Analysis of optical dispersion parameters and electrochromic properties of manganese-doped Co 3 O 4 dendrite structured thin films

Nebulized spray pyrolysis method was employed to deposit pristine and manganese (Mn) -doped Co3O4 thin films for different Mn concentrations (4, 6 and 8 at.%). The structural properties revealed that the obtained films show predominant orientation along (311) plane and significant peak shift was observed upon an increase in Mn doping confirms the substitution of Mn in Co3O4 lattice. The pristine Co3O4 film shows clustered grains and dendrite patterns appearing with the increase in Mn content as evident from SEM studies. The optical dispersion parameters of the prepared films of pristine and Mn doped Co3O4 films were determined from UV transmission spectra. The phase purity and elemental analysis of the films revealed single phase with better stoichiometric films were obtained. The XPS core level spectra of 6 at.% Mn doped Co3O4 films exhibited the presence of two different oxidation states (Mn2+ and Mn3+). The electrical resistivity of the films decreased with increase in Mn dopant concentration was observed from linear four probe method. The Co3O4 film deposited using 6 at.% of Mn exhibited a maximum optical modulation of 35% and coloration efficiency of 29 cm2/C

Solvent volume dependent physical properties and electrocatalytic ability of nebulizer spray deposited CuInGaS 2 counter electrode for dye-sensitized solar cells

CuInGaS2 (CIGS) thin films were coated using nebulizer spray technique for different solvent volumes (10, 30, 50 and 70 ml) at the substrate temperature of 350 °C. The structural, optical and electrical properties were studied for the prepared CIGS thin films. CIGS thin films exhibited tetragonal structure and the maximum crystallite size was calculated for the film deposited using 50 ml solvent volume. The surface morphology of CIGS thin films was analyzed from scanning electron microscopy and atomic force microscopy studies. The electrical parameters of CIGS thin films such as resistivity, carrier concentration and mobility were examined using four probe method and Hall measurements. Electrocatalytic activities of the CIGS films towards redox couple (I−/I3−) were analyzed by cyclic voltammograms, electrochemical impedance spectroscopy, and Tafel polarization measurements. The high photocurrent efficiency was obtained for the CIGS counter electrode prepared using 50 ml solvent volume

Solvent volume-driven CuInAlS2 nanoflake counter electrode for effective electrocatalytic tri-iodide reduction in dye-sensitized solar cells

The influence of solvent volume on the properties of CuInAlS2 (CIAS) thin films deposited using simple and cost-effective nebulizer spray technique is studied. The polycrystalline CIAS thin films with tetragonal structure have been observed from the XRD results. SEM images show nanoflake-like structure on the film surface. The elemental presence and its chemical composition were examined by XPS and EDS. The deposited CIAS film for different solvent volume exhibited p-type semiconductor. Cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization measurements demonstrated that CIAS counter electrodes are capable of tri-iodide reduction process. The performances of photocurrent density-voltage for the CIAS CE exhibited the maximum efficiency of 2.55% with the short-circuit current density of 7.22 mA cm−2

Low-cost and eco-friendly nebulizer spray coated CuInAlS 2 counter electrode for dye-sensitized solar cells

CuInAlS2 thin films for different substrate temperatures were deposited by a novel nebulizer spray technique. The polycrystalline CIAS thin film exhibited tetragonal structure with the preferential orientation of (1 1 2) plane. Nanoflakes were observed from the surface morphology of CIAS film. The peak position of core level spectra confirms the presence of CuInAlS2 from XPS analysis. The absorbance spectra and optical band gap were observed from the optical property. The activation energy, carrier concentration, hole mobility and resistivity were determined by linear four probe and Hall effect measurements. The CIAS film was used as a counter electrode (CE) in dye-sensitized solar cells (DSSCs) and is characterized by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel measurements. DSSC fabricated with the CIAS CE achieved the photo conversion efficiency of about 2.55%

Facile preparation of hierarchical nanostructured CuInS2 counter electrodes for dye-sensitized solar cells

