Search

Graphical abstract Highlights • Ti doped CdO is firstly reported for electrochemical non-enzymatic H 2 O 2 sensor applications. • Fabricated nanostructured thin films were directly exploited as working electrodes toward the detection of harmful H 2 O 2 gas. • Ti: CdO film exhibits pronounced electrocatalytic activity for the reduction of H 2 O 2 when compared to pure CdO. Abstract A new material, Ti doped CdO (Ti: CdO) semiconductor, is firstly reported by this work for electrochemical non-enzymatic hydrogen peroxide (H 2 O 2) sensor applications which was deposited by a simple, versatile and cost-effective chemical spray pyrolysis method on indium doped tin oxide (ITO) substrate. In the basic studies, first, the withstanding of cubic crystal phase along with worthy crystalline nature is discerned on CdO film after Ti doping, here only the preferentially orientated (200) diffraction plane shifted to (111). Subsequently, the irregular spherically shaped CdO nanoparticles (NPs) morphology changed as nearly uniform size with Ti doping is noticed under thermal pyrolytic decomposition process. The existence of Ti atoms in Ti: CdO film is authentically identified and confirmed using EDX and XPS studies respectively. The absorption and emission properties of CdO and Ti: CdO films are studied and confirmed their narrow band gap nature. Importantly, the Ti: CdO film shows pronounced electrocatalytic activity for the reduction of hydrogen peroxide (H 2 O 2) than pure CdO. Hence, the non-enzymatic electrochemical sensing of Ti: CdO electrode shows a lower detection limit, broad linear range, rapid response time and high sensitivity toward H 2 O 2 detection. This result will boost exploring a new opportunity for the deposition of other metal oxides and semiconductors by using a simple chemical spray pyrolysis method for detection of non-enzymatic H 2 O 2 sensor applications. [ABSTRACT FROM AUTHOR]

Abstract Quaternary Cu 2 ZnSnS 4 (CZTS) thin films with different S/(Cu+Zn+Sn) molar ratio have been deposited by homemade chemical spray pyrolysis unit. Secondary phase formation in CZTS thin films with respect to various S/(Cu+Zn+Sn) molar ratio was investigated. XRD and micro Raman results revealed that CZTS thin films belongs to kesterite crystal structure with a preferred orientation along (1 1 2) plane. Films deposited at x = 2, 1.72, 1.33 contain binary and ternary phases in addition to CZTS. High purity single phase CZTS was obtained at x = 0.80. The surface morphology of the films is found to be smooth. The optical absorption spectra showed that the absorption coefficient of the CZTS thin films is larger than 104 cm−1 in the visible region and the optical band gap varies from 2.05 eV to 1.45 eV. CZTS thin films were used as a photocatalyst to examine the effect of secondary phases in the decolorization of the Rhodamine B (RhB) dye under visible light. It was found that the presence of secondary phase significantly affects the photocatalytic performance of CZTS thin films. [ABSTRACT FROM AUTHOR]

Transparent conducting cadmium oxide (CdO) and Fe (0.5, 1, 1.5 and 2 wt%) doped CdO thin films were deposited on glass substrate using facile chemical spray pyrolysis technique. The influence of Fe doping on the structural, morphological, optical and electrical properties of CdO thin films were systematically investigated using different characterization techniques such as X-ray diffraction (XRD), atomic force microscope (AFM), UV–vis transmittance and Hall measurement respectively. The XRD patterns clearly reveal the pure and Fe doped CdO films are polycrystalline nature along with cubic crystal structure. AFM images show the roughness of the CdO thin film decreases with respect to Fe doping concentration. The surface structure of the 1 wt% Fe doped CdO film was investigated by X-ray photoelectron spectroscopy (XPS). Optical transmittance of the CdO thin film decreases with increasing of Fe doping concentration. The optical band gap value of the CdO thin film gradually decreases from 2.61 to 2.18 eV with increasing Fe doping concentration. From Hall measurement, the minimum value of resistivity is obtained for (7.67×10 −4 Ω cm) 1 wt% of Fe doped CdO thin film. Finally, the ethanol sensor behaviour was observed using home-built sensor unit. The maximum ethanol gas response of 56.12% is observed for 1 wt% of Fe doped CdO thin films. This result suggests the Fe doped CdO is one of the promising material in sensor applications. [ABSTRACT FROM AUTHOR]

