The stability, structural geometry, and electronic structure of the La-doped Sr1.9375La0.0625TiO3.968 75 are investigated by first-principles calculations based on the density functional theory. The calculated results reveal that the oxygen vacancies have a tendency to distribute in the ab planes of the perovskite SrTiO3 layer. The structural stability of Sr1.9375La0.0625TiO3.968 75 is weakened by the simultaneous substitution of La for Sr and the introduction of oxygen vacancies. After electron doping, the lattice parameter a increases while the lattice parameter c decreases. The corner-shared TiO6 octahedra dominate the main electronic properties of Sr2TiO4 and the Sr1.9375La0.0625TiO3.968 75 system shows n-type degenerate semiconductor features. There is an incipient localization of some of the doped electrons being trapped in the oxygen vacancy. The introduction of oxygen vacancy in Sr2TiO4 makes little contribution to the electrical activity of Sr1.9375La0.0625TiO3.968 75.

SnO2 nanocrystalline thin films (NCTFs) with high quality and low infrared emissivity were synthesized through a simple hydrothermal process designed by orthogonal design theory. The microstructure, morphology, photoluminescence (PL) property and the infrared emissivity (IRE) property of as-prepared products were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), fluorescence spectrophotometer, and infrared spectroradio meter (ISM) respectively. The results show that two emission peaks are observed in PL spectra, which can be deconvoluted by Gaussian profile fitting into four emission peaks centered at about 380, 420, 460 and 520 nm respectively. The influences of crystallinity, concentration of particles and resistivity on IRE were systematically investigated, revealing that the better crystallinity, higher particle density and better conductivity are favorable for lowering IRE.

The flower-like SnO2 particles are synthesized through a simple hydrothermal process. The microstructure, morphology and the infrared emissivity property of the as-prepared products are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and infrared spectroradio meter (ISM) respectively. The results show that the as-prepared SnO2 products are all indexed to tetragonal cassiterite phase of SnO2. The different molarity ratios of the OH− concentration to Sn4+ concentration ([OH−]:[Sn4+]) and the polyacrylamide (PAM) lead to the different morphological structures of SnO2, which indicates that both the [OH−]:[Sn4+] and the PAM play an important role in the morphological evolution respectively. The infrared emissivities of the as-prepared SnO2 products are discussed.

In this paper, vertically aligned ZnO nanorod arrays were synthesized by a simple hydrothermal process. The microstructure, morphology and optical properties of the as-prepared samples were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectrum (PL). The results show that the vertically aligned ZnO nanorod arrays are hexagonal wurtzite structures with the high (002)-orientation. At room temperature, the PL measurements illustrate that the as-prepared ZnO nanorod arrays exhibit a strong ultraviolet (UV) emission centered at about 378nm and a broad yellow-green emission centered at about 554 nm. A possible origin of the yellow-green emission of the ZnO nanorod arrays related to the intrinsic defect is proposed.

The electronic structure, band structure, density of states (DOS) and electronic density difference of paraelectric SrTiO3 in the cubic phase were performed by the first-principles calculation based on the density functional theory (DFT). The energy levels of high symmetry points in the Brillouin zone were listed and Mulliken population analysis was performed for valence bond structures. The top valence band of SrTiO3 is at the R point, and the minimum of the conduction bands is at the Γ point. The calculated value for indirect band gap is 1.84eV in the Brillouin zone. As in other perovskite ABO3 ferroelectrics, the population analysis, DOS and electron density difference show that there is a very strong hybridization between the Ti3d and O2p states in the valence bands, which is responsible for the ferroelectricity tendency.