Formation Mechanism of (001) Oriented Perovskite SrTiO₃ Microplatelets Synthesized by Topochemical Microcrystal Conversion

Abstract

To develop a better understanding of the mechanism responsible for topochemical microcrystal conversion (TMC) from Aurivillius SrBi4Ti4O15 precursors to perovskite SrTiO3 microplatelets, compositional/structural evolutions, morphological development, and reaction interface evolution of the (001) oriented SrBi4Ti4O15 microplatelets were investigated during the conversion process. The results show that multiple topotactic nucleation events of SrTiO3 occurred directly on the surfaces of SrBi4Ti4O15 above 700 °C, while reacting zones of intermediate phase(s) with less Bi(3+) contents were observed to form in the interior of SrBi4Ti4O15. Extensive exfoliation of the precursors occurred generally parallel to the (001) surfaces above 775 °C. At 950 °C, the original single-crystal SrBi4Ti4O15 platelet was replaced by a polycrystalline aggregate consisting of (001) aligned SrTiO3 crystallites and poorly crystallized intermediate phase(s). With further increasing the temperature or holding time, the SrTiO3 phase formed from related intermediate phase(s), and the aligned crystallites were sintered to form dense SrTiO3 with strong (001) orientation. The obtained SrTiO3 microplatelets preserved the shape of SrBi4Ti4O15 and show high chemical and phase purity. This TMC mechanism has general applicability to a variety of compounds and will be very useful for the design and synthesis of novel anisotropic perovskite crystals with high quality in the future.

Highly oriented BaTiO3 film self-assembled using an interfacial strategy and its application as a flexible piezoelectric generator for wind energy harvesting

“…Since particles with a plate shape are easier to assemble on the water/oil interface, 34 how to synthesize plate-like particles becomes a signicant issue for the assembly of particles into a lm using an interface strategy. Recently a topochemical conversion method has been applied to the greatest extent in other perovskite systems, such as BaTiO 3 , 38 Na 0.5 Bi 0.5 TiO 3 , 39 SrTiO 3 , 40,41 PbTiO 3 . 42 These kinds of particles with a highaspect ratio and special orientation would provide excellent templates for the preparation of preferred orientation relevant perovskite ferroelectrics, and the other key issue is how to assemble these templates to form preferred orientation structures.…”

Enhanced electromechanical properties and phase transition temperatures in [001] textured Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ternary ceramics

“…[10][11][12][13][14][15][16][17][18][19][20] In TGG or RTGG, aligned template particles are used to direct oriented grain growth within a dense, fine-grained ceramic matrix. 21 Recently, several published reports have demonstrated that highly [001] textured PMN-PT binary ceramics exhibit substantially enhanced piezoelectric coefficient and high electromechanical coupling factor. [22][23][24][25][26][27][28] Thus, it is expected that [001] oriented PIN-PMN-PT ternary ceramics would exhibit high and much more stable electrical performance as compared to binary PMN-PT textured ceramics.…”

Mesocrystals for photocatalysis: a comprehensive review on synthesis engineering and functional modifications

“…Based on the previous literature, it can be found that the hydrothermal topotactic epitaxy of titanate was an effective strategy for the controllable synthesis of SrTiO 3 mesocrystals. 104,105 For instance, Majima and coworkers have prepared a novel perovskite SrTiO 3 mesocrystal superstructure with well-dened orientation of assembled cubic nanocrystals induced by topotactic epitaxy from TiO 2 mesocrystals through a facile hydrothermal treatment. 105 In this case, starting from sheet-like TiO 2 mesocrystals, which consisted of assembled anatase TiO 2 nanocrystals with dominant (001) facets, Sr 2+ ions from Sr(OH) 2 reacted with TiO 2 in an alkaline solution to generate an epitaxial overlayer of SrTiO 3 grains at the interface via the dissolution-precipitation process.…”