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2.
TiO2 thin films were deposited on ITO/Glass substrates by the rf magnetron sputtering in this study. The electrochromic properties
of TiO2 films were investigated using cyclic voltammograms (CV), which were carried out on TiO2 films immersed in an electrolyte of 1 M LiClO4 in propylene carbonate (PC). As- deposited TiO2 thin film was amorphous, while the films post-annealed at 300~600°C contained crystallized anatase and rutile. With the increase
of the annealing temperature, the surface roughness of film increased from 1.232 nm to 1.950 nm. Experimental results reveal
that the processing parameters of TiO2 thin films will influence the electrochromic properties such as transmittance, ion-storage capacity, inserted charge, optical
density change, coloration efficiency and insertion coefficient. 相似文献
3.
Takeshi Miki Kaori Nishizawa Eiji Watanabe Hiroshi Taoda 《Research on Chemical Intermediates》2009,35(3):257-262
To obtain porous TiO2 film, the precursor sol was prepared by hydrolysis of Ti isopropoxide and then complexed with trehalose dihydrate. The porous
TiO2 film was fabricated by the dip-coating technique on glass substrates using this solution. The TiO2 film was calcined at 500 °C. The maximum thickness of the film from one-run dip-coating was ca. 740 nm. The film was composed
of nanosized particle and pores. The porosity of the TiO2 film was increased by addition of trehalose dihydrate to the sol. The porous TiO2 films were calcined at different temperatures. The effects of calcination temperature on the microstructure of the porous
TiO2 film were investigated. The porous film prepared from sol containing trehalose still kept the porous structure after calcination
at 950 °C. The phase transition temperature of the film from anatase to rutile was shifted from 650 to 700 °C by addition
of trehalose to the sol. 相似文献
4.
Pablo Romero‐Gomez Dr. Ana Borras Dr. Angel Barranco Prof. Dr. Juan P. Espinos Prof. Dr. Agustin R. Gonzalez‐Elipe 《Chemphyschem》2011,12(1):191-196
Herein, we study the photoactivity of anatase–rutile bilayer thin films consisting of an anatase overlayer of variable thickness from some tenths to some hundred nanometers deposited onto a rutile thin film. As references single anatase layers of equivalent thickness were deposited onto silicon. All the films were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. The photoactivity of the samples was assessed by following the evolution with the UV illumination time of both the wetting angle on the thin film surface and the decoloration of a dye in a water solution. While a similar efficiency is found for the first type of experiments irrespective of the anatase thickness, in the second type a maximum in the photoactivity is found for a thickness of the anatase layer of about 130 nm. This enhanced photoactivity in bilayer systems with a buried anatase–rutile heterojunction is related to the formation of different Schottky potential barriers in the anatase layer, depending on its thickness and the substrate (i.e. rutile or SiO2) where it is deposited. 相似文献
5.
Preparation of TiO2 Thin Film Photocatalysts by Dip Coating Using a Highly Viscous Solvent 总被引:6,自引:0,他引:6
TiO2 thin film photocatalysts coated onto soda lime glass were prepared by a dip coating process using a highly viscous solvent. The source of the TiO2 was tetraisopropyl orthotitanate, and -terpineol was used as the solvent. Two types of thin film preparation procedures based on dip coating (a sol-gel system and thermal decomposition system) were used to prepare the samples. TiO2 thin films were obtained after calcination at 450°C for 1 hour. The film thickness obtained with a single dipping was proportional to the viscosity of the dip coating solutions. The obtained thin films were transparent with a thickness of 1 m. The crystal form of the obtained photocatalyst films was anatase alone. The thin films were formed with aggregated nano-sized TiO2 single crystals (7–15 nm). The photocatalytic activity of the TiO2 thin films, as evaluated by the photooxidation of NO (1 ppm) in dry air, was as high as our previous TiO2 thin films prepared by the sol-gel method. 相似文献
6.
