Time dependent facile hydrothermal synthesis of tio2 nanorods andtheir photoelectrochemical applications 2157 7439 S (original) (raw)
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Photoelectrochemical solar cell based on surfactant mediated rutile TiO2 nanorods
Journal of Materials Science: Materials in Electronics, 2015
Rutile titanium dioxide nanorods have been synthesized by a simple and cost-effective hydrothermal deposition method onto the conducting glass substrates. In order to study the effect of surfactants on the growth of TiO 2 , different surfactants like ethylenediaminetetraacetic acid, polyvinylpyrrolidone, cetyltrimethylammonium bromide and sodium dodecyl sulphate (SDS) are used. These films are characterized for their morphological, structural, compositional, optical and electrochemical properties using field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence and electrochemical impedance spectroscopy techniques. FE-SEM images showed the formation of densely packed nanorods for SDS mediated TiO 2 . XRD patterns show the formation of polycrystalline TiO 2 with the tetragonal crystal structure possessing rutile phase. The chemical composition and valence states of the constituent elements were analysed by XPS. The films were photoelectrochemically active with the maximum current density of 378 lA/cm 2 with enhanced photovoltage of 615 mV for the sample prepared with SDS surfactant.
Growth, Single-Crystalline Rutile TiO2 Nanorod Thin Film By Hydrothermal Technique
Journal of Kufa Physics, 2018
Hydrothermal technique growth single-crystalline rutile TiO2 nanorod thin films A facile, hydrothermal technique was developed to growth, singlecrystalline rutile TiO2 nanorod thin films on transparent conductive fluorine-doped tin oxide (FTO) substrates. In this study, the deferent periods(6, 9, 12, 15, and 18 hour) were selective with constant temperature at 160 o C to growth this films and growth in deferent temperature (130, 150,170,190, and 210 o C) with constant period of deposition at 6h. SEM image showed all the films were nanorodand the EDX measurement was given the portion of element that contribution in rutile TiO2 nanorod thin films. The diameter, length, and density of the nanorods could be varied by changingthe growth parameters. The XRD to determine the structure properties, and optical properties were measured of these rutile TiO2 nanorod thin films and obtained the absorbance and energy gap. http://dx.doi.org/10.31257/2018/JKP/100206 بيكرت مويناتيتلا ذيسكوأ يئان...
Digest Journal of Nanomaterials and Biostructures
Titanium butoxide (Ti(OBu)4) precursor was used to prepare titanium dioxide (TiO2) nanorods as a photoanode by hydrothermal method directly on FTO glass with different hydrochloric acid (HCl) – water (H2O) ratio (12.5-7.5, 10-10, 7.5-12.5 and 5-15) ml and etching times (24, 48, and 72)h. The (XRD) results show good crystallinity of TiO2 with rutile phase and preferred orientations (101) and (002) for all samples. The grain size of the TiO2 nanorods increases with decrease the HCl concentration. The (FESEM) images show that an increase in HCl concentration leads to an increase in the rod diameter of the TiO2 NRs and a decrease in their length. The optimum efficiency (η) of DSSC based on TiO2 NRs was 3.255% at sample ET, where the preparation condition (7.5 ml HCl + 12.5 H2O) with a 48 h etching time.
Superlattices and Microstructures, 2018
The vertically aligned TiO 2 nanorods were deposited on fluorine-doped tin oxide glass substrates by using the hydrothermal method at a different reaction temperature from 150-180. The effects of reaction temperature on structural, morphological and optical properties of deposited TiO 2 films have been investigated systematically. Further, the TiO 2 films were used as a photoanode for efficient dye-sensitized solar cell (DSSC) application. The XRD patterns show the formation of the rutile phase with the tetragonal crystal structure. FESEM images revealed the increase in length and diameter of TiO 2 nanorods with respect to the reaction temperature. Current density-voltage characteristics of DSSC showed the correlation between the photoconversion efficiency and reaction temperature. The maximum photoelectric conversion efficiency reached 1.79 % along with short-circuit current density of 2.90 mA/cm 2 and opencircuit potential of 765 mV was observed for TiO 2 film deposited at 180 .
Titanium dioxide (TiO 2) is a versatile and inexpensive material for extended applicability in several scientific and technological fields including photo-catalysis for industrial waste treatment, energy harvesting, and hydrogen production. In this work, we report the synthesis of TiO 2 thin film using hydrothermal method and investigations on the influence of reaction time and annealing temperature on growth mechanism of the TiO 2 nanorods. The synthesized TiO 2 films were studied by using UV-visible spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscope and energy-dispersive X-ray spectroscopy (EDS). The XRD and Raman measurements revealed the formation of defect free and pure tetragonal TiO 2 rutile phase. The TiO 2 thin films show absorption band edge at around 420 nm in the UVvisible spectrum and exhibit direct band gap value of 2.9 eV. The TiO 2 nanorods are demonstrated to grow randomly on the FTO substrate with changing reaction times but grow uniformly in a flower-like pattern with increasing annealing temperature. Investigation of the field emission properties of TiO 2 thin films (tested as field-emitter array) estimates the turn-on and threshold field at 4.06 and 7.06 V/µm at 10 and 100 µA/cm 2 , respectively.
