Bi4Ti3O12 （BIT） crystals were controllably synthesized via a facile hydrothermal process without adding any surfactant or template. The morphologies of BIT with nanosphere, nanoplate, nanobelt, and nanosheet can be ...Bi4Ti3O12 （BIT） crystals were controllably synthesized via a facile hydrothermal process without adding any surfactant or template. The morphologies of BIT with nanosphere, nanoplate, nanobelt, and nanosheet can be selectively obtained by adjusting the pH value of the reactant. The formation mechanisms of these distinctive morphologies were then discussed based on the structural analysis of samples obtained at different pH values. BIT sample prepared at pH=1 showed the highest photocatalytic activity under visible light irradiation. The photocatalytic activities difference for the BIT samples synthesized at different pH values was studied based on their shape, size, and the variation of local structure.展开更多
We report a distinctive way for designing lead-free films with high energy storage performance.By inserting different single perovskite cells into Bi4 Ti3 O12,P-E hysteresis loops present larger maximum polarization,h...We report a distinctive way for designing lead-free films with high energy storage performance.By inserting different single perovskite cells into Bi4 Ti3 O12,P-E hysteresis loops present larger maximum polarization,higher breakdown strength and smaller slim-shaped area.We prepared 0.15 Bi7 Fe3 Ti3 O21-0.5 Bi4 Sr3 Ti6 O21-0.35 Bi4 Ba3 Ti6 O21 solid solution ferroelectric films employing the sol-gel method,and obtained high energy storage density of 132.5 J/cm3 and efficiency of 78.6%while maintaining large maximum polarization of 112.3μC/cm2 and a high breakdown electric field of 3700 kV/cm.Moreover,the energy storage density and efficiency exhibit stability over the temperature range from 20℃to 125℃,and anti-fatigue stability maintains up to 108 cycles.The films with a simple preparation method and high energy storage performance are likely to become candidates for high-performance energy storage materials.展开更多
Chemical solution route was used to synthesize Bi3.1La0.9Ti3O12 and CoFe2O4. Alternate CoFe2O4/Bi3.1La0.9Ti3O12 layers were deposited on Pt substrate （Pt/TiO2/SiO2/Si） by spin coating. X-ray diffraction and SEM （sc...Chemical solution route was used to synthesize Bi3.1La0.9Ti3O12 and CoFe2O4. Alternate CoFe2O4/Bi3.1La0.9Ti3O12 layers were deposited on Pt substrate （Pt/TiO2/SiO2/Si） by spin coating. X-ray diffraction and SEM （scanning electron microscopy） studies show composite-like polycrystalline films. Films were studied for leakage current, dielectric response, ferroelectric and ferromagnetic properties. Leakage current was low （〈 10^-8 A） in electric field below 120 kV/cm, and the dielectric response shows relaxation. Dielectric loss （tan 8） reduces 〈 3% at 10^6 Hz. Two and four layer structures showed room temperature FE （ferroelectric） and FM （ferromagnetic） responses with FE Pr （polarization） 〉 25℃/cm2 and ferromagnetic Mr （memory） 〉 52 emu/cm3. Co-existence of FE and FM can be attributed to stress due to different crystal structures of the material involved in composite film structure.展开更多
Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth condit...Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth conditions. The relationship between the structure and ferroelectric property of the films was investigated, so as to explore the possibility of enhancing ferroelectric polarization by controlling the preferred orientation. The structural characterization indicated that the large growth rate and high oxygen background pressure were both favorable for the growth of non-c-axis oriented grains in the Bi_4Ti_3O_（12） thin films. The films with high fractions of a-axis and random orientations, i e, f（a-sxis） = 28.3% and f（random） = 69.6%, could be obtained at the deposition temperature of 973 K, oxygen partial pressure of 15 Pa and laser fluence of 4.6 J/cm^2, respectively. It was also noted that the variation of ferroelectric polarization was in accordance with the evolution non-c-axis orientation. A large value of remanent polarization（2 Pr = 35.5 μC/cm^2） was obtained for the Bi_4Ti_3O_（12） thin films with significant non-c-axis orientation, even higher than that of rare-earth-doped Bi_4Ti_3O_（12） films.展开更多
