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91.
Microstructure and ferroelectric properties of BaTiO3 films on LaNiO3 buffer layers by rf sputtering
We have fabricated LaNiO3 and BaTiO3 films using the rf sputtering method. The LaNiO3 were deposited on Si substrates, demonstrating a (1 0 0) highly oriented structure and nanocrystalline characteristic with a grain size of 30 nm. The BaTiO3 thin films were deposited on the LaNiO3 buffer layers, and have exhibited a (1 0 0) texture with a thickness of 400 nm. A smooth interface is obtained between the LaNiO3 bottom electrode and the BaTiO3 film from cross-section observations by scanning electron microscopy. The bi-layer films show a dense and column microstructure with a grain size of 60 nm. Ferroelectric characterizations have been obtained for the BaTiO3 films. The remnant polarization and coercive field are 2.1 μC/cm2 and 45 kV/cm, respectively. The leak current measurements have shown a good insulating property. 相似文献
92.
Hexagonal boron phosphide and boron arsenide van der Waals heterostructure as high-efficiency solar cell 下载免费PDF全文
The rapid development of two-dimensional (2D) materials offers new opportunities for 2D ultra-thin excitonic solar cells (XSCs). The construction of van der Waals heterostructure (vdWH) is a recognised and effective method of integrating the properties of single-layer 2D materials, creating particularly superior performance. Here, the prospects of h-BP/h-BAs vdW heterostructures in 2D excitonic solar cells are assessed. We systematically investigate the electronic properties and optical properties of heterogeneous structures by using the density functional theory (DFT) and first-principles calculations. The results indicate that the heterogeneous structure has good optoelectronic properties, such as a suitable direct bandgap and excellent optical absorption properties. The calculation of the phonon spectrum also confirms the well-defined kinetic stability of the heterstructure. We design the heterogeneous structure as a model for solar cells, and calculate its solar cell power conversion efficiency which reaches up to 16.51% and is higher than the highest efficiency reported in organic solar cells (11.7%). Our work illustrates the potential of h-BP/h-BAs heterostructure as a candidate for high-efficiency 2D excitonic solar cells. 相似文献
94.
Flower-like shaped Bi12TiO20 (Bismuth Titanate)/g-C3N4 (graphite-like carbon nitride) heterojunction was prepared through hydrothermal and sonification methods for the degradation of organic pollutants by visible-light irradiation. The preparation process, chemical structures, and the mechanism of photocatalytic enhancement of the heterostructures were studied systematically. Under visible-light irradiation, the novel flower-like shaped Bi12TiO20/g-C3N4 heterojunction demonstrates prominent activities for the degradation of rhodamine B and p-nitrophenol, with the introduction of flower-like shaped Bi12TiO20 into g-C3N4 composites greatly increasing the activity of pure g-C3N4. This activity enhancement for the heterojunction could be mainly attributed to its low recombination speed of electron–hole pairs, high adsorption ability of organic pollutants, and better optical absorption ability. Moreover, in the visible-light system of Bi12TiO20/g-C3N4, •OH also contributed to the degradation of pollutants, which may explain the enhanced photocatalytic activity after the introduction of Bi12TiO20, as •OH is inactive in pure g-C3N4. Furthermore, 10 wt.% Bi12TiO20/g-C3N4 showed not only high activity but also good stability for degradation of aqueous organic pollutants, implying potential applications prospect. 相似文献
95.
96.
Physical properties of titanates,semiconductors and nickelates derived from ionization energy theory
《Physics letters. A》2020,384(36):126917
Ionization energy theory is exploited to predict the changes to atomic polarizability for both anions and cations, the polarization in doped titanates and the energy gap in III–V and II–VI semiconductors. We then extend the above analysis to discuss the physics of metallic and superconducting phases in the recently discovered superconducting nickelates. In doing so, we are able to prove the existence of Ni2+ cations and oxygen vacancy in the metallic normal state of nickelates. We find that the normal state resistivity of the nickelates follows exactly as predicted by the ionization energy theory. Quantitative estimates are also given for the concentrations of Ni2+ and oxygen vacancy in superconducting nickelates. 相似文献
97.
We made comparative investigations on indium tin oxide (ITO) and single-layer graphene (SLG)-coated glass substrate as electrodes, specially for ferroelectric liquid crystal (FLC)-based system. We experimentally examined the comparative behaviour of important electro-optical FLC parameters for ITO- and SLG-based sample cells. The parameters are observed to be almost similar for both the cells. Interestingly, the value of threshold voltage is observed lower in SLG-based cell in comparison to that of conventional ITO/ITO cell. The presented results will definitely add a step to prove the suitability of graphene to be used as transparent electrodes in FLC-based display devices. 相似文献
98.
Recent theoretical developments regarding the understanding of weakly chaotic transients in ferroelectric liquid crystals (FLCs), induced by electric field, are studied in terms of the interaction with magnetic field. Our research is related with the nonlinear dynamical system represented by a thin film of surface-stabilized FLC in smectic C* phase, and subjected by the swinging magnetic field. The computation of the Lyapunov exponents from the dynamic equation for the director field reveals that the director dynamics exhibits limit cycle, hyperchaotic attractor and strange attractor behavior in the dissipative nonlinear media. The transients between director’s phase space trajectories can be handled by the magnetic field parameters. The fundamental understanding of the director dynamics may have a valuable contribution to the applications of thin liquid crystal films. 相似文献
99.
Jiagang Wu Dingquan Xiao Jianguo Zhu Jiliang Zhu Junzhe Tan 《Journal of Crystal Growth》2007,300(2):398-402
The (Pb0.90La0.10)TiO3 [PLT] thick films (3.0 μm) with a PbO buffer layer were deposited on the Pt(1 1 1)/Ti/SiO2/Si(1 0 0) substrates by RF magnetron sputtering method. The PLT thick films comprise five periodicities, the layer thicknesses of (Pb0.90La0.10)TiO3 and PbO in one periodicity are fixed. The PbO buffer layer improves the phase purity and electrical properties of the PLT thick films. The microstructure and electrical properties of the PLT thick films with a PbO buffer layer were studied. The PLT thick films with a PbO buffer layer possess good electrical properties with the remnant polarization (Pr=2.40 μC cm−2), coercive field (Ec=18.2 kV cm−1), dielectric constant (εr=139) and dielectric loss (tan δ=0.0206) at 1 kHz, and pyroelectric coefficient (9.20×10−9 C cm−2 K−1). The result shows the PLT thick film with a PbO buffer layer is a good candidate for pyroelectric detector. 相似文献
100.
Heterostructures of TiO2 with a biscyanine dye were obtained, and their photocatalytic activity in the reduction of methylene blue was investigated.
The results from analysis of the spectral parameters showed that the decrease of activity with increase of the dye content
results from weakening of its interaction with the semiconductor.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 44, No. 2, pp. 79–82, March–April, 2008. 相似文献