Tin Oxide Covered Glass Substrates Research Articles

Improved Hydrogen Evolution Reaction Performance using MoS2–WS2 Heterostructures by Physicochemical Process

This report describes the synthesis of a layered molybdenum disulfide (MoS2)–tungsten disulfide (WS2) heterostructure onto fluorine doped tin oxide covered glass substrates using a combination of chemical bath deposition and RF sputtering techniques. FESEM images revealed that the MoS2–WS2 heterostructure surface consisted of a cauliflower structured array of grains with spherical structures. The vertically aligned atomic layers were explored by transmission electron microscopy images for MoS2–WS2 heterostructure. Hydrogen evolution reaction (HER) kinetics show overpotentials of 151 and 175 mV @ 10 mA/cm2 with Tafel slope values of 90 and 117 mV/decade for pristine MoS2 and WS2 electrocatalysts, respectively. Improved electrocatalytic activity for HER was established with overpotential 129 mV @ 10 mA/cm2 and Tafel slope 72 mV/decade for the MoS2–WS2 heterostructure. The MoS2–WS2 heterostructure electrocatalyst showed robust continuous HER performance over 20 h in an acidic solution. This improved electroc...

Structural, Optical, and Electrical Characteristics of Zinc Oxide and Copper Oxide Films and Their Heterojunctions

In this paper, n-Zinc oxide/p-copper oxide heterojunctions were fabricated by RF-sputtering on indium tin oxide-covered glass substrates. The structural and optical properties of the copper oxide and zinc oxide films were analyzed by X-ray diffraction, Fourier transform infrared, scanning electronic microscopy and ultraviolet-visible spectroscopy. The electrical junction properties were investigated by current–voltage (I–V) characteristics. Additionally, both capacitance (C) and conductance (G) versus frequency (f) measurements were realized at room temperature. The junctions showed a rectifying behavior, and C and G varied with both voltage and frequency.

Controllable Electrochemical Synthesis of Silver Dendritic Nanostructures and Their SERS Properties

Ag dendritic nanostructures were synthesized on fluorine-doped tin oxide covered glass substrates by the electrodeposition method. Results demonstrate that the size, diameter, crystallinity, and branch density of the Ag dendrites can be controlled by the applied potential, the surfactants and the concentration of AgNO3. Three kinds of typical silver dendrites were applied as substrates of the surface enhanced Raman scattering (SERS) and one of them was able to clearly detect rhodamine 6G concentrations up to 0.1 nmol/L. The differences of the SERS spectra at these Ag dendrites confirmed that the shapes and interparticle spacings have great effect on Raman enhancement, especially the interparticle spacings.

Time-resolved opto-electronic properties of poly(3-hexylthiophene-2,5-diyl): Fullerene heterostructures detected by Kelvin force microscopy

Thin blend polymer films made of poly(3-hexylthiophene-2,5-diyl) (electron donor) and fullerene derivatives as electron acceptors ([6,6]-thienylC61 butyric acid methyl ester and [6,6]-thienylC71 butyric acid methyl ester) are prepared by the spin-coating technique on indium tin oxide covered glass substrates. Time-resolved photo-induced changes of surface potentials are detected by Kelvin force microscopy (KFM). Changes of surface potentials by 10–150 mV reveal different quality and kinetics of charge generation in the two blends in short (minutes) and long (hours) time periods. This is attributed to a combination of electron accumulation, trapping, and organic material degradation under ambient conditions. As KFM characterizes the blend films directly without metal contact layer, it reveals differences in the opto-electronic behavior of the blends, which are not detected by common photovoltaic cell characterization.

Doped Nanostructured Zinc Oxide Films Grown by Electrodeposition

ZnO thin films doped with either In or Al are n-type oxide materials of interest for application in electronic devices and thin-film solar cells. In this work, the doped ZnO films were electrodeposited at 80 degrees C from an aqueous solution on polycrystalline conductive Indium Tin Oxide covered glass substrates. The incorporation of the dopants into the ZnO film has been verified by energy dispersive X-ray spectrum, X-Ray diffraction and optical transmission analysis. The optical and surface structure properties of the ZnO doped films are strongly affected by the In and Al concentrations in the electrodeposition solution as evidenced by optical transmission and reflection measurements, and scanning electron microscopy.

Inverted Solution Processable OLEDs Using a Metal Oxide as an Electron Injection Contact.