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.61308095）, China Postdoctoral Science Foundation （No.2013M531286）, the Key Laboratory of Preparation and Application Environmentally Friendly Materials of the Ministry of Education of China, and the Science Development Project of Jilin Province No.20130102004JC）. （No.20130522071JH and
文摘Bi4Ti3O12 （BIT） crystals were controllably synthesized via a facile hydrothermal process without adding any surfactant or template. The morphologies of BIT with nanosphere, nanoplate, nanobelt, and nanosheet can be selectively obtained by adjusting the pH value of the reactant. The formation mechanisms of these distinctive morphologies were then discussed based on the structural analysis of samples obtained at different pH values. BIT sample prepared at pH=1 showed the highest photocatalytic activity under visible light irradiation. The photocatalytic activities difference for the BIT samples synthesized at different pH values was studied based on their shape, size, and the variation of local structure.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11864028 and 12074204)。
文摘We report a distinctive way for designing lead-free films with high energy storage performance.By inserting different single perovskite cells into Bi4 Ti3 O12,P-E hysteresis loops present larger maximum polarization,higher breakdown strength and smaller slim-shaped area.We prepared 0.15 Bi7 Fe3 Ti3 O21-0.5 Bi4 Sr3 Ti6 O21-0.35 Bi4 Ba3 Ti6 O21 solid solution ferroelectric films employing the sol-gel method,and obtained high energy storage density of 132.5 J/cm3 and efficiency of 78.6%while maintaining large maximum polarization of 112.3μC/cm2 and a high breakdown electric field of 3700 kV/cm.Moreover,the energy storage density and efficiency exhibit stability over the temperature range from 20℃to 125℃,and anti-fatigue stability maintains up to 108 cycles.The films with a simple preparation method and high energy storage performance are likely to become candidates for high-performance energy storage materials.
文摘Chemical solution route was used to synthesize Bi3.1La0.9Ti3O12 and CoFe2O4. Alternate CoFe2O4/Bi3.1La0.9Ti3O12 layers were deposited on Pt substrate （Pt/TiO2/SiO2/Si） by spin coating. X-ray diffraction and SEM （scanning electron microscopy） studies show composite-like polycrystalline films. Films were studied for leakage current, dielectric response, ferroelectric and ferromagnetic properties. Leakage current was low （〈 10^-8 A） in electric field below 120 kV/cm, and the dielectric response shows relaxation. Dielectric loss （tan 8） reduces 〈 3% at 10^6 Hz. Two and four layer structures showed room temperature FE （ferroelectric） and FM （ferromagnetic） responses with FE Pr （polarization） 〉 25℃/cm2 and ferromagnetic Mr （memory） 〉 52 emu/cm3. Co-existence of FE and FM can be attributed to stress due to different crystal structures of the material involved in composite film structure.
基金Funded by the International Science and Technology Cooperation Project of Hubei Province(2016AHB008)the Natural Science Foundation of Hubei Province(2015CFB724,2016CFA006)+1 种基金the National Natural Science Foundation of China(51272195,51521001)the National Key Research and Development Program of China(2017YFB0310400)
文摘Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth conditions. The relationship between the structure and ferroelectric property of the films was investigated, so as to explore the possibility of enhancing ferroelectric polarization by controlling the preferred orientation. The structural characterization indicated that the large growth rate and high oxygen background pressure were both favorable for the growth of non-c-axis oriented grains in the Bi_4Ti_3O_（12） thin films. The films with high fractions of a-axis and random orientations, i e, f（a-sxis） = 28.3% and f（random） = 69.6%, could be obtained at the deposition temperature of 973 K, oxygen partial pressure of 15 Pa and laser fluence of 4.6 J/cm^2, respectively. It was also noted that the variation of ferroelectric polarization was in accordance with the evolution non-c-axis orientation. A large value of remanent polarization（2 Pr = 35.5 μC/cm^2） was obtained for the Bi_4Ti_3O_（12） thin films with significant non-c-axis orientation, even higher than that of rare-earth-doped Bi_4Ti_3O_（12） films.
