Photochromic properties of WO3 and WO3:X (X=Ti, Nb, Ta and Zr) thin films

Avellaneda, César O.; Bulhões, L.O.S.

doi:10.1016/j.ssi.2003.08.023

Cited by 116 publications

(37 citation statements)

References 11 publications

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“…[5] The properties of tungsten oxide thin films are strongly dependent on the deposition technique and choice of precursor. Sol-gel, [6] sputtering [7] and spray pyrolysis [8] methods have been reported, but chemical vapour deposition (CVD) offers the greatest potential for large-scale coatings. Precursors for CVD include various classes of organometallics, e.g.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric pressure chemical vapour deposition of WO₃ thin films from a volatile fluorinated tungsten oxo‐alkoxide precursor, W(O)(OCH₂CF₃)₄

Molloy¹,

Williams²

2008

Applied Organom Chemis

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Section: Introductionmentioning

confidence: 99%

Atmospheric pressure chemical vapour deposition of WO₃ thin films from a volatile fluorinated tungsten oxo‐alkoxide precursor, W(O)(OCH₂CF₃)₄

Molloy¹,

Williams²

2008

Applied Organom Chemis

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“…One of the most interesting metal oxides is tungsten oxide, W O 3 , which has been investigated extensively because of its distinctive applications such as electrochromic [3,4,5,6,7], photochromic [8], gas sensor [9,10,11], photo-catalyst [12], and photoluminescence properties [13]. Many properties of tungsten oxide are related to its surface structure (e.g.…”

mentioning

confidence: 99%

Conformal Curves on theWO3Surface

2008

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We have studied the iso-height lines on the WO3 surface as a physical candidate for conformally invariant curves. We have shown that these lines are conformally invariant with the same statistics of domain walls in the critical Ising model. They belong to the family of conformal invariant curves called Schramm-Loewner evolution (or SLEκ), with diffusivity of κ ∼ 3. This can be regarded as the first experimental observation of SLE curves. We have also argued that Ballistic Deposition (BD) can serve as a growth model giving rise to contours with similar statistics at large scales. The study of random surfaces, especially their statistical properties as well as growth and evolution dynamics, has been growing over the last two decades. They describe many important problems of real surfaces appearing in condensed matter physics such as deposited metal. In addition, this kind of problems is closely related to other problems in physics such as fractured surfaces, string theory, phase transitions in two dimensions etc [1,2]. The aim of this paper is to show that conformally invariant curves appear on the iso-height contours of deposited films of W O 3 . This is the first observation of SLE in real physical system. We believe that the same result may be observed for other surfaces.Metal oxides are a large family of materials possessing various interesting properties. One of the most interesting metal oxides is tungsten oxide, W O 3 , which has been investigated extensively because of its distinctive applications such as electrochromic [3,4,5,6,7], photochromic [8], gas sensor [9, 10, 11], photo-catalyst [12], and photoluminescence properties [13]. Many properties of tungsten oxide are related to its surface structure (e.g. porosity, surface-to-volume ratio) and surface morphology and statistics such as grain size and height distribution of the sample. These properties are also affected by conditions during the growth process such as deposition method. One can change the statistics of the growth surface by imposing external parameters such as annealing temperature which can even cause phase transition in the sample [14].On the other hand, calculation of various geometrical exponents of a random Gaussian surface is of interest to theoretical physics. From this point of view, we want to study the morphology and geometrical statistics of experimental grown surfaces of W O 3 . We consider contour lines (the nonintersecting iso-hight lines) on the W O 3 samples and show that they are conformally invariant. This analysis when applied to the contour lines of the ballistic disposition (BD) model shows similar conformally invariant surface in large scales. The scaling behavior of contour lines in the growth models are widely investigated. For example in [15] the authors derived some of the universal exponents of contour lines, especially their fractal dimension D 0 and its relation to the roughness exponent α. Moreover, Schramm and Sheffield recently showed that the contour lines in a two-dimensional discrete Gaussian free field a...