Yutaka Ohya Tsukasa Niwa Takayuki Ban Yasutaka Takahashi 《Journal of Sol-Gel Science and Technology》2005,33(3):323-326
Heterostack films of p-type NiO and n-type TiO2 semiconductors were deposited by a method of chemical solution deposition on a glass substrate having a sputtered ITO (In2O3 doped with Sn) electrode. Transparent films with total thickness of about 280 nm were obtained by heat treatments at 600°C. NiO reacted with TiO2 to give a NiTiO3 thin layer between them. The films exhibited a typical rectifying I-V behavior and this property was maintained at 300°C. The thickness of the NiTiO3 intermediate layer increase with the heating time at 600°C and leading to a decrease of the current density at low voltage. 相似文献
7.
采用对向靶磁控溅射法在不同气压和Ar/O2流量比条件下, 以氟化SnO2 (FTO)导电玻璃为基底制备了多晶TiO2薄膜. 台阶仪测量结果显示所制备TiO2薄膜的平均厚度约为200 nm. 随着溅射气压的升高, TiO2薄膜由锐钛矿与金红石混晶结构转变为纯锐钛矿结构. 分别采用场发射扫描电镜(FESEM)和原子力显微镜(AFM)分析了不同气压和Ar/O2流量比对TiO2薄膜表面形貌的影响, 结果显示TiO2薄膜的表面粗糙度随溅射总气压和Ar/O2流量比的增加而增大. 以初始浓度为100×10-6 (体积分数)的异丙醇(IPA)气体为目标物检测所制备TiO2薄膜的光催化性能, 并分析该气相光催化反应的机理, 在紫外照射条件下异丙醇先氧化为丙酮再被氧化为CO2.当总溅射气压为2.0 Pa、Ar/O2流量比为1:1时, 溅射所得TiO2薄膜具备最优光催化活性并可在IPA降解反应中保持较高的催化活性和稳定性. 相似文献
8.
Chen-lu Song Ju Wang Meng-long Zeng Jian-qiang Zhu Yong Liu Gang Xu Gao-rong Han 《Journal of Sol-Gel Science and Technology》2013,68(1):121-127
Fluorine-doped TiO2 thin films featuring columnar structure were prepared on fluorine-doped tin oxide (SnO2:F) substrate using a sol–gel method. The F doping ratios were varied in the range of 0–8 %. The effect of [F]/[Ti + F] ratio on the structural, morphological, optical, photocatalytic and low-emissivity properties has been investigated in detail. X-ray diffraction studies revealed that all the composited films are mainly composed of anatase TiO2 and rutile SnO2 without other phases. The prepared TiO2:F films possessed the columnar morphology with the single layer thickness ranging from 28 to 31 nm. The best photocatalytic activity was obtained for the films with 4 % F doping ratio which is mainly attributed to the highest crystallization and crystallite size. The transmission and hemispherical emissivity of the composite films could still reach approximately 70 % and 0.20, which match the requirements of the Chinese National Standard (GB/T18915.2-2002), promoting the films for the practical applications. 相似文献
9.
Y. X. Guo C. W. Zou Y. F. Liu Y. Q. Xu X. L. Wang J. Y. Yu Z. Y. Yang F. Zhang R. Zhou 《Journal of Sol-Gel Science and Technology》2014,69(1):40-46
The Ba0.6Sr0.4TiO3 (BST60) thin films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates by a sol–gel method. The thickness of CeO2, serving as a buffer layer, was varied from 0 to 75 nm, in order to optimize the dielectric tunable property. X-ray patterns analysis indicates that all the thin films exhibit good crystalline quality with a pure perovskite phase and insertion of the CeO2 buffer layer does not change the crystal structure of BST60. Dielectric properties of the thin films were investigated as a function of both temperature and direct current electric field. The results show that dielectric constant and loss are modified by insertion of the CeO2 buffer layer. The BST60 thin films with 25 nm thickness CeO2 buffer layer have the highest figure of merit, low dielectric loss, and suitable dielectric constant, which render them attractive for the tunable microwave device applications. 相似文献
10.
