In the present work, we prepared two kinds of quantum sized ZnO particles whose size were 3 nm(P1) and 5 nm(P2), respectively, and studied their surface properties with surface photovoltage spectroscopy(SPS) and elect...In the present work, we prepared two kinds of quantum sized ZnO particles whose size were 3 nm(P1) and 5 nm(P2), respectively, and studied their surface properties with surface photovoltage spectroscopy(SPS) and electric field induced surface photovoltage spectroscopy(EFISPS). The photovoltaic response of the two samples showed opposite dependence on external electric field. And when electric field was applied, the thresholds of photovoltaic response of the two samples were all red shifted. The results showed that the surface properties of P1 were different from those of P2, because of their different preparation process. We assigned that basic zinc acetate structure exist on the surface of P1 sample. While for P2 sample prepared by aging P1, that kind of surface structure disappeared, but the particles might be doped with lithium ions in the aging process.展开更多
The colloids of ZnO and WO 3 were synthesized and ZnO colloid with different mass fractions was added into the WO 3 colloid to get WO 3/ZnO composite colloids. The experimental results indicate that the UV-light color...The colloids of ZnO and WO 3 were synthesized and ZnO colloid with different mass fractions was added into the WO 3 colloid to get WO 3/ZnO composite colloids. The experimental results indicate that the UV-light coloration of WO 3 nanoparticles could be improved greatly after the addition of ZnO. When the molar ratio of ZnO to WO 3 is about 1∶100, the magnitude of the difference of absorbance(ΔOD) at 900 nm after and before the coloration for WO 3/ZnO colloids is as about 135 times as that of WO 3 colloids. The surface photovoltaic spectra show that the state density of the surface state of WO 3 increases greatly after the addition of ZnO, thus, under the UV-light irradiation more electrons from ZnO nanoparticles can be captured in the surface state and those electrons can be excited to a higher energy level, resulting in the improved coloration.展开更多
The recent progresses on constructing organic nanostructures from the self-assembly of melamine and barbituric acid derivatives are reviewed. By mediating the chemical microenvironment during the self-assembly, the in...The recent progresses on constructing organic nanostructures from the self-assembly of melamine and barbituric acid derivatives are reviewed. By mediating the chemical microenvironment during the self-assembly, the information contained in the molecular components can be expressed at different levels, thus resulting in the formation of different organic nanostructures. When the assembly is carried out in anhydrous chloroform, a kind of asymmetric layered structure with a d value of 4.1 nm is obtained. When a little amount of polar solvent such as alcohol is contained in the chloroform, organic nanotubes with diameter of 6 nm and length of several hundreds of nanometers are observed. After being treated by appropriate polar solvents, the nanotubes are induced into supercoils with diameter of about 300 nm and length of several tens of microns. The sensitivity of the self-assembly process origins from the weak noncovalent intermolecular interactions between the molecular components. The enthalpy change of such interactions is pretty small, so slight change of the molecular structure or microenvironment could affect the primary equilibrium, resulting in the rearrangement and transformation of the supramolecular structure.展开更多
Two complemental 2′-phosphorothioate oligo-DNA compounds were used as linker molecules to provide the necessary symmetry-breaking mechanism to direct the assembly of 13 nm Au nanoparticles into aggregates with anisot...Two complemental 2′-phosphorothioate oligo-DNA compounds were used as linker molecules to provide the necessary symmetry-breaking mechanism to direct the assembly of 13 nm Au nanoparticles into aggregates with anisotropic optical properties.展开更多
文摘In the present work, we prepared two kinds of quantum sized ZnO particles whose size were 3 nm(P1) and 5 nm(P2), respectively, and studied their surface properties with surface photovoltage spectroscopy(SPS) and electric field induced surface photovoltage spectroscopy(EFISPS). The photovoltaic response of the two samples showed opposite dependence on external electric field. And when electric field was applied, the thresholds of photovoltaic response of the two samples were all red shifted. The results showed that the surface properties of P1 were different from those of P2, because of their different preparation process. We assigned that basic zinc acetate structure exist on the surface of P1 sample. While for P2 sample prepared by aging P1, that kind of surface structure disappeared, but the particles might be doped with lithium ions in the aging process.
文摘The colloids of ZnO and WO 3 were synthesized and ZnO colloid with different mass fractions was added into the WO 3 colloid to get WO 3/ZnO composite colloids. The experimental results indicate that the UV-light coloration of WO 3 nanoparticles could be improved greatly after the addition of ZnO. When the molar ratio of ZnO to WO 3 is about 1∶100, the magnitude of the difference of absorbance(ΔOD) at 900 nm after and before the coloration for WO 3/ZnO colloids is as about 135 times as that of WO 3 colloids. The surface photovoltaic spectra show that the state density of the surface state of WO 3 increases greatly after the addition of ZnO, thus, under the UV-light irradiation more electrons from ZnO nanoparticles can be captured in the surface state and those electrons can be excited to a higher energy level, resulting in the improved coloration.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 50172019) the Excellent Young Teachers Program of Ministry of Education, China.
文摘The recent progresses on constructing organic nanostructures from the self-assembly of melamine and barbituric acid derivatives are reviewed. By mediating the chemical microenvironment during the self-assembly, the information contained in the molecular components can be expressed at different levels, thus resulting in the formation of different organic nanostructures. When the assembly is carried out in anhydrous chloroform, a kind of asymmetric layered structure with a d value of 4.1 nm is obtained. When a little amount of polar solvent such as alcohol is contained in the chloroform, organic nanotubes with diameter of 6 nm and length of several hundreds of nanometers are observed. After being treated by appropriate polar solvents, the nanotubes are induced into supercoils with diameter of about 300 nm and length of several tens of microns. The sensitivity of the self-assembly process origins from the weak noncovalent intermolecular interactions between the molecular components. The enthalpy change of such interactions is pretty small, so slight change of the molecular structure or microenvironment could affect the primary equilibrium, resulting in the rearrangement and transformation of the supramolecular structure.
基金Project supported by the National Natural Science Foundation of China （No. 60171022）.
文摘Two complemental 2′-phosphorothioate oligo-DNA compounds were used as linker molecules to provide the necessary symmetry-breaking mechanism to direct the assembly of 13 nm Au nanoparticles into aggregates with anisotropic optical properties.
