Fluorine-doped Tin Oxide-coated Glass Substrates Research Articles

Thermal transport and optical anisotropy in CVD grown large area few-layer MoS2 over an FTO substrate

Atomically thin MoS2 is a promising candidate for its integration into devices due to its strikingly unique electronic, optical, and thermal properties. Here, we report the fabrication of a few-layer MoS2 thin film over a conducting fluorine-doped tin oxide-coated glass substrate via a one-step chemical vapor deposition method. We have quantitatively analyzed the nonlinear temperature-dependent Raman shift using a physical model that includes thermal expansion and three- and four-phonon anharmonic effects, which exhibits that the main origin of nonlinearity in both the phonon modes primarily arises from the three-phonon anharmonic process. We have also measured the interfacial thermal conductance (g) and thermal conductivity (ks) of the synthesized film using the optothermal Raman spectroscopy technique. The obtained values of g and ks are ∼7.218 ± 0.023 MW m−2 K−1 and ∼40 ± 2 W m−1 K−1, respectively, suggesting the suitability of thermal dissipation in MoS2 based electronic and optoelectronic devices. Furthermore, we performed a polarization study using the angle resolved polarized Raman spectroscopy technique under non-resonance and resonance excitations to reveal the electron–photon–phonon interaction in the prepared MoS2, based on the semi-classical theory that includes deformation potential and Fröhlich interaction. Our study provides much needed experimental information about thermal conductivity and polarization response in a few-layer MoS2 grown over the conducting substrate, which is relevant for applications in low power thermoelectric and optoelectronic devices.

Effect of deposition temperature on topography and electrochemical water oxidation of NiO thin films

The deposition temperature plays a significant role in controlling the crystallinity, morphology, and texture of thin films. Herein, we report the fabrication of nickel oxide thin films on a fluorine-doped tin oxide-coated glass substrate via a single-step aerosol-assisted chemical vapor deposition technique. Variable temperatures from 450 to 525 °C were used for the fabrication of these NiO thin films. The crystalline structure of nickel oxide thin films was determined by X-ray diffraction which showed cubic structure having space group Fm3m, and unit cell lattice parameters of a = b = c = 4.17 Å that crystallize preferentially along (200) plane. While the Raman spectroscopic study revealed the presence of peaks corresponding to nickel oxide structure. The surface chemical composition and oxidation states were investigated by X-ray photoelectron spectroscopy. Moreover, field-emission scanning electron microscopy aided in examining the temperature-dependent topography and microstructure of films. It was observed that when deposition temperature is increased from 450 to 525 °C, the bandgap energy decreased from 3.59 to 3.41 eV. The electrocatalytic activity for the oxygen evolution reaction was performed under alkaline conditions, using linear sweep voltammetry and cyclic voltammetry at different scan rates. Moreover, ohmic drop and charge transfer resistance are estimated by electrochemical impedance spectroscopy. The nickel oxide deposited at 500 °C showed the highest current density and the earliest onset overpotential as compared with other samples at different temperatures. Morphology-dependent catalytic activity is attributed to substrate temperature which significantly affects the growth of nickel oxide. Cyclic voltammetry reveals the Ni redox feature due to the active phase of nickel (oxy)hydroxide (NiOOH) and there was no significant current until 1.5 VRHE. Measurements of activity as a function of substrate temperature were consistent with the hypothesis that different morphology of the electrode exerts different charge transfer activation on nickel oxide. These results suggested that electrocatalysts coupled with controlled morphology can be tuned in terms of high performance, commercial applicability, and water-splitting devices.

