Papers by Keyword: Doped

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Authors: An Ning Zhou, Xiao Qin Wang, Jian Lin Qu, Yao Dong Wang, Yuan Gang Li, Guang Heng Wang
Abstract: After TiO2/SPAN (Sulfonated Polyaniline) complex prepared by the reverse-microemulsion method was calcinated, C, S & N-doped TiO2 was successfully synthesized with C/S/N/Ti atomic ratio of 12.5/12.2/1.3/100 and formaldehyde-degradation ratio of 58.5%. Its excited wavelength was red-shifted to 433.5 nm and its band gap was degraded to 2.87 eV. XPS analysis proved that C, S & N was doped into TiO2 lattice to form TiC, Ti(CO)n, Ti(CO3)2, Ti(SO3)2, TiS2, TiN and Ti(NO2)n.
Authors: Wen Song Lin, Jing Chen, Ji Zhou
Abstract: Iron-doped titanium nitride films deposed on glass substrates were prepared by magnetron sputtering technique. X-ray diffraction (XRD) was employed to analyze the phases existed in the films. Investigations have shown that as-deposited films were XRD-amorphous, and the TiN phase was formed in the film after additional annealing. It was found that iron-doped TiN films preserved the same crystal structure as TiN. The ferromagnetic properties of iron doped TiN films have been measured using vibrating sample magnetometer (VSM), and the electric resistances of the films were also determined by IR four-probe methods. The experiment results proved that the iron-doped TiN films possessed ferromagnetic property with low electric resistance at room temperature. It was investigated that the saturation magnetization was about 2.21×108 A/m, the coercivity about 23 kA/m, and the electric resisitivity 1.401×10-6 3•m for typical Fe-doped-TiN-films sample.
Authors: Qing Kai Xing, Zhi Jian Peng, Xiu Li Fu, Zhi Qiang Fu, Cheng Biao Wang, Long Hao Qi, He Zhuo Miao
Abstract: Mn-Zn ferrites doped with Cr3+ were prepared by “one-step synthesis” and conventional two-step synthesis methods, respectively. Their phase compositions and microstructures were characterized by X-ray diffraction and scanning electron microscopy, respectively. And their magnetic magnetic performance, such as saturation magnetization (Ms), magnetic hysteresis, initial permeability μi and power loss were comparatively investigated by vibrating sample magnetometer. It was observed that the difference of magnetic performance of the samples prepared by both methods is little. The similar performance of both methods makes the “one-step synthesis” especially attractive for application when considering energy economization.
Authors: Wei Wang, Cheng Xiang Li, Liu Si Sheng, Guo Bin Zhang
Abstract: In this paper,PANI/SSA thin films were deposited by MAPLE technique with different lasers. The structures and composition of films were characterized by XPS. The XPS results showed that because of the protection of matrix, the main structures and composition of films were protected effectively during deposition. While different lasers bring different influence to film structures. To short-wave laser, photochemical effect is obvious, the structures related to doping showed obvious change. To long-wave laser, photochemical effect did not bring obvious change to related structures, the XPS peaks showed no difference to that of PANI/SSA powder.
Authors: Xin Min Min, Guo Yi Wang
Abstract: The relations between electronic structure, chemical bond and thermoelectric property of misfit layered cobaltite of Ca3Co4O9 and 3d transitional metal (Ti, Cr, Mn, Fe and Cu) doped series are studied using density function and discrete variation method (DFT-DVM). Ca3Co4O9 consists of two layers of CoO2 and Ca2CoO3. The highest valence band (HVB) and the lowest conduction band (LCB) near Fermi level are only mainly from O 2p and Co 3d in Ca2CoO3 layer. Therefore, the semiconductor, or thermoelectric property of Ca3Co4O9 should be mainly from Ca2CoO3 layer, but it seems to have no direct relation to the CoO2 layer, which is consistent with that binary oxides hardly have thermoelectric property, but trinary oxide compounds have quite good thermoelectric property. The variation of electronic structure, chemical bond strength and thermoelectric property of doping series is discussed. The improvement of thermoelectric property of Cu-doped Ca3Co4O9 is the most obvious.
