The common Au nanostructures(nanospheres,nanorods and nanosheets)were prepared by the seed growth method to explore the cold welding phenomenon of these non-single crystal nanostructures at room temperature.Systematic...The common Au nanostructures(nanospheres,nanorods and nanosheets)were prepared by the seed growth method to explore the cold welding phenomenon of these non-single crystal nanostructures at room temperature.Systematic studies show that the concentration of surfactant cetyltrimethylammonium bromide(CTAB)and drying conditions are important factors to determine the evolution and final configuration of nanostructures during welding.The key factor of cold welding is the concentration of surfactant as low as 0.3 mm/L,and the welding should be carried out under the condition of slow evaporation and sufficient relaxation time,rather than rapid drying process.At the same time,the structural evolution during the welding process of gold rod head and tail is simulated by combining the electronic microscope characterization and density functional theory,which reveals that the stability of the welding nanostructure is better than that of the dispersed nanostructure.In the slow evaporation process of Au nanostructures with the same crystal structure,the low surfactant attached to the surface of the nanoparticles increases the attraction between the nanoparticles,which makes the nanoparticles close to each other adhere due to the interaction,and improves the physical properties of the intersection due to the diffusion,epitaxy and surface relaxation of the metal surface atoms.The results provide a research basis for the physical property analysis of nanostructures and the construction of defect devices.展开更多
基金supported by the National Natural Science Foundations of China (Nos. 11774171,11874220,21805137)the Open Funds of Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education (Nos. INMD-2019M02, INMD2020M03)+1 种基金the Scientific Foundation of Nanjing Institute of Technology(No. CKJB201708)the Fundamental Research Funds for the Central Universities(No.NS2017047) provided by Nanjing University of Aeronautics and Astronautics
文摘The common Au nanostructures(nanospheres,nanorods and nanosheets)were prepared by the seed growth method to explore the cold welding phenomenon of these non-single crystal nanostructures at room temperature.Systematic studies show that the concentration of surfactant cetyltrimethylammonium bromide(CTAB)and drying conditions are important factors to determine the evolution and final configuration of nanostructures during welding.The key factor of cold welding is the concentration of surfactant as low as 0.3 mm/L,and the welding should be carried out under the condition of slow evaporation and sufficient relaxation time,rather than rapid drying process.At the same time,the structural evolution during the welding process of gold rod head and tail is simulated by combining the electronic microscope characterization and density functional theory,which reveals that the stability of the welding nanostructure is better than that of the dispersed nanostructure.In the slow evaporation process of Au nanostructures with the same crystal structure,the low surfactant attached to the surface of the nanoparticles increases the attraction between the nanoparticles,which makes the nanoparticles close to each other adhere due to the interaction,and improves the physical properties of the intersection due to the diffusion,epitaxy and surface relaxation of the metal surface atoms.The results provide a research basis for the physical property analysis of nanostructures and the construction of defect devices.