Preparation and characterization of sodium dodecyl sulfate/Ag nanoparticles constituting branched microfibers

Branched microfibers of sodium dodecyl sulfate/Ag nanoparticles were synthesized using a nanosecond laser at a wavelength of 532 nm. The synthesis process was investigated at three laser intensities (0.38, 0.76, and 1.53 MW/cm2) and five exposure times (5, 15, 30, 45, and 60 min). At intensities of 0.38 and 0.76 MW/cm2, with increasing the exposure time, the number of nanoparticles increases until an exposure time of 30 min. Above this, exposure saturation of the number of Ag nanoparticles takes place. A similar effect was detected for the size of nanoparticles at these laser intensities. The saturation effect begins at 5 min of exposure for a laser intensity of 1.53 MW/cm2. The estimated nanoparticle size ranges from 116 to 120 nm based on the exposure time for a laser intensity of 0.38 and 0.76 MW/cm2, respectively. Scanning electron microscopy images at low magnification show the branched microfiber structure, while at higher magnifications, nanoparticles of Ag covering these microfibers appear. Electron dispersion x-ray spectroscopy confirmed the presence of Ag. X-ray diffraction results for the particles deposited on a fluorine-doped tin oxide-coated glass substrate were discussed.

Model-based analysis of the ferroelectric response of multiferroic (1-x)BiFeO3-xPbTiO3 solid solution thin films around morphotropic phase boundary

It is a challenging task to deposit single phase multiferroic (1-x)BiFeO3-xPbTiO3 (BF-xPT) solid solution thin films on Fluorine-doped tin oxide (FTO) coated glass substrate due to its high crystallization temperature. This study presents the preparation of BF-xPT solid solution thin films covering the morphotropic phase boundary (MPB) region. Films were prepared in ambient conditions via solution processing method on FTO coated glass substrate. Optical absorption in the visible region has been observed for intermediate compositions, promising for optoelectronic applications. The presence of multiple phases, strain, and finite-size effects results in structural complexities that have been discussed in detail. In addition to that, due to the presence of defects such as grain boundaries and porosity, considerable leakage in hysteresis loops has been observed. Linear capacitive and ferroelectric responses have also been observed, indicating that the films are composed of induced dipoles and ferroelectric domains, respectively. The origin of each mechanism has been discussed in detail. Model-based analysis was carried out to separate intrinsic ferroelectric switching by identifying MPB compositions exhibiting optimum results. Based on the intrinsic response MPB compositions are found to lie in the 0.35 < x < 0.45.

Morphological exploration of chemical vapor–deposited P-doped ZnO nanorods for efficient photoelectrochemical water splitting

Photoelectrochemical (PEC) water splitting is beneficial and has received attractive attention due to a greater potential to generate hydrogen and oxygen from water by using plentiful solar light to solve the problem of energy crisis. Various active semiconductor materials are used in PEC water splitting applications. Nevertheless, in past decades, most of the researchers suggested that titanium oxide (TiO2) is the best photoanode for this type of applications. Now, Zinc oxide (ZnO) is considered a perfect substitution to TiO2 due to its comparable energy band structure and superior photogenerated electron transfer rate. In this study, bare and phosphorous-doped ZnO nanorods were successfully developed on fluorine-doped tin oxide-coated glass (FTO) substrate by chemical vapor deposition. X-ray diffraction (XRD) pattern authenticated hexagonal structure formation with strong diffraction peak of (101), which showed that ZnO nanorods were perfectly developed along c axis. The optical and morphological properties were analyzed by UV–Vis and scanning electron microscopy images. The energy-dispersive X-ray spectra demonstrated that doping agent phosphorous was present in ZnO nanorods. The PEC properties of the developed ZnO nanorods were further investigated and obtained results suggested that a small amount of phosphorous-doped ZnO nanorods enhances their PEC performance.