Effect of seed layer on growth of rutile TiO2 nanorods
Journal of Physics: Conference Series
For achieving the high quality of titanium dioxide (TiO 2) nanorods, herein, we present a synthesis of rutile TiO 2 nanorods on a transparent conductive fluorine-doped tin oxide (FTO) glass substratewith seed layer by a two-step method. TiO 2 thin films were first precoated by spin coating and annealing, followed by the growth of TiO 2 nanorods with a hydrothermal method. The crystallographic nanostructures and properties of the nanorods were investigated. XRD results demonstrate that seed layer was tetragonal anatase TiO 2 structure while nanorods had tetragonal rutile TiO 2 structure. Since the hydrothermal technique was conducted in medium acid, structure of nanorods was induced to form in rutile phase. The major characteristic orientation of nanorods on the seed layers was (002) and minor in (101) planes. FE-SEM results show that seed layer enhances the process to achieve vertical-aligned orientation of the TiO 2 nanorods, which contribute to develop electron transport rate and could pay an important role inelectron transport layer in high-performance Perovskite solar cell.
Nanocrystalline thin films of TiO 2 were prepared on glass substrates from an aqueous solution of TiCl 3 and NH 4 OH at room temperature using the simple and cost-effective chemical bath deposition (CBD) method. The influence of deposition time on structural, morphological and optical properties was systematically investigated. TiO 2 transition from a mixed anatase-rutile phase to a pure rutile phase was revealed by low-angle XRD and Raman spectroscopy. Rutile phase formation was confirmed by FTIR spectroscopy. Scanning electron micrographs revealed that the multigrain structure of as-deposited TiO 2 thin films was completely converted into semi-spherical nanoparticles. Optical studies showed that rutile thin films had a high absorption coefficient and a direct bandgap. The optical bandgap decreased slightly (3.29-3.07 eV) with increasing deposition time. The ease of deposition of rutile thin films at low temperature is useful for the fabrication of extremely thin absorber (ETA) solar cells, dye-sensitized solar cells, and gas sensors.
Growth of rutile TiO2 nanorods on TiO2 seed layer prepared using facile low cost chemical methods
Materials Letters, 2014
Dense rutile TiO 2 nanorods were grown on an anatase TiO 2 seed layer by a wet-chemical approach in which the nuclei layer was prepared by the chemical spray pyrolysis technique. Structural, morphological, and optical properties of prepared samples were investigated using X-ray diffraction (XRD), micro-Raman, scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-vis spectroscopy, and fluorescence spectroscopy. From XRD, a clear authentication that, the preferentially oriented crystallographic planes indicate that the rutile TiO 2 nanorods are standing randomly along the normal to the substrate surface. Anatase TiO 2 seed layer and rutile nanorods structural phases are clearly confirmed by micro-Raman measurement. SEM and AFM studies reveal that the TiO 2 seed layer consists of high density nanoparticles with the thickness of 0.15 μm and the height of the as-grown nanorods is $ 0.6 μm. The band gap energy of the anatase TiO 2 seed layer and rutile as-grown nanorods is calculated using UVvis absorption spectra and the band gap values of seed layer and nanorods are 3.21 eV and 2.95 eV respectively. The crystal defects of prepared films are measured using photoluminescence spectra.
Journal of Sol-Gel Science and Technology
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Journal of the Iranian Chemical Society, 2019
In this study, using the optimum annealing temperature and time for hydrothermally grown TiO 2 nanorods, photooxidation of water at different pH values of the electrolyte solution is investigated. The composition, crystallinity and topographic studies of films, sintered at different temperatures of 200-500 °C for 2 h and annealed for 1-4 h at 400 °C, were evaluated by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and field emission scanning electron microscopy. The sintering at high temperature and for longer time demonstrates an increase in crystallinity, but at the same time agglomeration of nanorods for prolonged heating and at high temperature leads to cracking at the surface of the films. Further, UV-Vis spectroscopic studies revealed prolonged heating and high-temperature sintering resulted in a red shift in light absorption edge of the films. The chronoamperometric measurement results under regular interrupted chopping revealed that the sample annealed at 400 °C for 2 h gives the best photoelectrochemical response with photocurrent density of 522 µA cm − 2 using 0.5M NaOH. The chronoamperometric response under different pH values of 13.7, 7.2 and 2.5 proved that TiO 2 gives the best response under a basic pH of 13.7 and the least under acidic media. The electrochemical impedance studies provided an insight into the charge transfer mechanism under dark and illumination with R ct value of 1188.8 Ω under dark and 164.5 Ω under light conditions for the film annealed at 400 °C for 2 h.