J. Nayak K. Prabakar J. W. Park Heeje Kim 《Journal of Sol-Gel Science and Technology》2013,66(3):378-386
Rutile TiO2 nanocrystals having rectangular faces were directly deposited on fluorine-doped tin oxide coated glass substrates. Using polyethylene glycol-400 as the surfactant, we succeeded in growing a porous rutile layer having maximum thickness of 4.8 μm and containing nanocrystals with lateral dimensions of at least 30 nm. We observed that polyethylene glycol not only controlled the sizes of the nanocrystals but also enhanced the rate of deposition. The nanocrystals had rutile structure and the film was strongly textured with preferential orientation along {002} direction. The dye adsorption properties of the nanocrystalline films depended on their microscopic surface areas which were determined by the sizes of the nanocrystals. A dye-sensitized solar cell, fabricated with a 4.8 μm thick nanocrystalline rutile thin film photoanode, exhibited a light-to-electricity conversion efficiency of 5.02 % under 1.0 sun illumination. The internal resistance, interface capacitance and electron lifetime of dye sensitized solar cell were estimated by electrochemical impedance spectroscopy and an electron lifetime of 0.19 s was recorded. 相似文献
11.
Won Young Jung Seung Hee Baek Seong Soo Park Gun-Dae Lee Euh Duck Jeong Hyun Gyu Kim Seong-Soo Hong 《Reaction Kinetics and Catalysis Letters》2007,91(2):233-240
The nanosized titania and TiO2/SiO2 particles were prepared by the microwave-hydrothermal method. The effect of physical properties TTIP/TEOS ratio and calcination
temperature has been investigated. The major phase of the pure TiO2 particle is of the anatase structure, and a rutile peak was observed above 800°C. In TiO2/SiO2 particles, however, no significant rutile phase was observed, although the calcination temperature was 900°C. No peaks for
the silica crystal phase were observed at either silica/titania ratio. The crystallite size of TiO2/SiO2 particles decreases as compared to pure TiO2 at high calcination temperatures. The TiO2/SiO2 particles show higher activity on the photocatalytic decomposition of orange II as compared to pure TiO2 particles. 相似文献
12.
M. Chandra Sekhar N. Nanda Kumar Reddy B. Venkata Rao G. Mohan Rao S. Uthanna 《Surface and interface analysis : SIA》2014,46(7):465-471
Titanium dioxide (TiO2) thin films were deposited onto p‐Si substrates held at room temperature by reactive Direct Current (DC) magnetron sputtering at various sputter powers in the range 80–200 W. The as‐deposited TiO2 films were annealed at a temperature of 1023 K. The post‐annealed films were characterized for crystallographic structure, chemical binding configuration, surface morphology and optical absorption. The electrical and dielectric properties of Al/TiO2/p‐Si structure were determined from the capacitance–voltage and current–voltage characteristics. X‐ray diffraction studies confirmed that the as‐deposited films were amorphous in nature. After post‐annealing at 1023 K, the films formed at lower powers exhibited anatase phase, where as those deposited at sputter powers > 160 W showed the mixed anatase and rutile phases of TiO2. The surface morphology of the films varied significantly with the increase of sputter power. The electrical and dielectric properties on the air‐annealed Al/TiO2/p‐Si structures were studied. The effect of sputter power on the electrical and dielectric characteristics of the structure of Al/TiO2/p‐Si (metal‐insulator‐semiconductor) was systematically investigated. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
13.