Study of antimony selenide hole-transport material for Mo/Sb2Se3/MAPbI3/C60/GZO/Ag heterojunction planar solar cells

Antimony selenide (Sb2Se3) photovoltaic exhibits low energy band gap for effective wide solar spectrum utilization. A new heterojunction planar solar cell design has been investigated using thin Sb2Se3 hole-transporting material (HTM) layer between bi-layer molybdenum (Mo) electrode and CH3NH3PbI3 (MAPbI3) perovskite active absorbing layer. The solar cell structure was prepared as Mo/Sb2Se3/MAPbI3/C60/GZO/Ag on fluorine-doped tin oxide-coated glass substrate. Thus, the HTM layer, active absorbing layer, electron-transporting layer, transparent conductive oxide layer, and top electrode contact layer, has been made of Sb2Se3, MAPbI3, C60, gallium-doped zinc oxide, and silver, respectively. The Sb2Se3 HTM layers were also annealed at different temperatures of 300–600 °C. Scanning electron microscopy study showed improved crystal grains with the annealing temperature. This new heterojunction planar solar cell exhibited high power-conversion efficiency of 16.8% with the 200 nm Sb2Se3 HTM layer that was annealed at 600 °C. The device corresponding VOC, JSC, FF, Rs, and Pmax had been 1.07 V, 20.7 mA/cm2, 75.8%, 18.6 Ω, and 1.68 mW, respectively.

Comparative Study of Characteristics of Dye Sensitized Solar Cells Fabricated Using Substrates Coated with Fluorine Doped Tin Oxide and Titanium

Dye-sensitized solar cells (DSSCs) have attracted many researchers because it has potential to supplement and compete with other solar cell technologies like Silicon (Si) and Cadmium Telluride (CdTe). The fabrication of DSSCs requires a photo electrode and a counter electrode of transparent and conducting nature. The commercial DSSCs uses electrodes of fluorine doped tin oxide (FTO) glass substrates. These electrodes are expensive and hence, possible alternative materials that are cheaper and that would provide better performance under similar environmental condition should be explored. In this paper, titanium (Ti)-coated glass substrates were prepared and then used to prepare electrodes for fabricating DSSCs. Similarly, DSSCs were fabricated using electrodes of conventional FTO-coated glass substrates. Performance characteristics like cell efficiency (η%), fill-factor (FF), short circuit current density (JSC) and open circuit voltage (VOC) of both fabricated DSSCs were obtained using their respective J-V characteristic curves under similar illumination of 100 mW/cm2 and with comparable transmittance under the visible transmission spectrum of 300-850 nm. The obtained results showed that DSSCs prepared using electrodes of FTO coated glass substrates have 1.557 times better cell efficiency and 2.172 times better fill factor than that of DSSCs fabricated using electrodes of Ti-coated glass substrates.

The type-II n-n inorganic/organic nano-heterojunction of Ti[formula omitted] self-doped TiO[formula omitted] nanorods and conjugated co-polymers for photoelectrochemical water splitting and photocatalytic dye degradation

In this article, we have reported the synthesis of two organic semiconductors which are anthraquinone and benzothia/selenadiazole-based π-conjugated D–A1–D–A2 (D-donor, A-acceptor) type co-polymers. We have coupled these organic semiconductors with the Ti3+ self-doped TiO2 nanorods (Ti3+/TiO2 NRs)—grown on the fluorine-doped tin oxide-coated glass substrate—to get type-II n-n inorganic/organic nano-heterostructures (NHs). Ti3+ self-doping effectively produces oxygen vacancies which, in turn, incorporates many sub-bandgap states in TiO2—making them visible-light active. The NHs electrodes acting as the photo-anodes initiate water oxidation under the visible-light illumination. The NHs not only boost the visible-light absorbance but also owing to the advantageous type-II band alignments, expedite better delocalization and faster transportation of the photogenerated carriers. The NHs comprising of benzothiadiazole (TP1) have been found exhibiting better photoelectrochemical performances than the Ti3+/TiO2 NRs as well as the NHs comprising of benzoselenadiazole (TP2). The saturated photocurrent densities offered by the TP1 and TP2 NHs electrodes at 1 V vs Ag/AgCl are 0.50 mA/cm2 and 0.30 mA/cm2, respectively, signifying almost 466.7% and 233.3% increments over the photo-current density shown by the Ti3+/TiO2 NRs electrode at 1 V vs Ag/AgCl. As far as the overall photocatalytic activities are concerned, the TP1 NHs thin film has shown the best performance. The photocatalytic efficiency for both of the NHs thin films substantially augmented in the presence of 1 mM H2SO4. This phenomenon is attributable to the photochemical formation of H2O2 because of the structural uniqueness of the polymers. Besides, experiments with the electron and hole scavengers admit the photocatalytic reactions are mostly dominated by electron mediated routes for both of the NHs. The photogenerated electrons produce •OH radicals which govern the holistic degradation mechanism.