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“…However, WO 3 has a large band gap of 2.8 eV where it can only absorb < 450 nm wavelength in the solar spectrum. In order to reduce the band gap, WO 3 was synthesized via different methods [18][19][20][21]. The narrow band gap of 2.20 -2.80 eV helps in absorption of ultraviolet region and blue region of visible light in solar spectrum [22][23][24][25].…”

Section: Ng Et Al: Fabrication and Characterization Of Fe-doped Tungsmentioning

confidence: 99%

FABRICATION AND CHARACTERIZATION OF Fe-DOPED TUNGSTEN TRIOXIDE PHOTOELECTRODES IN AQUEOUS MEDIUM USING TUNGSTIC ACID AND FERROCENE AS STARTING MATERIALS

Hang

Jaafar

Minggu³

et al. 2016

MJAS

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Different compositions of Fe-doped tungsten trioxide thin films were synthesized on fluorine-doped tin oxide (FTO) glass substrate by sol-gel method, with ferrocene and tungstic acid as starting materials. The synthesized thin films was characterized with X-ray diffraction (XRD), scanning electron microscope (SEM), UV/Vis spectrophotometer and photoelectrochemical (PEC) analysis. The results show that the surface morphology of the thin films became rough and the grain size increased along with the concentration of Fe. Monoclinic structure of tungsten trioxide was obtained for all doped and undoped WO 3 and red-shift can be observed from UV-vis spectrum. Band gap reduced from 2.74 eV of undoped WO 3 thin films to 2.60 eV of 20 % Fe-doped WO 3 thin films. Photoactivities of all Fe-doped WO 3 are higher than undoped thin films. The highest photoactivities contributed by 5 % Fe-doped WO 3 films with photocurrent densities measured was 0.148 mA/cm 2 , which is 3 times higher compared to undoped WO 3 .Keywords: Fe-doped WO 3 , direct water splitting, photoelectrochemical cell, photoanode Abstrak Filem nipis tungsten trioksida terdop Fe berbagai komposisi telah disediakan di atas kaca substrat FTO (fluorine-doped tin oxide) dengan kaedah sol-gel, dengan menggunakan ferosin dan asid tingstik sebagai bahan pemula. Filem nipis yang terhasil kemudiannya dicirikan dengan pembelauan sinar X (XRD), mikroskopi elektron pengimbasan (SEM), UV/Vis spektrofotometer dan analisis fotoelektrokimia. Keputusan menunjukkan bahawa morfologi permukaan filem nipis menjadi kasar dan saiz butiran bertambah dengan penambahan kepekatan Fe. Tungsten trioksida yang berstruktur monoklinik telah dihasilkan dan anjakan merah telah diperhatikan di dalam spectrum UV-vis. Jurang tenaga telah berkurang dari 2.74 eV (WO 3 tulen) kepada 2.60 eV (20 % Fe-dop WO 3 ). Fotoaktiviti WO 3 terdop Fe adalah lebih tinggi berbanding WO 3 tulen. Fotoaktiviti yang tertinggi dicatatkan oleh filem 5 % WO 3 terdop Fe dengan ketumpatan fotoarus 0.148 mA/cm 2 . Ia adalah 3 kali ganda lebih tinggi berbanding WO 3 tulen.Kata kunci: Fe-dop WO 3 , pembelahan air secara langsung, sel fotoelektrokimia, fotoanod

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Photochromic properties of WO3 and WO3:X (X=Ti, Nb, Ta and Zr) thin films

Cited by 116 publications

References 11 publications

Atmospheric pressure chemical vapour deposition of WO₃ thin films from a volatile fluorinated tungsten oxo‐alkoxide precursor, W(O)(OCH₂CF₃)₄

Atmospheric pressure chemical vapour deposition of WO₃ thin films from a volatile fluorinated tungsten oxo‐alkoxide precursor, W(O)(OCH₂CF₃)₄

Conformal Curves on theWO3Surface

FABRICATION AND CHARACTERIZATION OF Fe-DOPED TUNGSTEN TRIOXIDE PHOTOELECTRODES IN AQUEOUS MEDIUM USING TUNGSTIC ACID AND FERROCENE AS STARTING MATERIALS

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Photochromic properties of WO3 and WO3:X (X=Ti, Nb, Ta and Zr) thin films

Cited by 116 publications

References 11 publications

Atmospheric pressure chemical vapour deposition of WO3 thin films from a volatile fluorinated tungsten oxo‐alkoxide precursor, W(O)(OCH2CF3)4

Atmospheric pressure chemical vapour deposition of WO3 thin films from a volatile fluorinated tungsten oxo‐alkoxide precursor, W(O)(OCH2CF3)4

Conformal Curves on theWO3Surface

FABRICATION AND CHARACTERIZATION OF Fe-DOPED TUNGSTEN TRIOXIDE PHOTOELECTRODES IN AQUEOUS MEDIUM USING TUNGSTIC ACID AND FERROCENE AS STARTING MATERIALS

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Atmospheric pressure chemical vapour deposition of WO₃ thin films from a volatile fluorinated tungsten oxo‐alkoxide precursor, W(O)(OCH₂CF₃)₄

Atmospheric pressure chemical vapour deposition of WO₃ thin films from a volatile fluorinated tungsten oxo‐alkoxide precursor, W(O)(OCH₂CF₃)₄