Hydrothermal synthesis and formation mechanism of the single-crystalline Bi₄Ti₃O₁₂nanosheets with dominant (010) facets

Abstract

Single-crystalline bismuth-layered perovskite Bi 4 Ti 3 O 12 nanosheets with a thickness of about 20 nm and a lateral size over several micrometers have been synthesized by a PVA assisted hydrothermal route. The asprepared Bi 4 Ti 3 O 12 nanosheets were characterized by means of X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy (TEM) and high-resolution TEM. The as-prepared Bi 4 Ti 3 O 12 nanosheets have (010) dominated surface facets. Time-dependent experiments reveal that the layered K 2 Ti 6 O 13 nanofibers formed in the initial stage of the hydrothermal treatment play a key role in the synthesis of Bi 4 Ti 3 O 12 . In the proceeding hydrothermal treatment, the Bi 3+ ions substitute for the K + ions in the layered K 2 Ti 6 O 13 and peel off the TiO 6 octahedron lamellae from the lattice of K 2 Ti 6 O 13 , which then serves as a template for the formation of lamellar Bi 4 Ti 3 O 12 by reaction with the dehydrated Bi 3+ ions. Finally, the lamellar Bi 4 Ti 3 O 12 species crystallize and grow to single-crystalline Bi 4 Ti 3 O 12 nanosheets under the effect of the preferential adsorption of PVA on the (010) planes. In addition, the band gap and the optoelectronic properties of the single-crystalline Bi 4 Ti 3 O 12 nanosheets were investigated by measuring their UV-vis absorption and photoluminescence spectra, respectively.

Ferroelectric bismuth-titanate nanoplatelets and nanowires with a new crystal structure

“…11,12 BIT nanoparticles can be synthesized using a simple hydrothermal treatment of precipitated Bi 3+ and Ti 4+ ions in an aqueous alkali hydroxide at moderate concentrations. [6][7][8][9][11][12][13][14][15][16][17] Because of their layered structure the bismuth titanate nanoparticles tend to grow predominantly in the a/b plane to form 2-D rectangular platelet crystals, i.e., nanoplatelets and nanosheets, with the large surfaces parallel to the (001) crystal planes. 7,8,13,14,16,17 However, numerous other nanostructures including 1-D nanocrystals (e.g., nanowires, nanobelts, nano-bundles, nanorods), 7,8,15 and 3-D nanostructures assembled from 1-D or 2-D nanoparticles, 6,9,11,12,15,16 were synthesized using the hydrothermal method.…”

“…[6][7][8][9][11][12][13][14][15][16][17] Because of their layered structure the bismuth titanate nanoparticles tend to grow predominantly in the a/b plane to form 2-D rectangular platelet crystals, i.e., nanoplatelets and nanosheets, with the large surfaces parallel to the (001) crystal planes. 7,8,13,14,16,17 However, numerous other nanostructures including 1-D nanocrystals (e.g., nanowires, nanobelts, nano-bundles, nanorods), 7,8,15 and 3-D nanostructures assembled from 1-D or 2-D nanoparticles, 6,9,11,12,15,16 were synthesized using the hydrothermal method. The morphology of the BIT nanoparticles can be controlled by selecting the synthesis conditions, e.g., source of titania, type of mineralizer, reactant concentrations, reaction temperature and time, and use of surfactants.…”

“…The morphology of the BIT nanoparticles can be controlled by selecting the synthesis conditions, e.g., source of titania, type of mineralizer, reactant concentrations, reaction temperature and time, and use of surfactants. 7,8,15,17 In this investigation we synthesized BIT nanoplatelets (NPLs) and nanowires (NWs) just by changing the concentration of the NaOH during the hydrothermal treatment of precipitated Bi 3+ and Ti 4+ ions. Their characterization showed that both nanostructures are ferroelectric, but they differ in their crystal structure: the NPLs exhibit the Aurivillius-type structure characteristic for BIT, whereas the NWs exhibit an entirely new layered structure, not described before.…”

Review and Perspectives of Aurivillius Structures as a Lead-Free Piezoelectric System

“…They give place to ceramics with relatively high densities, as shown in Figure 2 [10] with good ferro/piezoelectric properties [7,11]. (b) Sol-gel.…”

“…The application to Aurivillius structure materials synthesis has been deeply explored in several works. Depending on variables such as time or temperature (<300 °C) [7], use of different mineralizers and concentrations [8] or starting materials [9], single phase materials with different sizes and shapes from the nanometric to micrometric scale can be synthesized. They give place to ceramics with relatively high densities, as shown in Figure 2 [10] with good ferro/piezoelectric properties [7,11].…”