Fabrication and photoelectrochemical activity of hierarchically Porous TiO2–ZnO heterojunction film

For the first time, we report the fabrication of hierarchically (macro with nested meso) porous nanocrystalline TiO2–ZnO heterojunction film onto fluorine-doped tin oxide-coated glass substrate by colloidal crystal templating technique using poly(methyl methacrylate) (PMMA) spheres as template. Accordingly, the precursor solutions of titanium isopropoxide and zinc acetate dihydrate in the presence of Pluronic P123 were used to impregnate the individual solution into the template. Initially, nanocrystalline TiO2 inverse opal mesoporous film was deposited using the titanium precursor. The film was cured at 450 °C in an air atmosphere. A similar process was adopted to deposit nanocrystalline ZnO inverse opal mesoporous film onto the TiO2 to obtain hierarchically porous TiO2–ZnO heterojunction nanocrystalline film. Morphology of the fabricated films showed a periodic arrangement of macropores, whereas the microstructural analysis confirmed the presence of nested mesopores in the film network. Chemical interaction existed between TiO2 with ZnO forming the heterojunction film was ascertained by X-ray photoelectron spectroscopy. Light harvesting efficiency of the samples was studied, and the photoelectrochemical (PEC) performance of the hierarchically porous heterojunction films as photoanode showed about 5 times enhancement in photocurrent density compared to the pristine metal–oxide–semiconductor film under visible light exposure. The porous nanocrystalline hierarchically porous inverse opal heterojunction film could be used as an efficient photoanode in PEC cell.

Synthesis and characterization of CdTe thin film on FTO by electrodeposition technique for CdTe/CdS solar cells

In this work, the synthesis of the CdTe thin film (absorber layer) on fluorine-doped Tin oxide (FTO) substrate by electrodeposition technique of CdTe/CdS solar cell has been presented. As a result of the superior efficiency in energy conversion by absorbing energy in a broad range of the solar spectrum, thin film CdS/CdTe solar cells have been paid attention worldwide as a potential candidate for photovoltaics (PV). The electrodeposition (ED) technique is suitable for the synthesis of CdTe material due to its ease, low cost, scalability and manufacturability. Usually, the quality of these deposited thin films depends on several growth parameters, and the type of conducting glass substrate plays a crucial role. CdTe material grown up on the top of the FTO coated glass substrate having dimensions 75mm* 25mm*1mm and was characterized for its optical properties by UV-Vis spectrometer (UV-Vis), Photoluminescence (PL) and Fourier transform infrared spectrometer (FTIR). XRD result confirms the cubic crystalline character of the deposited material. The band gap of CdTe film estimated using Tauc’s plot is found to be 1.5eV. It is expected that this article will enrich the features of CdTe/CdS devices for solar energy conversion and stimulate further innovative research interest on this interesting topic.

Electrodeposited chromium-doped α-Fe2O3 under various applied potential configurations for solar water splitting

