TY - JOUR
T1 - Mesoporous TiO2 mesocrystals
T2 - remarkable defects-induced crystallite-interface reactivity and their in situ conversion to single crystals
AU - Liu, Yong
AU - Luo, Yongfeng
AU - Elzatahry, Ahmed A.
AU - Luo, Wei
AU - Che, Renchao
AU - Fan, Jianwei
AU - Lan, Kun
AU - Al-Enizi, Abdullah M
AU - Sun, Zhenkun
AU - Li, Bin
AU - Liu, Zhengwang
AU - Shen, Dengke
AU - Ling, Yun
AU - Wang, Chun
AU - Wang, Jinxiu
AU - Gao, Wenjun
AU - Yao, Chi
AU - Yuan, Kaiping
AU - Peng, Huisheng
AU - Tang, Yun
AU - Deng, Yonghui
AU - Zheng, Gengfeng
AU - Zhou, Gang
AU - Zhao, Dongyuan
PY - 2015/10/28
Y1 - 2015/10/28
N2 - Oriented self-assembly between inorganic nanocrystals and surfactants is emerging as a route for obtaining new mesocrystalline semiconductors. However, the actual synthesis of mesoporous semiconductor mesocrystals with abundant surface sites is extremely difficult, and the corresponding new physical and chemical properties arising from such an intrinsic porous mesocrystalline nature, which is of fundamental importance for designing high-efficiency nanostructured devices, have been rarely explored and poorly understood. Herein, we report a simple evaporation-driven oriented assembly method to grow unprecedented olive-shaped mesoporous TiO2 mesocrystals (FDU-19) self-organized by ultrathin flake-like anatase nanocrystals (~8 nm in thickness). The mesoporous mesocrystals FDU-19 exhibit an ultrahigh surface area (~189 m2/g), large internal pore volume (0.56 cm3/g), and abundant defects (oxygen vacancies or unsaturated Ti3+ sites), inducing remarkable crystallite-interface reactivity. It is found that the mesocrystals FDU-19 can be easily fused in situ into mesoporous anatase single crystals (SC-FDU-19) by annealing in air. More significantly, by annealing in a vacuum (~4.0 × 10-5 Pa), the mesocrystals experience an abrupt three-dimensional to two-dimensional structural transformation to form ultrathin anatase single-crystal nanosheets (NS-FDU-19, ~8 nm in thickness) dominated by nearly 90% exposed reactive (001) facets. The balance between attraction and electrostatic repulsion is proposed to determine the resulting geometry and dimensionality. Dye-sensitized solar cells based on FDU-19 and SC-FDU-19 samples show ultrahigh photoconversion efficiencies of up to 11.6% and 11.3%, respectively, which are largely attributed to their intrinsic single-crystal nature as well as high porosity. This work gives new understanding of physical and chemical properties of mesoporous semiconductor mesocrystals and opens up a new pathway for designing various single-crystal semiconductors with desired mesostructures for applications in catalysis, sensors, drug delivery, optical devices, etc.
AB - Oriented self-assembly between inorganic nanocrystals and surfactants is emerging as a route for obtaining new mesocrystalline semiconductors. However, the actual synthesis of mesoporous semiconductor mesocrystals with abundant surface sites is extremely difficult, and the corresponding new physical and chemical properties arising from such an intrinsic porous mesocrystalline nature, which is of fundamental importance for designing high-efficiency nanostructured devices, have been rarely explored and poorly understood. Herein, we report a simple evaporation-driven oriented assembly method to grow unprecedented olive-shaped mesoporous TiO2 mesocrystals (FDU-19) self-organized by ultrathin flake-like anatase nanocrystals (~8 nm in thickness). The mesoporous mesocrystals FDU-19 exhibit an ultrahigh surface area (~189 m2/g), large internal pore volume (0.56 cm3/g), and abundant defects (oxygen vacancies or unsaturated Ti3+ sites), inducing remarkable crystallite-interface reactivity. It is found that the mesocrystals FDU-19 can be easily fused in situ into mesoporous anatase single crystals (SC-FDU-19) by annealing in air. More significantly, by annealing in a vacuum (~4.0 × 10-5 Pa), the mesocrystals experience an abrupt three-dimensional to two-dimensional structural transformation to form ultrathin anatase single-crystal nanosheets (NS-FDU-19, ~8 nm in thickness) dominated by nearly 90% exposed reactive (001) facets. The balance between attraction and electrostatic repulsion is proposed to determine the resulting geometry and dimensionality. Dye-sensitized solar cells based on FDU-19 and SC-FDU-19 samples show ultrahigh photoconversion efficiencies of up to 11.6% and 11.3%, respectively, which are largely attributed to their intrinsic single-crystal nature as well as high porosity. This work gives new understanding of physical and chemical properties of mesoporous semiconductor mesocrystals and opens up a new pathway for designing various single-crystal semiconductors with desired mesostructures for applications in catalysis, sensors, drug delivery, optical devices, etc.
UR - http://www.scopus.com/inward/record.url?scp=84983024840&partnerID=8YFLogxK
U2 - 10.1021/acscentsci.5b00256
DO - 10.1021/acscentsci.5b00256
M3 - Article
SN - 2374-7951
VL - 1
SP - 400
EP - 408
JO - ACS Central Science
JF - ACS Central Science
IS - 7
ER -