 2 (F) recombination at liquid-helium temperatures. The activation of free carriers in our n-type material containing shallow donors is affected by the presence of cobalt, and we find the Co +/++ level to be about 34 meV below the conduction band of CdSe. r
Journal of Materials Science: Materials in Electronics, 2016
Inorganic binary and ternary compounds are considered as key materials in applications related to solar energy conversions. In this paper, we report on the chemical synthesis of ternary cadmium cobalt selenide thin film and studies on some of its properties. A cadmium cobalt selenide film of 0.92 lm thickness on glass substrate shows a uniform spherical morphology. An XRD analysis confirms the presence of individual cubic cadmium selenide and cobalt selenide phases formulated in a homogeneous, grainy morphology. The optical absorbance study gave a single absorption edge at *680 nm corresponding to optical band gap of 1.84 eV, while emission spectra exhibited a strong emission band at *675 nm at room temperature corresponding to a fundamental band gap. A photo-electrochemical cell constructed reports a conversion efficiency of 0.742 % with a fill factor of 37.70 %.
Journal of Asian Ceramic Societies, 2016
Transparent conducting Tin doped Cadmium oxide thin films were prepared by sol-gel spin coating method with different Sn concentrations. X-ray diffraction analysis reveals the polycrystalline nature of the Cadmium oxide (CdO) with cubic structure and show preferential orientation along (111) plane. The surface morphology of prepared films was analyzed by SEM and surface roughness variations analyzed by water contact angle measurement. The EDX spectra confirmed the presence of Cd, Sn and O elements in the films. The blue shift of energy gap from 2.42 to 2.96 eV is explained by Burstein-Moss effect. The presents of functional groups and the chemical bonding are confirmed by FTIR spectra. The minimum electrical resistivity (1.12 × 10 −4 cm) and maximum carrier concentration (9.94 × 10 21 cm −3) was obtained for 5% of Sn doped CdO thin film.