Transparent and conducting cadmium oxide (CdO) and manganese doped CdO (Mn: CdO) thin films were deposited using a low cost spray pyrolysis method on the glass substrate at 300 °C. For Mn doping, various concentrations of manganese acetate (1–3 wt%) was used in the spraying precursor solution. The structural, electrical and optical properties of CdO and Mn: CdO films were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), UV–vis and Hall measurement. X-ray diffraction study reveals that the CdO and Mn: CdO films are possessing cubic crystal structures. SEM and AFM studies reveal that the grain size and roughness of the films are increased with increasing Mn doping concentration. Optical transmittance spectra of the CdO film decreases with increasing doping concentration of manganese. The optical band gap of the films decreases from 2.42 eV to 2.08 eV with increasing concentration of manganese. A minimum resistivity of 1.11×10 −3 Ω cm and maximum mobility of 20.77 cm 2 V −1 s −1 is achieved for 1 wt% of manganese doping. [ABSTRACT FROM AUTHOR]

Abstract: Dense rutile TiO2 nanorods were grown on an anatase TiO2 seed layer by a wet-chemical approach in which the nuclei layer was prepared by the chemical spray pyrolysis technique. Structural, morphological, and optical properties of prepared samples were investigated using X-ray diffraction (XRD), micro-Raman, scanning electron microscopy (SEM), atomic force microscopy (AFM), UV–vis spectroscopy, and fluorescence spectroscopy. From XRD, a clear authentication that, the preferentially oriented (101) crystallographic planes indicate that the rutile TiO2 nanorods are standing randomly along the normal to the substrate surface. Anatase TiO2 seed layer and rutile nanorods structural phases are clearly confirmed by micro-Raman measurement. SEM and AFM studies reveal that the TiO2 seed layer consists of high density nanoparticles with the thickness of 0.15μm and the height of the as-grown nanorods is ~0.6μm. The band gap energy of the anatase TiO2 seed layer and rutile as-grown nanorods is calculated using UV–vis absorption spectra and the band gap values of seed layer and nanorods are 3.21eV and 2.95eV respectively. The crystal defects of prepared films are measured using photoluminescence spectra. [Copyright &y& Elsevier]

Highlights: [•] Liquid Crystal Variable Retarders were characterized for operation. [•] Multi-slit spectrograph was calibrated for spectral resolution of 18mÅ. [•] Polarimeter package and CCD detector integrated using LabVIEW. [•] Linear polarization was successfully measured with multi slit spectropolarimeter. [ABSTRACT FROM AUTHOR]

