Neha D. Desai

A facile and low cost strategy to synthesize Cd1−xZnxSe thin films for photoelectrochemical performance: effect of zinc content

In the present work, we report a facile chemical route for the deposition of Cd1−xZnxSe thin films using a simple, self-organized arrested precipitation technique (APT). The effect of Zn content on optical, structural, morphological, compositional and photoelectrochemical properties in Cd1−xZnxSe thin films was investigated. The optical properties and band gap profile of Cd1−xZnxSe thin films were varied with respect to Zn content. The estimated direct optical band gap was found to be in the range of 1.77 to 1.98 eV. X-ray diffraction (XRD) studies revealed that the films were nanocrystalline in nature with a pure cubic crystal structure and the calculated crystallite size lies in the range 36.5 to 66.3 nm. Scanning electron microscopy (SEM) demonstrates that the surface morphology can be improved with incorporation of Zn into the CdSe lattice. Compositional analysis of all samples was carried out using energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), which confirms the stoichiometric deposition of Cd1−xZnxSe thin films. J–V characteristics of all samples were studied in sulphide/polysulphide redox electrolyte. A high efficiency of 0.68% was observed due to lower crystallite size and higher surface area. These results show that by varying Zn content in Cd1−xZnxSe thin films, the photoelectrochemical performance can be enhanced.

Chemically Grown MoO3 Nanorods for Antibacterial Activity Study

In the present investigation, sea urchin like morphology of h-MoO3 nanorods are successfully synthesized by chemical bath deposition (CBD) technique. The thermal stability, structural details, morphology and compositional analysis of MoO3 was done using thermogravimetry (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) and X-ray photoelectron spectroscopy (XPS) techniques respectively. The thermal analysis reveals presence of sharp exothermic peak at 409oC indicating irreversible phase transition. X-ray diffraction pattern showed hexagonal to orthorhombic phase transition after annealing at 450oC. As synthesized h-MoO3 shows well oriented hexagonal rods with sea urchin like architecture while that of annealed MoO3 sample revealed 2D layer by layer growth. The SAED pattern confirms single crystalline nature of as synthesized h-MoO3 and polycrystalline nature of annealed α-MoO3. While XPS study of both confirms Mo+6 and O2- oxidation states of elements. Furthermore, characteristic antibacterial properties of h-MoO3 and α- MoO3 against gram positive Bacillus megaterium, Streptococcus aureus and gram negative Escherichia coli is noted.

Surfactant mediated synthesis of bismuth selenide thin films for photoelectrochemical solar cell applications

In the present report, nanostructured bismuth selenide (Bi2Se3) thin films have been successfully deposited by using arrested precipitation technique (APT) at room temperature. The effect of three different surfactants on the optostructural, morphological, compositional and photoelectrochemical properties of Bi2Se3 thin films were investigated. Optical absorption data indicates direct and allowed transition with a band gap energy varied from 1.4 eV to 1.8 eV. The X-ray diffraction pattern (XRD) revealed that Bi2Se3 thin films are crystalline in nature and confirmed rhombohedral crystal structure. SEM micrographs shows morphological transition from interconnected mesh to nanospheres like and finally granular morphology. Surface topography of Bi2Se3 thin films was determined by AFM. Compositional analysis of all samples was carried out by energy dispersive X-ray spectroscopy (EDS). Finally, all Bi2Se3 thin films shows good PEC performance with highest photoconversion efficiency 1.47%. In order to study the stability of Bi2Se3 thin films four cycles are repeated after gap of one week each. Further PEC performance of all Bi2Se3 thin films are also supported by electrochemical impedance (EIS) measurement study.

Single step fabrication of CuS thin film via hydrothermal route for solar cell application

In the present investigation, we have successfully synthesized Copper Sulfide (CuS) thin film via facile and low cost hydrothermal method. The synthesized (CuS) thin film was characterized for optical, morphological and compositional analysis. Surface profiler study shows thickness of thin film is 420 nm. The optical study revealed that the direct allowed type of transition having band gap 1.95 eV. The X-Ray diffraction (XRD) study illustrated that CuS thin film was nanocrystalline in nature with pure cubic crystal structure and calculated crystalline size is 18 nm. Well adherent and crack free deposition on substrate was observed in Scanning Electron Microscopy (SEM) analysis. SEM images show that synthesized CuS thin film having nanoflakes like morphology. The Energy Dispersive Spectra (EDS) pattern confirmed that Cu and S elements are present in deposited thin film. At last, we have critically analyzed photoresponse property to check the suitability of deposited materials for photoelectrochemical (PEC) application. PEC study illustrates that, the synthesized CuS thin film having power conversion efficiency 0.162 %.In the present investigation, we have successfully synthesized Copper Sulfide (CuS) thin film via facile and low cost hydrothermal method. The synthesized (CuS) thin film was characterized for optical, morphological and compositional analysis. Surface profiler study shows thickness of thin film is 420 nm. The optical study revealed that the direct allowed type of transition having band gap 1.95 eV. The X-Ray diffraction (XRD) study illustrated that CuS thin film was nanocrystalline in nature with pure cubic crystal structure and calculated crystalline size is 18 nm. Well adherent and crack free deposition on substrate was observed in Scanning Electron Microscopy (SEM) analysis. SEM images show that synthesized CuS thin film having nanoflakes like morphology. The Energy Dispersive Spectra (EDS) pattern confirmed that Cu and S elements are present in deposited thin film. At last, we have critically analyzed photoresponse property to check the suitability of deposited materials for photoelectrochemical (PEC)...