Inclined Substrate Deposition of Nanostructured TiO2 Thin Films for DSSC Application

Nanostructured TiO2 films were deposited onto Indium Tin Oxide (ITO) and glass substrates by dc reactive magnetron sputtering at different substrate inclination angles. The structural and optical properties of the deposited films were studied by X-ray diffraction, scanning electron microscopy and UV-Vis spectrophotometer, respectively. Dye-sensitized solar cells (DSSC) were assembled using these TiO2 films as photoelectrodes and the effect of the substrate inclination angle in the preparing process of TiO2 films on the DSSC conversion efficiency was studied.info:eu-repo/semantics/publishedVersio

Blocking layer effect on dye-sensitized solar cells assembled with TiO2 nanorods prepared by dc reactive magnetron sputtering

Three different thickness dense TiO2 (150 nm, 300 nm and 450 nm respectively) films were deposited on ITO substrates by dc reactive magnetron sputtering technique. These dense TiO2 films were used as the blocking layers. After that, TiO2 nanorod films were deposited on these dense TiO2 films by same technique. Both the dense and nanorod TiO2 films have an anatase phase. The dense TiO2 films have an orientation along the [101] direction and the TiO2 nanorod films show a very strong orientation along the [110] direction. These TiO2 materials were sensitized by N719 dye and the DSSCs were assembled using them as photoelectrode. The effect of the blocking layer on the efficiency of the DSSCs is discussed. The DSSC assembled using TiO2 nanorod film with 300 nm thickness blocking layer shows a high efficiency of 2.07%

The control of the diameter of the nanorods prepared by dc reactive magnetron sputtering and the applications for DSSC

The TiO2 nanorod arrays, with about 1.8 μm lengths, have been deposited on ITO substrates by dc reactive magnetron sputtering at different target-substrate distances. The average diameter of these nanorods can be modified from about 45 nm to 85 nm by adjusting the target-substrate distance from 90 mm to 50 mm. These nanorods are highly ordered and perpendicular to the substrate. Both XRD and Raman measurements show that the nanorods prepared at different target-substrate distances have only an anatase TiO2 phase. The nanorods prepared at the target-substrate distance less than 80 mm have a preferred orientation along the (220) direction. However, this preferred orientation disappears as the target-substrate distance is more than 80 mm. These TiO2 nanorods have been used as the electrodes for dye-sensitized solar cells (DSSC). The highest conversion efficiency, about 4.78%, has been achieved for TiO2 nanorods prepared at 80 mm target-substrate distance.SFRH/BSAB/862/2008, FCT, Portuga

Growth and characterization of Bi2Se3 thin films by pulsed laser deposition using alloy target

Bi2Se3 thin films were deposited on the (100) oriented Si substrates by pulsed laser deposition technique at different substrate temperatures (room temperature – 400 ºC). The effects of the substrate temperature on the structural and electrical properties of the Bi2Se3 films were studied. The film prepared at room temperature showed a very poor polycrystalline structure with the mainly orthorhombic phase. The crystallinity of the films was improved by heating the substrate during the deposition and the crystal phase of the film changed to the rhombohedral phase as the substrate temperature was higher than 200 ºC. The stoichiometry of the films and the chemical state of Bi and Se elements in the films were studied by fitting the Se 3d and the Bi 4d5/2 peaks of the X-ray photoelectron spectra. The hexagonal structure was seen clearly for the film prepared at the substrate temperature of 400 ºC. The surface roughness of the film increased as the substrate temperature was increased. The electrical resistivity of the film decreased from 1x10-3 to 3 x 10-4 Ω cm as the substrate temperature was increased from room temperature to 400 ºC.Shenyang National Laboratory for Material Science (SYNL), Chin

The effect of hydroxyl on dye-sensitized solar cells assembled with TiO2 nanorods

TiO2 nanorods have been prepared on ITO substrates by dc reactive magnetron sputtering technique. The hydroxyl groups have been introduced on the nanorods surface. The structure and the optical properties of these nanorods have been studied. The dye-sensitized solar cells (DSSCs) have been assembled using these TiO2 nanorods as photoelectrode. And the effect of the hydroxyl groups on the properties of the photoelectric conversion of the DSSCs has been studiedinfo:eu-repo/semantics/publishedVersio

Effect of the oxygen flow on the properties of ITO thin films deposited by ion beam assisted deposition (IBAD)

