Deng Shiqi, Xu Gang, Bai Huiwen, Li Lingling, Jiang Shan, Shen Ge, Han Gaorong
State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, and Key Laboratory of Advanced Materials and Applications for Battery of Zhejiang Province, Zhejiang University , Hangzhou 310027, China.
Inorg Chem. 2014 Oct 20;53(20):10937-43. doi: 10.1021/ic501180g. Epub 2014 Sep 29.
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.
通过使用层状K2Ti6O13纳米纤维作为钛源，成功合成了具有主导（001）面的单晶四方钙钛矿钛酸铅（PbTiO3）纳米片。通过X射线衍射、场发射扫描电子显微镜、透射电子显微镜（TEM）、高分辨率TEM和选区电子衍射对所制备的PbTiO3纳米片进行了表征。为了理解PbTiO3纳米片的形成机制，进行了一系列随时间变化的实验。由于Pb(2+)离子取代了K(+)离子，TiO6八面体薄片从层状K2Ti6O13晶体结构中剥离。然后，剥离的TiO6八面体薄片作为模板，通过与脱水的Pb(2+)离子反应转化为层状PbTiO3物种。随着水热处理时间的延长，层状PbTiO3物种结晶为单晶PbTiO3纳米片。此外，通过控制水热处理时间，合成的单晶PbTiO3纳米片的厚度可以在10-50nm范围内进行调整。此外，通过紫外-可见吸收和光致发光研究了单晶PbTiO3纳米片的带隙和光电性能。
