V.J. Fulari

Hierarchical 3D-flower-like CuO nanostructure on copper foil for supercapacitors

We report a trouble-free chemical synthesis of copper oxide (CuO) nanoflowers on flexible copper foil (Cu) and their use as electrodes for supercapacitors. Various characterization techniques, such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and Brunauer–Emmett–Teller (BET) analysis, have been used to characterize CuO nanostructure. Supercapacitive properties show that CuO electrodes exhibit a high specific capacitance of about 498 F g−1 at 5 mV s−1, with a high energy density of 26 W h kg−1 in KOH electrolyte. Moreover, impedance analysis showed lower ESR value, high power performance, and an excellent rate as well as frequency response for the CuO electrodes. The excellent electrochemical properties of the CuO electrodes indicate that they have many potential applications in high-performance supercapacitors.

Influence of Mn incorporation on the supercapacitive properties of hybrid CuO/Cu(OH)2 electrodes

Here, we are presenting the effect of Mn doping on the supercapacitive properties of CuO/Cu(OH)2 hybrid electrodes. Briefly, Mn doped CuO/Cu(OH)2 (Mn:CuO/Cu(OH)2) thin films have been synthesized by a successive ionic layer adsorption and reaction (SILAR) method which are further characterized by different physiochemical techniques. Our results revealed the formation of hybrid CuO/Cu(OH)2 thin films with significant morphological deviation through Mn doping. Moreover, considerable positive effect of Mn doping on the electrochemical properties of hybrid CuO/Cu(OH)2 electrodes have been witnessed. Later, the results suggest that at 3% Mn doping in CuO/Cu(OH)2 electrodes with nanoflower-like nanostructures exhibits the highest specific capacitance. The maximum specific capacitance achieved for a 3% Mn:CuO/Cu(OH)2 hybrid electrode is 600 F g−1 at 5 mV s−1 in 1 M Na2SO4 electrolyte. Additionally, a Ragone plot confirms the potential of the Mn:CuO/Cu(OH)2 hybrid electrode for electrical energy storage applications.

Photoelectrochemical cell studies of Fe2+ doped ZnSe nanorods using the potentiostatic mode of electrodeposition

The Fe(2+) doped ZnSe nanorods are synthesized using simple potentiostatic mode of electrodeposition on the ITO substrate. In order to study the doping effect of Fe(2+) in ZnSe, varied the doing percent such as 0.5%, 1%, 1.5%. These films are characterized for structural, compositional, morphological, optical and electrochemical properties using the X-ray diffraction study (XRD), X-ray photoelectron spectroscopy, field emission scanning electron microscopy, UV-vis spectroscopy and electrochemical spectroscopy. Along with these Raman spectroscopy and photoluminescence spectroscopy have been studied for understanding the characteristics vibrations of ZnSe and luminescence of ZnSe nanorods. FE-SEM shows the nanorods like morphology. Photoelectrochemical cell performance studied using the J-V measurement and it shows the maximum efficiency at 1% Fe(2+) doped ZnSe nanorods. The observed maximum efficiency of Fe(2+) doped ZnSe nanorods is 0.32%.

A nanostructured copper telluride thin film grown at room temperature by an electrodeposition method

Copper telluride onion flower like microstructures, constructed by quantum dots with various diameters, were obtained by a potentiostatic electrodeposition method at room temperature. The structural, optical, surface morphology, compositional analysis and Raman spectra properties of the deposited films have been studied using X-ray diffraction, optical absorption with scanning electron microscopy, EDAX, and Raman spectroscopy. The electrolyte concentration and deposition time can be used to control the diameter of the electrodeposited quantum dots to within a range of 50-55 nm. The films are found to be stoichiometric in composition. The optical constants such as the optical band gap energy and the optical absorption spectra show significant variation in their values with a change in deposition time. Upon deposition time the band gap energy increased from a value of 2.74 to 2.89 eV.

Propagation of Hermite-cosh-Gaussian laser beams in non-degenerate germanium having space charge neutrality

In this paper, we analytically investigate Hermite-cosh-Gaussian (HChG) laser beam propagation in non-degenerate germanium having space charge neutrality for the first three mode indices. The field distribution in the medium is expressed in terms of beam-width parameter f and decentred parameter b. The differential equations for the f parameter are established by a parabolic wave equation approach under paraxial approximation. Analytical solutions are obtained under the condition R n < R d , where R n is the self-focusing length and R d is the diffraction length. The behaviour of the f parameter with the dimensionless distance of propagation η for various b values is examined by numerical estimates. The results are presented graphically.