In this work, high quality hematite (α-Fe2O3) Chromium (Cr)-doped thin films have been synthesized via electrodeposition technique, on fluorine-doped tin oxide-coated glass substrates, under various applied potential configurations [cyclic voltammetry (CV), linear sweep voltammetry (LSV) and −0.5 V]. Chromium was added to the electrolyte at such a proportion that the Cr/(Cr + Fe) ratio remained within 8%. The as-deposited films were subsequently annealed in air at 650 °C for 2 h. Our novel study highlights the effect of using variable potential approaches during the film preparation on the properties of Cr-αFe2O3 deposited films. The prepared thin films were analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, UV–Vis absorption and photoelectrochemical (PEC) analysis. XRD revealed that samples are crystallized in Cr-Fe2O3 cubic structure with a crystalline orientation in the plane (1 1 1) and a clear improvement of the crystallinity and size crystallite of the Cr-Fe2O3 deposited using CV process. SEM micrographs showed that the morphology grains were three-sided pyramid-shaped, expanding with increase of the crystallinity. The calculated band gap values are 2.18, 2.23 and 2.20 eV, respectively for −0.5 V, LSV, CV. The Cr-Fe2O3 films synthesized in this study showed high PEC activity with very low carrier density in comparison with the conventionally electrodeposited films. This Cr-doped hematite films ‘excellent photoelectrochemical performance was mainly attributed to improved charge carrier properties. Such high photoactivity was attributed to the large active surface area and increased donor density caused by increasing the Cr doping in the α-Fe2O3 films.

Growth of ZnO nanorods on FTO glass substrate

A simple and direct method has been developed to grow zinc oxide (ZnO) nanorods (NRs) on a fluorine-doped tin oxide-coated glass (FTO) substrate. Firstly, spray pyrolysis deposition method is applied followed by dipping the substrate in a solution of ZnO growth reagents. The morphology, structure, and optical properties of the obtained thin film are investigated. The results demonstrate the successful synthesis of the ZnO NRs on FTO substrate. The NRs have a hexagonal rod like structure with diameter and length of 240 nm and 670 nm, respectively. FTO/ZnO NRs exhibited absorption of UV wavelengths and high transmittance in visible light region, with energy bandgap (Eg) of 3.2 eV. The characteristics of the FTO/ZnO NRs film can be explored in photovoltaic applications such as dye-sensitized solar cells.

Promising molybdenum trioxide films for optically detectable gas sensor and solar cell applications

Sub-stoichiometric molybdenum trioxide (MoO3−x) thin films were grown by thermal evaporation techniques on glass, single crystal silicon Si and Fluorine doped Tin Oxide (FTO) glass substrates with different thicknesses. It was found that, Oxygen vacancies play an important role on properties of MoO3−x films. The structural properties of these films were analyzed by means of x-ray diffraction, energy dispersive analysis of x-ray, scanning electron microscopy. The film surface uniformity and smoothness with thickness was tested using the surface roughness measurement for MoO3−x films grown on glass and FTO. The optical properties of all presented films were investigated using UV–vis–near-infrared (NIR) spectrophotometer Optical transmittance and reflection of MoO3−x film were measured in the wavelength range from 200 to 2500 nm. MoO3−x film with 500 nm thick was tested optically for gas sensor applications. The effect of chlorine exposure on the optical transmittance of MoO3−x film with 500 nm thick deposited on glass was studied. Transmittance degradation as increasing the period of exposure was observed, indicating to the high sensitivity of MoO3−x to chlorine gas. The electrical resistivity and Seebeck coefficient of MoO3−x film with 500 nm thick were measured. Low resistivity (∼10−3 Ω.cm) and high transmittance (∼78%) in the visible spectrum of the film of 100 nm thick deposited on FTO coated glass substrate recommended it to be promising as transparent conductive electrode for solar cell.

Electrodeposited Cr-Doped α-Fe2O3 thin films active for photoelectrochemical water splitting

