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.

A spiro-OMeTAD/mesoporous TiO2 heterojunction structure was developed for a highly sensitive and air-stable ultraviolet photodetector.

Quantum dot sensitized solar cell assembled with a nanostructured Cu3Se2 counter electrode exhibits a high power conversion efficiency of 5.05%.

3D flower-like PbTiO 3 nanostructures self-assembled with (101) nanosheets have been realized by the hydrothermal treatment of the mixture of the lead and titanium hydroxides under the effect of high KOH concentration. The layered K 2 Ti 6 O 13 formed in situ under the effect of the high KOH concentration plays an important role in the crystallization of the primary PbTiO 3 nanosheets and the further self-assembly of the 3D flower-like perovskite PbTiO 3 nanostructures. The self-assembled 3D flower-like perovskite PbTiO 3 nanostructures express good mesoporous structures and high specific surface area. In consequence, the 3D flower-like perovskite PbTiO 3 nanostructures as supports show excellent ability to enhance the catalytic activity of Pt. Over the Pt/PbTiO 3 nanoflowers, the CO instantaneously completely converts to CO 2 at a very low temperature of ca. 107 C facilitating the catalytic purification of the automotive exhaust produced in the cold-start period.

Single-crystalline tetragonal perovskite lead titanate (PbTiO3) nanosheets with dominant (001) facets have been successfully synthesized by employing layered K2Ti6O13 nanofibers as titanium sources. The as-prepared PbTiO3 nanosheets were characterized by means of X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, and selected-area electron diffraction. In order to understand the formation mechanism of the PbTiO3 nanosheets, a series of time-dependent experiments were performed. Because of the substitution of Pb(2+) ions for K(+) ions, the TiO6 octahedral lamellas exfoliate from the layered K2Ti6O13 crystal structure. Then the exfoliated TiO6 octahedral lamellas as templates transform to lamellar PbTiO3 species by reacting with the dehydrated Pb(2+) ions. With hydrothermal treatment prolongation, the lamellar PbTiO3 species crystallize to single-crystalline PbTiO3 nanosheets. Moreover, the thickness of the synthesized single-crystalline PbTiO3 nanosheets can be tailored in the range of 10-50 nm by controlling the hydrothermal treatment time. In addition, the band gap and the optoelectronic properties of the single-crystalline PbTiO3 nanosheets are investigated by UV-vis absorption and photoluminescence.