Authors: Shou Gang Chen, Wei Wei Sun, Shuai Qin Yu, Xun Jun Yin, Yan Sheng Yin
Abstract: Theoretical study on the electronic structure of small FemAln(m+n=6) clusters has been carried out at the BPW91 level, and the electronic structures, binding energy and vertical ionization potential of clusters were evaluated. For the stable clusters, the iron atoms gather together and form a maximum of Fe-Fe bonds, and the aluminum atoms locate around Fe core with a maximum of Fe-Al bonds. The binding energy and vertical ionization potential show that the Fe5Al, Fe4Al2 and Fe3Al3 clusters have higher stability, which results provide insight into the properties of iron-aluminides can be obtained from a finite size cluster model.
Authors: Bao Ping Li, Ben Niu, Jie Qiang Wang, Ping Li, Sun Hao Wang
Abstract: Aluminum nitride ceramics doped carbon nanotubes were fabricated by dispersed multi-walled carbon nanotubes (MWNTs) into AlN powders homogenously. The densification, electric resistance, thermal conductivity and relative dielectric constant of AlN ceramics were investigated. It was found that MWNTs additives could purify the grain boundaries. Furthermore, it induced the increase of the thermal conductivity and the decrease of the relative dielectric constant. However, the linear shrinkage and electric resistance decreased with increasing MWNTs amount. AlN ceramics with high thermal conductivity and low relative dielectric constant were obtained without apparent decrease of electric resistivity.
Authors: Zhi Guo Yan, Tong Jun Zhu, Ai Guo Xuan, Yuan Xin Wu
Abstract: First-principle software bundle based on the density functional theory (DFT) is used to investigate pure CeOB2B and Mn-doped CeOB2B with different doping concentration. The structural model of CeOB2B crystal is constructed and geometrically optimized, the electron density of states and band structure calculated. The results are as follows: the valence band top of CeOB2B is made up with O2p and Ce5d states, and the existence of 4f unoccupied molecular orbital of CeOB2B facilitates the electronic storage. The theoretical calculation models of Mn-doped CeOB2B with different concentration are constructed and calculated, including 2*1*1, 2*2*1 and 2*2*2 supercell models. After CeOB2B is doped, hybridization happens between 4s orbitals of Mn atoms and 2p orbital of O atoms, resulting in 4s orbitals of Mn atoms lose electrons.Moreover, Mn atom is electron donor and O atoms is the electron acceptor. As the doping concentration decreases, the formation energy also decreases.And a smaller formation energy leads to a more stable structure.
Authors: Sheng Qian Ma, Feng Li
Abstract: It is all known that the BN sheet is a nonmagnetic wide-band-gap semiconductor. Using Density Function Theory (DFT), the lattice parameters of Cr doped BN sheets were optimized, which were still kept on 2D planar geometry, and the band gap was studied. The simulation results show that the band gap is very easy to be tuned by Cr doped BN sheet, which is more stable structure. So Cr doped BN sheet is a promising material in modulating the band gap and through tuning the band gap it can be a highly efficient photocatalytic material et al. Because Cr is poisonous and harmful substance, it does harm to people’s health and environmental pollution, particularly, heavy metal contamination in soil. So Cr doped BN sheet is a promising material in modulating the band gap, through tuning the band gap it can be a highly efficient photocatalytic material and benefit humanity and protect the environment et al.
Authors: Gui Ying Ding, Wen Long Jiang, Guang De Wang, Qiang Han, Xi Chang
Abstract: The doped and non-doped white Organic light-emitting devices (OLEDs) were fabricated, using strong yellow emitting and hole-transporting ability of TPAHQZn. When the white OLED is a double-doped structure, greatly enhanced the efficiency of the device. The double-doped white device were fabricated as follows: ITO/2T-NATA (17 nm)/ CBP: 30% TPAHQZn: 8% Ir(ppy)3 (25 nm)/ NPBX (15 nm)/BCP(8nm)/TPBi: 10% Ir(ppy)3 (15nm)/Alq3 (20 nm)/LiF (1.3 nm)/Al. The double-doped white OLEDs were obtained with Commission International de L’Eclairage coordinates of (0.29,0.28) at 17 V, the maximum current efficiency increaed four times that double-doped white device of 4.12cd/A(8V) than non-doped of 1.03 cd/A (10V) .
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