Photoconducting TiO2 prepared by spray pyrolysis using TiCl4

Zhang, S.; Zhu, Yanji; Brodie, Douglas

doi:10.1016/0040-6090(92)90292-j

Cited by 78 publications

(20 citation statements)

References 17 publications

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“…E g varies for the anatase phase between 3.2 eV [14], 3.46 eV [21], 3.5±3.7 eV [22] and 3.98 eV [23] depending on the preparation conditions and measurement techniques. For example, PC measurements on por-TiO 2 give usually E g 3.2 eV [14] while photoelectrochemical investigations on thin anatase electrodes give 3.15±3.3 and 3.5±3.7 eV for indirect and direct bandgap analysis, respectively [24].…”

Section: Resultsmentioning

confidence: 99%

Porous TiO2: Electron Transport and Application to Dye Sensitized Injection Solar Cells

Dittrich

2000

phys. stat. sol. (a)

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Porous TiO 2 (anatase, rutile) belongs to the class of materials with very low drift mobility of electrons (10 ± ±4 ±10 ± ±7 cm/Vs). The drift mobility is limited by traps being responsible for the slow interparticle charge transfer. The deep traps are generated at the TiO 2 surface in oxygen deficient atmosphere and should be avoided in dye sensitized injection solar cells since they increase the saturation current. Another group of defects is related to disorder in the bulk TiO 2 . The disorder is much stronger for anatase than for rutile. The respective optical bandgap of the undisturbed anatase is 3.45 eV. The disorder related defects do not limit the efficiency of the dye sensitized injection solar cell. The current dependent barrier height has been shown to be important as a limiting factor for the energy conversion efficiency in dye sensitized injection solar cells at moderate light intensity.Introduction Nanoporous semiconductors belong to the class of materials with very low drift mobilities (m) of charge carriers. For example, m is in the order of 10 ± ±4 ±10 ± ±1 and 10 ± ±4 ±10 ± ±6 cm 2 /Vs for electrons in nanoporous Si [1] and porous TiO 2 [2], respectively, what is lower by four to six orders of magnitude than m for the single crystalline Si and TiO 2 [3], an overview of electron Hall mobilities is given in [4]. The main reasons for the strong decrease of m are the complex network of a nanoporous structure, see e.g.[5] and the huge internal surface area of a porous semiconductor, see e.g. [6] which may lead to hopping transport on a fractal [7] or trap limited transport [8]. However, the microscopic picture of the charge transport is more complicated, especially in the presence of injected carriers of charge.The electronic transport in porous semiconductors is extremely sensitive to adsorbed molecules which change the distribution of electronic states. This bears a large potential for applications in sensors, especially for porous metal oxides, see e.g. [9,10]. The electronic states below the bandgap are not well investigated in porous metal oxides and their nature is not well understood up to now. Metal oxides are very sensitive to nonstoichiometry. A deficit of oxygen causes n-type doping (high temperature (T), low partial pressure of oxygen (p O 2 )) while additional incorporation of oxygen into the metal oxide leads to p-type doping, see e.g. [11]. TiO 2 is of n-type [12]. By using reduction and oxidation reactions one can reversibly cycle or refresh the electronic properties of metal oxides.TiO 2 is a wide bandgap semiconductor (E g 3.06 eV for the rutile phase [13]) and it can be easily produced as a nanocrystalline powder. (TiO 2 nanoparticles are widely used, for example, in white paint.) These two properties make TiO 2 nanoparticles quite interesting for application in dye sensitized injection solar cells, the so-called ªGra È tzelcellsº [14]. The idea of the injection solar cell is the separation in space of the steps of

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Section: Resultsmentioning

confidence: 99%

Porous TiO2: Electron Transport and Application to Dye Sensitized Injection Solar Cells

Dittrich

2000

phys. stat. sol. (a)

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“…In general, films are prepared on substrates by sputtering, sol-gel methods, etc. [6][7][8][9][10][11]. Although such conventional methods are welldeveloped techniques, several problems associated with these still remain.…”

Section: Introductionmentioning

confidence: 98%

Hydrothermal synthesis of anatase-type TiO2 films on Ti and Ti–Nb substrates

Ueda

Uchibayashi²,

Otsuka‐Yao‐Matsuo³

et al. 2008

Journal of Alloys and Compounds

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“…7 Hydrolysis of a variety of titanium alkoxide precursors has been used to produce finely dispersed high-purity TiO 2 powders. For preparation of thin films of TiO 2 , several techniques have been reported, for example dc reactive magnetron sputtering, 8 spray pyrolysis, 9 chemical vapor deposition, 10 sol-gel techniques, 11 ultrasonic aerosol-assisted chemical vapor deposition (UAACVD), 12 and electron beam evaporation. 13 Among these UAACVD is a highly effective and simple means of producing nanosized powders and conformal thin films on variety of substrates, including ceramics.…”

Section: Introductionmentioning

confidence: 99%

Ultrasound-Assisted Synthesis of Titania Nanoparticles, Characterization of Their Thin Films, and Activity in Photooxidation of β-Naphthol

Hurain

Habib

Hussain

et al. 2015

Journal of Elec Materi

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Nanosized titania (TiO 2 ) films and powders were prepared from titanium isopropoxide by ultrasonication then ultrasonic aerosol-assisted chemical vapor deposition (UAACVD). X-ray diffraction (XRD), used to study the crystal structure, phase, and crystallite size of TiO 2 samples annealed at 500°C, revealed anatase was the main crystalline phase. Scanning electron microscopy and atomic force microscopy revealed the quasi-spherical morphology of the TiO 2 nanoparticles; average size distribution was in the range 20-35 nm. Ultraviolet-visible spectroscopy was used to evaluate the photocatalytic activity of the anatase TiO 2 , on the basis of efficiency of degradation of bnaphthol. Pure TiO 2 nanoparticles synthesized by use of sonication-UAACVD then calcination at 500°C enabled effective photodegradation under UV light. This method of synthesis of TiO 2 is superior to the reflux-UAACVD method with titanium isopropoxide as precursor.

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Photoconducting TiO2 prepared by spray pyrolysis using TiCl4

Cited by 78 publications

References 17 publications

Porous TiO2: Electron Transport and Application to Dye Sensitized Injection Solar Cells

Porous TiO2: Electron Transport and Application to Dye Sensitized Injection Solar Cells

Hydrothermal synthesis of anatase-type TiO2 films on Ti and Ti–Nb substrates

Ultrasound-Assisted Synthesis of Titania Nanoparticles, Characterization of Their Thin Films, and Activity in Photooxidation of β-Naphthol

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