Flat and highly (111) oriented gold and silver films were prepared by physical vapour deposition (PVD) using optimized deposition parameters. On these films, which were characterized with atomic force microscopy (AFM), scanning tunneling microscopy (STM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), titanium dioxide films were deposited by electron beam evaporation and dip coating. Dip coating from titanium tetraisopropoxide solutions resulted in films with different morphology and coverage depending on the alkoxide concentration (0.009 mol/L – 0.60 mol/L) and the post-treatment. Scanning electron microscopy (SEM) and AFM revealed that the deposited TiO2 consists of amorphous, highly porous islands when the applied alkoxide concentration is high (0.05 mol/L – 0.6 mol/L). At higher temperatures these amorphous TiO2 islands sintered significantly and crystallized to anatase. In contrast, transparent TiO2 films were obtained from low concentrated alkoxide solutions (< 0.01 mol/L) which covered the whole substrate, similar to electron beam evaporated thin films. Sputter profiles with ion scattering spectroscopy (ISS) indicated that the film thickness is in the range of 2 nm when alkoxide solutions with a concentration of 9 mmol/L are used. The deposition of TiO2 by electron beam evaporation normally resulted in significantly reduced TiO2 films, completely oxidized ones were obtained when deposition was performed at elevated oxygen partial pressures (p(O2) > 2 × 10–5 mbar). 相似文献
14.
采用溶胶-凝胶法分别在K9玻璃、单晶硅和石英玻璃基底上制备了纳米TiO2和SiO2薄膜。利用SEM、UV-Vis及反射式椭圆偏振光谱仪对薄膜的微观结构及光学特性进行了表征和分析。结果表明:3种基底中, 单晶硅基底上TiO2和SiO2薄膜折射率最大;在非晶态K9玻璃和石英玻璃基底上TiO2薄膜折射率和透光率差异较大;SiO2薄膜在非晶态基底上折射率、透光率相近;3种基底上薄膜的折射率和消光系数都有随波长增大而减小的趋势, 同时Cauchy模型能较好的描述单晶硅基底上两种薄膜在400~800 nm波段的光学性能。 相似文献
15.
采用溶胶-凝胶法分别在K9玻璃、单晶硅和石英玻璃基底上制备了纳米TiO2和SiO2薄膜。利用SEM、UV-Vis及反射式椭圆偏振光谱仪对薄膜的微观结构及光学特性进行了表征和分析。结果表明:3种基底中, 单晶硅基底上TiO2和SiO2薄膜折射率最大;在非晶态K9玻璃和石英玻璃基底上TiO2薄膜折射率和透光率差异较大;SiO2薄膜在非晶态基底上折射率、透光率相近;3种基底上薄膜的折射率和消光系数都有随波长增大而减小的趋势, 同时Cauchy模型能较好的描述单晶硅基底上两种薄膜在400~800 nm波段的光学性能。 相似文献
16.
The effects of adding dispersed powders of various forms of titanium(IV) dioxide on the photodegradation of polyethylene have been examined from the following points of view: effect of crystal form, concentration of pigment, transition metal ion, dopant concentration, calcination temperature of pigment, and pigment coating.The rate of photodegradation of polyethylene is reduced by adding certain grades of TiO2 such as coated TiO2 particles or TiO2 doped with small percentages of Cr or Mn ions. The rate is increased on adding TiO2 doped with V and especially Mo or W ions. The anatase form of TiO2 is more photoactive than the rutile form, and the effect of increasing the calcination temperature of the pigment is to reduce photoactivity by boosting the rutile fraction. The concentration dependences of the degradation rates are complex, but can be directly related to the percentage of anatase achieved after calcination. Even the most aggressive of the metal-doped pigments are less photoactive than the Degussa P25 material, containing both rutile and anatase. 相似文献
17.