ITO films were deposited onto glass substrates by ion beam assisted deposition method. The oxygen ions were produced using a Kaufman ion source. The oxygen flow was varied from 20 until 60 sccm and the effect of the oxygen flow on properties of ITO films has been studied. The structural properties of the film were characterized by X-ray diffraction and atomic force microscopy. The optical properties were characterized by optical transmission measurements and the optical constants (refractive index n and extinction coefficient k) and film thickness have been obtained by fitting the transmittance using a semi-quantum model. The electrical properties were characterized by Hall effect measurements. It has been found that the ITO film with low electrical resistivity and high transmittance can be obtained with 40 sccm oxygen flow (the working pressure is about 2.3 × 10−2 Pa at this oxygen flow).Fundação para a Ciência e a Tecnologia (FCT) - SFRH-BSAB-514

Study of vanadium doped ZnO films prepared by dc reactive magnetron sputtering at different substrate temperatures

ZnO films doped with vanadium (ZnO:V) have been prepared by dc reactive magnetron sputtering technique at different substrate temperatures (RT–500 C). The effects of the substrate temperature on ZnO:V films properties have been studied. XRD measurements show that only ZnO polycrystalline structure has been obtained, no V2O5 or VO2 crystal phase can be observed. It has been found that the film prepared at low substrate temperature has a preferred orientation along the (002) direction. As the substrate temperature is increased, the (002) peak intensity decreases. When the substrate temperature reaches the 500 ºC, the film shows a random orientation. SEM measurements show a clear formation of the nano-grains in the sample surface when the substrate temperature is higher than 400 º C. The optical properties of the films have been studied by measuring the specular transmittance. The refractive index has been calculated by fitting the transmittance spectra using OJL model combined with harmonic oscillator

Sputtered highly ordered TiO2 nanorod arrays and their applications as the electrode in dye-sensitized solar cells

For the first time, the TiO2 nanorod arrays have been prepared on ITO substrates at room temperature by dc reactive magnetron sputtering technique. These TiO2 nanorods have a preferred orientation along the (220) direction and are perpendicular to the ITO substrate. Both the X-ray diffraction and Raman scattering measurements show that the highly ordered TiO2 nanorod arrays have an anatase crystal structure. The diameter of the nanorod varies from 30 nm to 100 nm and the nanorod length can be varied from several hundred nanometers to several micrometers depending on the deposition time. The TiO2 nanorod arrays with about 3 micrometers length have been used as an electrode for dye-sensitized solar cell (DSSC). Short-circuit photocurrent density, open-circuit voltage, fill factor and light-to-electricity conversion efficiency at 100 mW/cm2 light intensity are estimated to be 12.76 mA/cm2, 0.65 V, 0.63 and 5.25%, respectively, for the DSSC made of the TiO2 nanorods.SFRH/BSAB/862/2008, FC

Effect of the deposition rate on ITO thin films properties prepared by ion beam assisted deposition (IBAD) technique

Indium tin oxide (ITO) thin films have been deposited onto glass substrates at room temperature by ion beam assisted deposition technique at different deposition rates (0.1 -- 0.3 nm/s). The effects of the deposition rate on the structural, optical and electrical properties of the deposited films have been studied. The optical constants of the deposited films were calculated by fitting the transmittance spectra using the semi-quantum model. Considering the application for the electromagnetic wave shielding which needs a high IR reflectance, the optimising deposition rate is 0.2 nm/s. The films prepared at this deposition rate shows a relative high IR reflectance (60%), a good electrical conductivity (5 x 10-3 -cm), and a reasonable transmittance in the visible region (over 80%)

The effect of the ion beam energy on the properties of indium tin oxide thin films prepared by ion beam assisted deposition

Indium tin oxide (ITO) thin films have been deposited onto polycarbonate substrates by ion beam assisted deposition technique at room temperature. The structural, optical and electrical properties of the films have been characterized by X-ray diffraction, atomic force microscopy, optical transmittance, ellipsometric and Hall effect measurements. The effect of the ion beam energy on the properties of the films has been studied. The optical parameters have been obtained by fitting the ellipsometric spectra. It has been found that high quality ITO film (low electrical resistivity and high optical transmittance) can be obtained at low ion beam energy. In addition, the ITO film prepared at low ion beam energy gives a high reflectance in IR region which is useful for some electromagnetic wave shielding applications.Fundação Calouste Gulbenkia