Highlights • Highly transparent and conducting ZnO thin films have been optimized by Al doping. • Prepared films exhibit good optical transmittance ∼90–95% in the visible energies. • High conductivity (0.26 mho cm−1) and low resistivity (3.8 Ω cm) has been found in 2 wt% AZO film. • Solar cell configuration with SLG/Mo/CuInS 2 /CdS/iZnO/2 wt% AZO/Ag is delivered, 2.20% PCE. • This is superior to all other cells and especially 53% higher than that of the pristine ZnO. Abstract ZnO thin film with flake-like surface morphology has been optimized by Al doping via the home-built chemical spray pyrolysis technique at substrate temperature 250 °C. Then, its performance as an anti-reflecting as well as highly transparent and conducting window layer in CuInS 2 based solid-state solar cell is explored here. The solid-state properties of the pristine and Al-doped ZnO (AZO) thin films have been studied to determine its potential for use in photovoltaic applications. First, it substantiates that the Zn, O and Al atoms are mainly involved for the growth of hexagonal wurtzite crystal structure by EDAX, XPS and XRD studies. All the films exhibit good optical transmittance nearly ∼90–95% in the visible energy region. Further, the 2 wt% AZO film shows low reflection loss in the same region. The decreased electron forbidden gap size is noticed in Al doped ZnO as compared to pure ZnO film. The good electrical parameters i.e., high conductivity (0.26 mho cm−1) and low resistivity (3.8 Ω cm) are found in the 2 wt% AZO film. Wettability test confirms the 2 wt% AZO flake-like surface morphology exhibited hydrophobic nature. Eventually, the 2 wt% Al-doped ZnO flake-like morphology thin film utilized as a window layer in CuInS 2 based solid-state solar cell which exhibits a pronounced photocurrent density result in 2.20% power conversion efficiency (PCE) is achieved. This efficiency is superior to all others and 53% higher than that of pristine ZnO window layer based photovoltaic cell. [ABSTRACT FROM AUTHOR]

The study of polarized sunlight scattered from planetary atmospheres provides diagnostic tools that can help explore the possible composition and size distribution of clouds and aerosol particles. Previous studies have shown the potential of this technique in studying Water clouds on Earth and in the discovery of Sulphuric Acid clouds on Venus. The atmosphere of Mars is unique as it hosts three different types of aerosols: water (H 2 O) ice, carbon dioxide (CO 2) ice and dust. We considered scenarios analogous to Martian conditions and calculated the single and multiple scattering polarization for Martian dust, water ice and carbon dioxide ice with the help of a Radiative Transfer algorithm for Nadir and Limb spacecraft observation positions. The polarization features (-Q/I) of Mars atmosphere have low amplitude and have been found to be within the range of ±0.1 in the Nadir/Limb geometry for the spherical, spheroidal and cylindrical shapes considered here. We study its dependence upon the observation geometry, shape, size and composition of the scatterer. Future spacecraft studies of microphysical properties of dust and clouds through polarization will reveal the nature of condensation processes active in the Martian atmosphere. • A detailed theoretical study of polarization signatures of Mars atmosphere. • Consideration of various size distributions, shapes and atmospheric configurations (like dust or clouds). • Mars atmospheric polarization (-Q/I) is found to be constrained within +0.1 to −0.1 in near infrared for various observation geometries and shapes of the dust and clouds. • Non-spherical particle shapes (more likely for solid aerosols of Mars) offering large polarization features at around 90° scattering angles, which is missed by Earth based observations, can be effectively probed by spacecraft observation. • These predictions will help future exploration of Mars atmosphere for better understanding of dust and clouds. [ABSTRACT FROM AUTHOR]

Cadmium oxide (CdO) thin film was optimized on glass substrate at 250 °C using a chemical spray pyrolysis (CSP) technique followed by Al atoms doped into it with various wt% in order to study its influence on structural, electrical, optical, morphological and gas adsorption properties of the CdO thin films. All the films are deposited in polycrystalline cubic crystal phase is confirmed by XRD. The 90% of the visible as well as near infrared (650–850 nm) region energies is transmitted in pure and Al doped CdO films. Smooth surfaces and spherical shaped nanoparticles morphologies are conspicuous in CdO films after Al doping. The prepared CdO film is of n-type conductivity with having mobility of 64.4 cm2 V-1s-1 and carrier concentrations of 2.2 ×1020 cm-3. Importantly, the mobility increases and resistivity decreases is observed on CdO film as for Al doping level. After procuring some interesting physicochemical properties in CdO films by Al doping, trimethylamine (TMA) gas sensing analysis has been scrutinized using a simple and cost effective route. Finally, it is found that low resistive and high mobility of 1.5% Al doped CdO film exhibited pronounced sensitivity, 32.12%, is due to its higher specific surface area and as well as existence of more defective sites. [ABSTRACT FROM AUTHOR]