AbstractA new type of bottom‐emission electroluminescent device is described in which a metal oxide is used as the electron‐injecting contact. The preparation of such a device is simple. It consists of the deposition of a thin layer of a metal oxide on top of an indium tin oxide covered glass substrate, followed by the solution processing of the light‐emitting layer and subsequently the deposition of a high‐workfunction (air‐stable) metal anode. This architecture allows for a low‐cost electroluminescent device because no rigorous encapsulation is required. Electroluminescence with a high brightness reaching 5700 cd m–2 is observed at voltages as low as 8 V, demonstrating the potential of this new approach to organic light‐emitting diode (OLED) devices. Unfortunately the device efficiency is rather low because of the high current density flowing through the device. We show that the device only operates after the insertion of an additional hole‐injection layer in between the light‐emitting polymer (LEP) and the metal anode. A simple model that explains the experimental results and provides avenues for further optimization of these devices is described. It is based on the idea that the barrier for electron injection is lowered by the formation of a space–charge field over the metal‐oxide–LEP interface due to the build up of holes in the LEP layer close to this interface.

Dopamine/TiO 2 hybrid thin films prepared by the liquid phase deposition method

Liquid phase deposition method is applied to one-step production of a hybrid material composed by dopamine(DA) and TiO 2 anatase. An optimized amount of the enediol derivative is added to a fluoride titania precursor aqueous solution in order to entrap this modifier within the growing TiO 2, yielding a DA/TiO 2 nanocomposite material. Uniform, well-adhered and brown-colored thin films are deposited on indium tin oxide covered glass substrate. The DA/TiO 2 hybrid material has been characterized by infrared spectroscopy, electronic microscopy, X-ray diffraction and UV–vis spectroscopy. The formation of the hybrid material seems to be reasonably explained by linkage of different TiO 2 nanocrystallites taking advantage of both enediol and amine groups of DA.

Polypyrrole-poly(3-methylthiophene) bilayer films electrochemically deposited onto tin oxide

We report the electrochemical successive deposition of layers of polypyrrole and poly(3-methylthiophene), forming conjugated polymer heterostructures onto a tin oxide-covered glass substrate. The polymer bilayer thickness and roughness were determined as a function of deposition conditions, varying the sequence of deposition of the conjugated polymer layers. The charge transport characteristics of these bilayer devices were investigated and an effective charge carrier mobility of the order of 10–10 cm2 V–1 s–1 was determined.

Nucleation effects on structural and optical properties of electrodeposited zinc oxide on tin oxide

Zinc oxide was electrodeposited from oxygenated aqueous solutions of zinc chloride at 80 ∘C on tin oxide covered glass substrates. A new activation treatment for the substrate is established. This consists in the initial formation, in the deposition solution, of a thin metallic zinc layer (5–50 nm) converted to ZnO by in situ reoxidation. Variable densities of nucleation centers (with values approaching 1010 cm−2) are formed by this treatment. This allows control of the formation of a zinc oxide layer ranging from open deposits of isolated crystallites to compact and homogeneous layers. Compact layers have high specular transmission below the band gap value (∼3.5 eV), whereas open films exhibit extensive light scattering. The shapes of the current–time curves during deposition are discussed in terms of nucleation and structural effects. A possible influence of the semiconducting properties of the films is pointed out.

Electroluminescence from carbazole dimers

Blue light‐emission from a single‐layer organic LED (light‐emitting diode) based on carbazole dimers is reported. The device fabrication, involving vacuum sublimation of the dimer onto an indium tin oxide covered glass substrate, is described and the source of the electroluminescence elucidated. It is deduced that confined intra‐dimer luminescence excitations and a balanced double‐charge injection result in a device with good luminance and modest external quantum efficiencies. Of the three primary colors required for full‐color display applications, blue has been the most elusive to obtain.

Proton Diffusion in Tungsten Trioxide Thin Films

A small signal a‐c impedance method has been applied to the cell surface area carbon, in which the carbon electrode acts as a nonpolarizable electrode. Tungsten trioxide films were prepared by vacuum evaporation onto tin oxide covered glass substrate. The films, which were initially amorphous, were heated in air at temperatures from 300° to 400°C. The a‐c impedance measurements were carried out at several temperatures as a function of frequency from 10−2 to 105 Hz. The Randles circuit was fitted to the data by nonlinear chi‐squared minimization. The amorphous films have higher diffusion coefficients, i.e., about at 20°C, than crystalline samples, i.e., at 20°C. The activation energy for the amorphous sample is about 0.25 eV as compared to about 0.4 eV for crystalline films. Such a difference might be explained by a difference in composition and density between the amorphous and crystalline films or by different transport mechanisms such as hopping of H+ and diffusion of oxygen ion vacancies. The diffusion coefficient does not change significantly with composition in the range . The data suggest that may act as a nonblocking electrode with an exchange current density as high as 0.02 A · cm−2.