Isaías Juárez-Ramírez Edgar Moctezuma Leticia M. Torres-Martínez Christian Gómez-Solís 《Research on Chemical Intermediates》2013,39(4):1523-1531
The deposition of TiO2 nanoparticles on SiC was carried out by mechanical milling under different conditions. SiC–TiO2 samples were used as photocatalysts for the degradation of organic dyes such as methylene blue and rhodamine B. A short time deposition of TiO2 nanoparticles was observed during mechanical milling (2 min at 200 rpm) to cover the SiC particles. The presence of SiC and TiO2 (anatase and rutile) was confirmed by means of X-ray diffraction after thermal treatment at 450 °C. The deposition of TiO2 on SiC was corroborated by scanning electron microscopy analysis; the thickness of the thin layer of TiO2 deposited on SiC increases as the proportion of TiO2 increases. The energy band gap values obtained for these compounds were around 3.0 eV. SiC–TiO2 photocatalysts prepared by mechanical milling exhibited better activity under UV-light irradiation for the degradation of methylene blue and rhodamine B than commercial TiO2 powder (titania P25). 相似文献
18.
Chun Wang Jürgen Meinhardt Peer Löbmann 《Journal of Sol-Gel Science and Technology》2010,53(2):148-153
TiO2 and Nb-doped TiO2 films were prepared by sol–gel processing, their microstructure was adjusted by varying the number of subsequent coating-firing
cycles that resulted in final total film thickness of ~100 nm. When only few subsequent coatings are stacked (large single
layer thickness) granular polycrystalline microstructures are observed. Doping with Nb reduces the crystallite size compared
to the respective pure anatase films. When the single layer thickness is reduced, the film growth is successively dominated
by the nucleation of subsequent films on the underlying crystalline material resulting in a columnar dense film structure.
The multilayer architecture of such films can be demonstrated by defocus TEM imaging even if crystalline columns exceed single
film boundaries. Results indicate that Nb is homogeneously incorporated into the anatase lattice by substitution of Ti, nevertheless
the electric conductivity after H2 post annealing is significantly lower than reported for analogous films prepared by magneton sputtering or pulsed laser deposition. 相似文献
19.
The photocatalytic activity of TiO2 nanofibers immobilized on quartz substrates was investigated by evaluating the decomposition of organic pollutants. TiO2 nanofibers were synthesized by electrospinning the Ti-precursor/polymer mixture solution, followed by hot-pressing for enhancing
the adhesion of TiO2-nanofiber films to the substrates. TiO2 started to crystalize in the anatase form at 500 °C and reached the optimal photocatalytic anatase/rutile phase ratio of
70:30 at a calcination temperature of 600 °C. The TiO2-nanofiber film was demonstrated to be an efficient photocatalyst by ranitidine decomposition under UV illumination and was
proven to have a comparable photocatalytic activity with the well-known Degussa P25 nanoparticulate photocatalyst and excellent
recyclability during 10 cycles of photocatalytic operation, indicating no loss of TiO2 nanofibers during photocatalytic operations. 相似文献
20.
Lukasz Szymanski Praveen Surolia Owen Byrne K. Ravindranathan Thampi Cosima Stubenrauch 《Colloid and polymer science》2013,291(4):805-815
The synthesis of porous “sponge-like” TiO2 via a polymer gel coating technique is presented. The experimental procedure involves the preparation of a gelled polymerizable microemulsion. The polymerization of the latter leads to porous poly-N-isopropylacrylamide which forms a hydrogel in the presence of water. Via solvent exchange, a suitable TiO2 precursor is infiltrated into this structure after which its in situ hydrolysis is triggered to form porous amorphous TiO2. The subsequent calcination step allows the removal of the polymer template and the transformation of amorphous TiO2 into porous, crystalline anatase with domain sizes ranging from 200 to 250 nm. As a means of verification and proof of concept, this material is tested as light-scattering layer in dye-sensitized solar cells (DSSC), and it is found that the resulting solar cell performance is comparable to commercially available TiO2. However, an increased tendency to form rutile during DSSC fabrication was noticed when compared to commercial TiO2. As there is a large potential for optimizing the synthesis, the proposed procedure is a promising route towards porous TiO2 that performs significantly better as scattering layer in light-harvesting and optical devices. 相似文献