Polycrystalline hematite (α-Fe2O3) Chromium (Cr)-doped thin films were electrodeposited on fluorine-doped tin oxide-coated glass substrates. The electrodeposition bath comprised an aqueous solution containing FeCl3·6H2O, NaCl, and H2O2.Chromium was added to the electrolyte at such a proportion that the Cr/(Cr + Fe) ratio remained within the 2–8 at. % range. The as-deposited films were subsequently annealed in air at 650 °C for 2 h. The structure and morphological characteristics of the undoped and Cr-doped α-Fe2O3 thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–Vis spectroscopy. Cr doping led the main XRD lines to shift to lower angles, which mostly resulted from substituting Fe3+ for Cr4+ ions that leads to α-Fe2O3 lattice contraction. The SEM observations showed that the roughness and aspect of surfaces changed with the Cr doping level. The photoelectrochemical (PEC) performance of the α-Fe2O3 films was examined by chronoamperometry and linear sweep voltammetry techniques. The Cr-doped films exhibited greater photoelectrochemical activity than the undoped α-Fe2O3 thin films. The highest photocurrent density was obtained for the 8% Cr-doped α-Fe2O3 films in 1 M NaOH electrolyte. All the samples achieved their best IPCE at 400 nm. The IPCE values for the 8 at.% Cr-doped hematite films were 20-fold higher than that of the undoped sample.This Cr-doped hematite films ‘excellent photoelectrochemical performance was mainly attributed to improved charge carrier properties. Such high photoactivity was attributed to the large active surface area and increased donor density caused by increasing the Cr doping in the α-Fe2O3 films.

Growth and morphology control of CH3NH3PbBr3 crystals

We present here an experimental study on the growth of CH3NH3PbBr3 crystals by conventional spin coating and simple drop casting methods. We observed directly that under the diffusion-limited regime, large-size cuboids and pyramid-like single crystals were obtained. Single-crystal X-ray diffraction revealed that these crystals were in the Pm-3m cubic crystalline structure phase, with a refined unit size of 5.93 A. Polycrystals with fractal-like or snowflake-like morphologies were grown by spin coating method, on fluorine-doped tin oxide-coated glass substrates, that we referred to as the attachment kinetics-limited regime. Interestingly enough, with the same technique, cuboids CH3NH3PbBr3 single crystals were obtained on bare glass substrates. These single crystals and polycrystals exhibited a very strong photoluminescence effect. This study paves a way for controlled growth of CH3NH3PbBr3 crystals and their advanced optoelectronic applications.

Photoelectrochemical performance of spray-deposited Fe-doped ZnS0.2Se0.8 thin films

Binary and ternary II–VI group semiconductor compounds are materials with potential use in various optoelectronic applications, including photoelectrochemical (PEC) solar cells. Thin films of ZnS0.2Se0.8 with various Fe-doping concentrations were successfully deposited on fluorine-doped tin oxide-coated glass substrates at a deposition temperature of 275 °C using the chemical spray pyrolysis. PEC cells with Fe:ZnS0.2Se0.8 thin film/1 M polysulphide/C (graphite) configurations were designed, and the effect of Fe doping on the PEC performance was studied. The results showed that Fe doping in ZnS0.2Se0.8 enhanced the performance of the PEC cells significantly. The optimum concentration was 0.20 mol%. The flat band potential and junction barrier height were maximum at this concentration, with values of −1.18 V and 0.27 eV, respectively. The junction ideality factors of the 0.20 mol% Fe-doped ZnS0.2Se0.8 thin film-based PEC cell in the dark and under illumination were found to be 1.21 and 1.17, respectively. The photovoltaic power output characteristics were boosted by Fe doping with a concentration of 0.20 mol%, with the open circuit voltage being 320 mV and the short circuit current being 1.48 mA cm−2. The solar-to-electrical conversion and the fill factor of the 0.20 mol% Fe-doped ZnS0.2Se0.8 thin film-based PEC cells were superior, with values of 2.84% and 0.60, respectively. A PEC cell with a 0.20 mol% Fe-doped ZnS0.2Se0.8 photosensitive thin film had the highest spectral sensitivity, at a wavelength of 375 nm, with an optical band gap of 3.30 eV.

