Synthesis and Characterization of Ferroelectric Nanomaterials
In this dissertation, BaTiO3 nanocrystals, Bi4Ti3O12 nanostructured microspheres, and cosubstituted Bi4Ti3O12 nanoparticles and ceramics were prepared using solvothermal, hydrothermal and citrate-gel methods. The ferroelectric properties of the prepared cosubstituted Bi4Ti3O12 ceramics were studied...
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Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden
2008
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ndltd-DRESDEN-oai-qucosa.de-bsz-14-ds-1216128809669-532672013-01-07T19:48:01Z Synthesis and Characterization of Ferroelectric Nanomaterials Du, Hongchu Ferroelectrics Nanomaterials Electronic Ceramics Solvothermal Synthesis Perovskites 铁电体 纳米材料 电子陶瓷 钙钛矿 溶剂热合成 Nanotechnologie Nanopartikel nanostrukturiertes Material ddc:540 rvk:VE 9857 In this dissertation, BaTiO3 nanocrystals, Bi4Ti3O12 nanostructured microspheres, and cosubstituted Bi4Ti3O12 nanoparticles and ceramics were prepared using solvothermal, hydrothermal and citrate-gel methods. The ferroelectric properties of the prepared cosubstituted Bi4Ti3O12 ceramics were studied using P–E hysteresis loop, leakage, and polarization fatigue measurements. A two-phase solvothermal synthesis approach for the preparation of hydrophobic BaTiO3 nanocrystals was developed. The two-phase method is based on the growth of nanocrystals at the oil/water interface by the reaction between metal surfactant complexes in the oil phase and a mineralizer in the water phase. Three kind of organic solvents, hexadecene, toluene, and heptane were used as the oil phase and compared to each other with respect to the product quality. The BaTiO3 particles are crystalline with a mean size of 3.7 nm and can be dispersed in a variety of organic solvents forming highly transparent dispersions. A hydrothermal method was developed for the synthesis of Bi4Ti3O12 nanostructured microspheres consisting of granular nanoparticles and nano-platelets. The precursor powder was prepared using a diethylene glycol mediated coprecipitation method. Tailoring of the morphology was achieved by changing the precursor quantity, sodium hydroxide concentration, and reaction time. The formation mechanism of the nanostructured microspheres probably involves aggregation, followed by dissolution and recrystallization. Bi3.25Pr0.75Ti2.97V0.03O12 (BPTV) and Bi3.25La0.75Ti3-xMxO12, (BLTMx, M = Mo, W, Nb, V, x = 0.0–0.12) ferroelectric nanoparticles and ceramics were synthesized using a modified citrate-gel method that has a crystallization temperature as low as 450 °C. The synthesized nanoparticles were spherical ranging from 30 to 100 nm. Except Nb5+, other donor cations were introduced using the corresponding oxides that have advantages in terms of high purity, low cost, and availability. The Bi3.25Pr0.75Ti2.97V0.03O12 ceramic is orthorhombic and its 2Pr and 2Ec values measured at 300 kV/cm were 35 μC/cm2 and 148 kV/cm respectively. The texture, microstructure, and ferroelectric properties of the prepared Bi3.25La0.75Ti3-xMxO12, (BLTMx, M = Mo, W, Nb, V, x = 0.0–0.12) ceramics depend on x. The maximum 2Pr (30–32 μC cm−2) was achieved at an optimum cosubstitution level (x = 0.025 for M6+, x = 0.03 for M5+). The high remanent polarization, low leakage current, and low polarization fatigue render the prepared ceramics promising for practical applications. Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden Technische Universität Dresden, Chemie und Lebensmittelchemie Technische Universität Dresden, Institut für Anorganische Chemie Prof. Dr. Stefan Kaskel Prof. Dr. Stefan Kaskel Prof. Dr. Michael Ruck Prof. Dr. Stefan Ebbinghaus 2008-08-14 doc-type:doctoralThesis application/pdf http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1216128809669-53267 urn:nbn:de:bsz:14-ds-1216128809669-53267 PPN285189859 http://www.qucosa.de/fileadmin/data/qucosa/documents/28/1216128809669-5326.pdf eng |
collection |
NDLTD |
language |
English |
format |
Doctoral Thesis |
sources |
NDLTD |
topic |