CuInS2 (CIS) thin films have been synthesized onto the glass substrates for different solvent volumes (10, 30, 50 and 70 ml) by nebulizer spray technique. The effect of solvent volume on the structural, morphological, compositional, optical and electrical properties of CIS thin films has been investigated. X-ray diffraction patterns suggest that the obtained CIS films are polycrystalline with the tetragonal structure. The surface morphology of the prepared CIS films purely depends on the solvent volume. The elemental quantitative investigation and the stoichiometric ratio of the CIS thin films were verified from XPS and EDS. High absorbance with the optical band gap of 1.13 eV was obtained at the higher solvent volume. All the deposited CIS thin films exhibited p-type semiconducting behavior with the high electrical conductivity and carrier concentration. CIS thin films deposited onto the FTO substrate were used as a counter electrode (CE) in dye-sensitized solar cells. CIS CEs possessed high electrocatalytic behavior and fast electron charge transfer at the CE/electrolyte interface. The CIS CE prepared using 50 ml solvent volume generated high energy conversion efficiency of about 3.25%

Defect engineering and opto electronic property modifications by 1.5MeV Li+ implantation on nano crystalline MgIn2O4 thin films

Spinel MgIn2O4 thin films were deposited on quartz substrates by the chemical spray pyrolysis technique using metal organic precursors at 450◦C. Energetic 1.5MeV Li+ ions were implanted to various fluences of 1013, 1014 and 1015 ions/cm2 onto insulating MgIn2O4 films using a 9 SDH-2, NEC, 3MV accelerator to modify the material properties and surface nature. X-ray diffraction analysis was carried out to identify the changes in the crystallinity and grain orientations before and after implantations. Before implantation, the grains of polycrystalline MgIn2O4 were randomly oriented [(222), (311), (442) and (511)], and after implantation they exhibited a tendency to realign the crystallites along the even (hkl) planes [(222) and (442)]. On the Li+-implanted sample, one or more grains combine together and form bigger grains along with shallowpits, as observed through the atomic force micrographs. The as-deposited films have a percentage transmittance of 70–80% in the wavelength range 400–800 nm and the observed optical transmittance was less in Li+-implanted MgIn2O4 films. The index of refraction and the extinction co-efficient values were respectively n = 1.98 and k = 10−2 in the visible region. However, the DC electrical conductivity of Li+-implanted films to a fluence of 1015 ions/cm2 was nearly 0.7 S/cm at room temperature. The efficiency of the carrier generation was increased from 13.41% to 26.81% on annealing the implanted sample to lower fluence (1013 ions/cm2)

Synthesis and characterization of spray pyrolysed MgIn2O4 spinel thin films for novel applications

A novel ternary oxide compound magnesium indate film, MgIn2O4 (MIO), manifesting high transparency and conductivity has been prepared by spray pyrolysis technique. Stoichiometrically mixed precursors were thermally sprayed onto glass substrates and decomposed at 400 and 450 1C and the growth parameters were studied in detail. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) studies have been conducted to confirm the formation of stoichiometric films. The dc electrical conductivity of these films was measured in the temperature range between 30 and 100 1C by four-probe technique. Measurement of Hall coefficient showed n-type electrical conduction and high-carrier concentration. Optical properties were studied in the wavelength range 280–1500nm and surface morphology of the MIO films were analyzed by scanning electron microscopy (SEM) and, atomic force microscopy (AFM)

Magnesium indium oxide (MgIn2O4) spinel thin films: Chemical spray pyrolysis(CSP) growth and materials characterizations

MgIn2O4, which has an inverse spinel structure, has been adopted as the transparent material in optoelectronic device fabrication due to its high optical transparency and electrical conductivity. Such a technologically important material was prepared by the spray pyrolysis technique. Precursors prepared for the cationic ratio Mg/In = 0.5 were thermally sprayed onto glass substrates at 400 and 450 ◦C. We report herein the preparation and characterization of the films by X-ray diffraction (XRD), energy-dispersive absorption X-ray spectroscopy (EDAX), and atomic force microscopy (AFM). The XRD results showed the single phase formation of the material that revealed the presence of Mg2+ and In3+ in the inverse spinelrelated structure. The FTIR and EDAX results further confirmed that the nanocrystalline films were mainly composed of magnesium, indium, and oxygen, in agreement with XRD analysis. We surmised from the AFM micrographs that the atoms have enough diffusion activation energy to occupy the correct site in the crystal lattice. For the 423-nm-thick magnesium indium oxide films grown at 400 ◦C, the electrical conductivity was 5.63× 10−6 Scm−1 and the average optical transmittance was 63% in the visible range (400–700 nm). Similar MgIn2O4 films deposited at 450 ◦C have a conductivity value of 1.5×10−5 Scm−1 and an average transmittance of 75%. Hall coefficient observations showed n-type electrical conductivity and high electron carrier concentration of 2.7×1019 cm−3