Activating ZnO nanorods photoanodes in visible light by CdS surface sensitiser

Thin films of c-axis aligned uniform ZnO nanorods (NRs) were fabricated on to fluorine-doped tin oxide-coated soda lime glass substrate by a two-step chemical route. Thereafter ZnO NRs/CdS core shell structures were successfully synthesised by depositing CdS layer on top of vertically aligned ZnO NRs using less hazardous nanocrystal layer deposition technique. The presence of CdS in ZnO NRs/CdS core shell structures was confirmed by energy dispersive X-ray analysis. Examination of structure and morphology of the fabricated films by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) revealed that both films have one-dimensional hexagonal wurtzite structure. Optical properties evaluated from ultraviolet-visible and photoluminescence spectra demonstrated better photo response of ZnO NRs/CdS core shell structure with respect to bare ZnO NR structure. Optical to chemical conversion efficiency of ZnO NRs/CdS photoanode was found to be similar to 1.75 times higher than bare ZnO NRs photoanode in photo electrochemical water splitting under visible light.

CuIn(Se,S)2 Thin Films Synthesis and Characterization from a Single-Bath Electrodeposition Method

The manner in which CuIn(Se,S)2 thin films were synthesized using a one-step electrodeposition method from an electrolyte bath is described. These were deposited on fluorine-doped tin oxide-coated glass substrates. Cyclic voltammetry was used to assess the deposition process. The films were post-annealed in a vacuum atmosphere at 300°C for 1 h. The characterization techniques used in this study were x-ray diffraction, x-ray fluorescence, scanning electron microscopy, atomic force microscopy and UV–visible absorption spectroscopy. The characterization results show that the films have a good morphology, good crystalline structure, a high absorption coefficient close to the band edge, and bandgap energy of 1.44 eV. These properties are suitable for quality solar cell applications.

An investigation on the effect of substrate temperature and substrate type on physical properties of Sb2S3 thin films prepared by spray pyrolysis

In this work, the effect of substrate temperature and substrate type on physical properties of the Sb2S3 thin film were investigated. First, Sb2S3 thin films have been deposited by spray pyrolysis method using an aqueous solution of antimony chloride and thiourea on the glass at a substrate temperature of 240 °C to 330 °C. Then, the deposition process of this layer has been done on fluorine- doped tin oxide (FTO) coated glass at a constant temperature of 300 °C. The structural, surface morphological, optical and electrical characterizations of the samples were carried out using X-ray diffraction, field effect scanning electron microscope, UV–vis spectroscopy, and four-probe apparatus, respectively. X-ray diffraction analysis showed that by increasing substrate temperature, the amorphous nature of the Sb2S3 thin film changed to the polycrystalline structure. Also, while the layer/glass sample has an individual Sb2S3 (orthorhombic) crystalline phase, the band gap values for Sb2S3 thin films prepared by increasing substrate temperature varied from 1.68 eV to 1.75 eV. Data analysis showed the Sb2S3 thin film on both substrates had a relatively high absorption coefficient (∼105 cm−1) in the visible range, and the direct bandgap had a smaller value in the layer grown on glass compared to that grown on FTO coated glass substrate. Electrical measurements exhibited the Sb2S3/FTO sample had a lower sheet resistance and resistivity than the Sb2S3/glass sample.

Modification in the microstructural and electrochromic properties of spray-pyrolysed WO3 thin films upon Mo doping

WO3 thin films were grown onto the glass and fluorine-doped tin oxide-coated glass substrates using chemical spray pyrolysis technique. X-ray diffraction analyses reveal that all the films possess orthorhombic phase of WO3. Morphologies of the films have been found to vary with Mo-doping concentrations. Three-dimensional atomic force micrographs reveal that the 5 at% Mo-doped film has the maximum image surface area and is optimal for improved electrochromic performance. Cyclic voltammetry studies show that the cathodic and anodic peak current densities have the highest values for the 5 at% Mo-doped WO3 film. Relative to the undoped film, the change from coloured to bleached state is faster for the 5 at% Mo-doped WO3 film. Considering the reversibility and the switching response from chronoamperometry and the coloration efficiency from cyclic voltammetry, it has been concluded that the 5 at% Mo-doped WO3 film has an optimal electrochromic response.