Microstructural, morphological and optical properties of sprayed thin films of indium doped gadolinium oxide (Gd

This paper featured a study on undoped and Indium doped Gadolinium oxide Gd2O3: In thin films, elaborated on a glass substrates at temperature of 500 °C by homemade Spray Pyrolysis technique, at different Indium concentrations as follow 0, 2, 4, 6 and 8 at %. This thin layers, where a subjects to a numerous characterization techniques to study the effect caused by introducing the dopant element “Indium” in Gadolinium oxide lattice on the structural properties (X-Ray Diffraction and Raman spectroscopy) and optical properties. The structural characterization carried by the X-ray diffraction (XRD) reveals a polycrystalline Monoclinic B-type structure for all Gd2O3:In thin films. Moreover, these findings are verified by the Raman spectroscopy results. Concerning the optical properties of our thin films, the optical measurements carried by UV-VIS-NIR spectrophotometer shows an increase in the transmittance value within the visible region [370-900 nm] and in the band gap energy value by raising Indium doping rate from 0 at % to 6 at %, also the disorder caused inside the thin films were estimated by the Urbach equation. That said, the 2 at % Indium doped gadolinium oxide thin film provides interesting results that can be applied in solar cells as an optical window material

Electrochemical behavior of spray deposited nickel oxide (NiO) thin film in Alkaline electrolyte

Nickel oxide (NiO) Thin film was successfully deposited on the glass substrate using an inexpensive spray pyrolysis (SP) technique. The structural, morphological, and optical properties have been studied, thus the electrochemical behavior of NiO film in Alkaline electrolytes has been investigated. The X-ray diffraction (XRD) analysis showed that NiO thin film exhibit a polycrystalline cubic rock-salt structure with a preferential orientation on the plane (111). This result was confirmed using Raman spectroscopy. The Scanning Electron Microscopy (SEM) images exhibit a smooth and dense surface without major cracks. Optical analysis shows an average transmission of about 55% in the visible light range, and the optical band gap energy was estimated by Tauc’s method and showed a value of 3,71 eV. Electrochemical properties as specific capacitance (Csp), optical density variation (ΔOD), and Coloration efficiency (CE) were studied using cyclic voltammetry in 1M KOH and 1M NaOH electrolytes. The results indicated that the behavior of the NiO layer in KOH is more effective than in NaOH electrolytes

Characterization of output circular polarization degree in lowcost asymmetric metasurfaces

Addition of asymmetry in plasmonic nanostructures can lead to chiro-optical phenomena, usually monitored as different absorption of left and right polarization, i.e. circular dichroism. Moreover, interesting features arise when the nanostructure changes the polarization state of the input beam. In this work, we perform extrinsic chirality characterization in a widely tuneable near-infrared range, by monitoring both polarization of the input and of the transmitted beam. We characterize low-cost metasurfaces based on polystyrene nanospheres asymmetrically covered by Ag, by exciting them at different angle of incidence with left, right and linear polarization. We then resolve the circular polarization degree of the transmitted beam, demonstrating resonance-governed circular polarization degree in the output, showing the interplay of both intrinsic and extrinsic chirality

Experiments and simulations of chiro-optical response in lowcost nanohole arrays in silver

2D metasurfaces based on periodic nanoholes in metal have been proposed in various plasmonic platforms. Specifically, their resonant features have led to applications spanning in biosensing. Here we investigate additional degree of freedom in elliptical nanohole arrays with hexagonal geometry: chiro-optical effects. Namely, the in-plane asymmetry and a slightly elliptical shape of nanoholes were previously shown to differently extinct light of opposite handedness, even at normal incidence. We now fully characterize nanoholes in Ag, fabricated by low-cost nanosphere lithography. We first measure the dependence of the transmitted intensity for opposite handedness, in a broad spectral and angle of incidence range. We then resolve the circular polarization degree of the transmitted light when the nanohole array is excited with linear polarization. Finally, we numerically investigate the origin of the chiro-optical effect at the nanoscale. We believe that circular polarization resolving of the transmitted degree could be further adapted as a highly sensitive tool in chiral sensing

Effect of in-doping on electrochromic behavior of NiO thin films

Undoped and Indium doped Nickel Oxide (NiO) thin layers with different doping content (2, 4, 6 at.%) were successfully deposited on glass and Indium-doped Tin Oxide (ITO) substrates using spray pyrolysis (SP) technique. The effect of indium on the microstructural, morphological, optical, and electrochromic behaviors of NiO films was investigated by X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy, UV–Vis-NIR spectrophotometry. XRD examination shows that all NiO layers have a polycrystalline cubic phase with a preferred orientation along the (111) plane. Raman spectroscopy proves the XRD result. SEM images show nanograins formation in all the sprayed films. The EDS analysis and the elemental mapping reveal the homogeneous distribution of the elements. The optical analysis reveals an average transmission of about 72% in the visible light region and an optical band gap energy of 3.54 eV for the undoped sample. These values decreased with increasing Indium content to reach 65% and 3.46 eV, respectively for the 6 at.% In-doped sample. The electrochromic behavior of NiO films deposited on ITO substrates was measured by cyclic voltammetry in a 2 M KOH aqueous electrolyte. The results show that a specific capacitance of 66 F. g − 1 at 5 mV.s − 1, an optical density variation of 43%, and a coloration efficiency of 93.74 cm2/C were obtained for 2 at.% In doped NiO. These values are considerably higher than those obtained for the undoped films, indicating that the In doping improved the electrochromic performance of nickel oxide films. © 202