Characterization of nanocrystalline anatase TiO2 thin films

Abstract

Nanoporous thin films were deposited onto glass substrates by painting with a solution of nanocrystalline anatase TiO(2) particles (with a size of either 6 nm or 16 nm) suspended in an organic solvent. Upon drying in air for about 1 day, the films were tempered at 450 degrees C in air for 1 h. This procedure results in stoichiometric TiO(2) films with a thickness of several micro m and a milky whitish appearance. Scanning force microscopy of the surface revealed that the nanoparticles of the films agglomerated into structures with lateral dimensions of some 100 nm. Transmission electron microscopy was utilized to investigate the structural arrangement of the crystallites in the films. High-resolution electron diffraction and X-ray diffraction analyses demonstrated, furthermore, that the material consists exclusively of a single TiO(2) phase, namely anatase, and that the films do not exhibit any preferential texture. The elemental stoichiometry and the possible presence of impurities were monitored throughout the films by means of secondary-ion mass spectrometry depth profiling. Electrical measurements have been carried out as a function of both the sample temperature T and the ambient oxygen partial pressure p(O(2)). From these data the electrical conductivity sigma of the porous films was determined in dependence of those parameters.

Photocatalytic decomposition of methylene blue and 4-chlorophenol on nanocrystalline TiO2 films under UV illumination: A ToF-SIMS study

“…Generally, these procedures resulted in stoichiometric TiO 2 films with a thickness of several mm. They are composed of nanocrystallites with an average size identical to the original powder material, as determined by X-ray diffraction, Raman spectroscopy, and transmission electron microscopy [22][23][24]. The composition of the films and their stoichiometry were determined by dynamic SIMS depth profiling.…”

Photocatalytic degradation of methylene blue on nanocrystalline TiO2: Surface mass spectrometry of reaction intermediates

“…Calcination at 500 • C for 1 h resulted in stoichiometric TiO 2 films composed of nanocrystallites with an average size identical to the original powder material, as determined by X-ray diffraction and transmission electron microscopy [36,37]. Methylene blue (chloride) was dissolved in methanol (120 mg/L) and a single drop was applied onto the surface spreading over the ∼30 mm 2 nc-TiO 2 films.…”

Thermophysical properties study of micro/nanoscale materials

“…A varieties of techniques are used for have been employed for synthesizing TiO 2 nanostructures, such as sol-gel method [55][56][57][58][59][60][61], chemical vapor deposition [62,63], hydrothermal reaction [64][65][66][67][68][69][70], anodic oxidation [71][72][73][74][75], electrospinning [76][77][78][79][80][81][82][83] and many others [84][85][86][87][88][89][90][91][92][93]. [95], nanotubes [96,97], nanowires [98][99][100][101][102] and thin films [103]…”

“…Among all micro/nanostructures, TiO 2 thin film, which can be fabricated via several methods [103][104][105][106][107][108][109], is substantially important to several applications, such as protective coatings, microelectronic applications, optical coatings, and photochemically active layers.…”