Ferroelectrics Nanomaterials Electronic Ceramics Solvothermal Synthesis Perovskites 铁电体 纳米材料 电子陶瓷 钙钛矿 溶剂热合成 Nanotechnologie Nanopartikel nanostrukturiertes Material ddc:540 rvk:VE 9857 |
spellingShingle |
Ferroelectrics Nanomaterials Electronic Ceramics Solvothermal Synthesis Perovskites 铁电体 纳米材料 电子陶瓷 钙钛矿 溶剂热合成 Nanotechnologie Nanopartikel nanostrukturiertes Material ddc:540 rvk:VE 9857 Du, Hongchu Synthesis and Characterization of Ferroelectric Nanomaterials |
description |
In this dissertation, BaTiO3 nanocrystals, Bi4Ti3O12 nanostructured microspheres, and cosubstituted Bi4Ti3O12 nanoparticles and ceramics were prepared using solvothermal, hydrothermal and citrate-gel methods. The ferroelectric properties of the prepared cosubstituted Bi4Ti3O12 ceramics were studied using P–E hysteresis loop, leakage, and polarization fatigue measurements. A two-phase solvothermal synthesis approach for the preparation of hydrophobic BaTiO3 nanocrystals was developed. The two-phase method is based on the growth of nanocrystals at the oil/water interface by the reaction between metal surfactant complexes in the oil phase and a mineralizer in the water phase. Three kind of organic solvents, hexadecene, toluene, and heptane were used as the oil phase and compared to each other with respect to the product quality. The BaTiO3 particles are crystalline with a mean size of 3.7 nm and can be dispersed in a variety of organic solvents forming highly transparent dispersions. A hydrothermal method was developed for the synthesis of Bi4Ti3O12 nanostructured microspheres consisting of granular nanoparticles and nano-platelets. The precursor powder was prepared using a diethylene glycol mediated coprecipitation method. Tailoring of the morphology was achieved by changing the precursor quantity, sodium hydroxide concentration, and reaction time. The formation mechanism of the nanostructured microspheres probably involves aggregation, followed by dissolution and recrystallization. Bi3.25Pr0.75Ti2.97V0.03O12 (BPTV) and Bi3.25La0.75Ti3-xMxO12, (BLTMx, M = Mo, W, Nb, V, x = 0.0–0.12) ferroelectric nanoparticles and ceramics were synthesized using a modified citrate-gel method that has a crystallization temperature as low as 450 °C. The synthesized nanoparticles were spherical ranging from 30 to 100 nm. Except Nb5+, other donor cations were introduced using the corresponding oxides that have advantages in terms of high purity, low cost, and availability. The Bi3.25Pr0.75Ti2.97V0.03O12 ceramic is orthorhombic and its 2Pr and 2Ec values measured at 300 kV/cm were 35 μC/cm2 and 148 kV/cm respectively. The texture, microstructure, and ferroelectric properties of the prepared Bi3.25La0.75Ti3-xMxO12, (BLTMx, M = Mo, W, Nb, V, x = 0.0–0.12) ceramics depend on x. The maximum 2Pr (30–32 μC cm−2) was achieved at an optimum cosubstitution level (x = 0.025 for M6+, x = 0.03 for M5+). The high remanent polarization, low leakage current, and low polarization fatigue render the prepared ceramics promising for practical applications. |
author2 |
Technische Universität Dresden, Chemie und Lebensmittelchemie |
author_facet |
Technische Universität Dresden, Chemie und Lebensmittelchemie Du, Hongchu |
author |
Du, Hongchu |
author_sort |
Du, Hongchu |
title |
Synthesis and Characterization of Ferroelectric Nanomaterials |
title_short |
Synthesis and Characterization of Ferroelectric Nanomaterials |
title_full |
Synthesis and Characterization of Ferroelectric Nanomaterials |
title_fullStr |
Synthesis and Characterization of Ferroelectric Nanomaterials |
title_full_unstemmed |
Synthesis and Characterization of Ferroelectric Nanomaterials |
title_sort |
synthesis and characterization of ferroelectric nanomaterials |
publisher |
Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden |
publishDate |
2008 |
url |
http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1216128809669-53267 http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1216128809669-53267 http://www.qucosa.de/fileadmin/data/qucosa/documents/28/1216128809669-5326.pdf |
work_keys_str_mv |
AT duhongchu synthesisandcharacterizationofferroelectricnanomaterials |
_version_ |
1716470563136864256 |