Electronic impurities (Fe, Mn) doping in CdSe nanostructures for improvements in photoelectrochemical applications

CdSe nanostructures (NSs) were tuned using different dopants (Fe:CdSe and Mn:CdSe) on electro-synthesized photoelectrochemical cells with fluorine-doped tin oxide (FTO) coated glass and stainless steel substrates. Thin films were characterized for their structural, morphological, and photoelectrochemical characteristics. Their optical and semiconducting parameters were also analyzed to determine the suitability of these films for photoelectrochemical (PEC)/solar cell applications. X-ray diffraction (XRD) analysis revealed that the films are polycrystalline in nature and suitable for improved solar cell applications. Scanning electron microscopy (SEM) studies illustrated that the thin films were adhered to the substrate uniformly and dopants were involved in the formation of novel nanostructured composition. Optical studies showed that the films are of direct band gap. For all the films, the semiconductor parameter values were in the better range of other transition metal chalcogenides, confirming that undoped CdSe and Fe:CdSe, Mn:CdSe thin films are capable as solar/PEC cell materials.

Structural, morphological, optical and photoluminescent properties of spray-deposited ZnSe thin film

ZnSe thin films are successfully deposited by spray pyrolysis deposition technique. Deposited thin films are characterized by X-ray diffraction study, and it reveals that spray-deposited ZnSe thin films are polycrystalline with hexagonal crystal structure. Surface morphology is carried out by scanning electron microscopy. It shows cotton-like morphology, and optical properties, such as absorbance, transmittance, reflectance, band gap, refractive index, extinction coefficient are studied. Photoluminescence shows strong emission at 497 nm. Also, spray-deposited ZnSe thin films are hydrophilic in nature, which is shown by contact angle meter.

Measurement of Properties of Copper Telluride Thin Films Using Holography

Abstract—Holography is a technique employed to make three dimensional images using electromagnetic waves. Holographic interferometry is one of the most important applications of holography. It is concerned with the formation and interpretation of fringe patterns, which appears when a wave generated at some earlier time and stored in a hologram is later reconstructed by interfering with comparison wave. We report a technique, which uses double exposure holographic interferometry together with simple mathematical interpretation, which allows immediate finding of stress, mass, fringe width and thickness of thin film. We tested different normalities of solutions. It is observed that increase in deposition time increases thickness and mass of thin film but decreases stress to substrate. The thin films are prepared using electrodeposition technique. The structural, optical and surface wettability properties of the deposited films have been studied using X-ray diffraction (XRD), optical absorption and contact angle measurement, respectively.

Analytical Study of HChG-Laser Beam Propagation in Collisional and Collisionless Plasmas

We have studied the propagation of m=0, 1 and 2 mode Hermite-cosh-Gaussian (HChG) laser beams in collisional and collisionless plasmas. The field distribution in the medium is expressed in terms of beam-width parameter f and decentred parameter b. The differential equations for f-parameter are established by parabolic wave equation approach under paraxial approximation. Analytical solutions are obtained under the condition Rn < Rd where, Rn is the self-focusing length and Rd is the diffraction length. The behaviour of f-parameter with the dimensionless distance of propagation η for various b-values is examined by numerical estimates. The results are presented graphically.

Study of Diffusion Process in Sucrose Solution by Using Double Exposure Holographic Interferometry (Dehi)

Holography is an interference method of recording the light waves diffracted by a subject illuminated with coherent light. Holographic interferometry is the most important and revolutionary application of holography. It is an extension of interferometric measurement technique in which at least one of the waves, which interfere, is reconstructured by hologram. It is concerned with the formation and interpretation of fringe patterns, which appear when a wave generated at some earlier time and stored in a hologram is later reconstructed by interfering with a comparison wave. The paper describes the use of holography in chemistry to study transport phenomena in transparent liquids. Diffusion is the movement of molecules due to their thermal energy under the influence of concentration gradient. we have employed DELHI technique for determining diffusion coefficient of 0.5 N sucrose solution. This technique resulted in producing good contrast fringes which are superior than reported earlier. The experimental results are compared with existing diffusion coefficient values and it is observed that there is good agreement with existing data.