Insight into the Mechanism of Nanoparticle-Aggregated Crystallization for Mesocrystals

摘要:

研究和探讨了银介观晶体的形成过程和机理，银介观晶体通过AgNO3溶液和Sn替换反应合成原始的纳米微粒。在200 mmol/L 浓度下，纳米颗粒沿着<211>方向聚集形成树突，银纳米颗粒是3×{422}位面；相应的，当浓度达到1 mol/L 时，形成的纳米颗粒在沿着<211>方向聚集的同时，在<110>方向形成第2个聚集单位，并最终形成多空的盘状结构的介观晶体，其厚度约为50 nm ；当浓度为2 mol/L时，纳米颗粒继续沿着<110>方向聚集，形成三角形的板状结构，随着聚集的越来越多，最终形成厚度超过100 nm 的单晶介观晶体

Abstract:

silver mesocrystals have been synthesized via oriented attachment of primary building nanoparticles in simple and fast replacement reactions between AgNO3 solution and Sn. The formation process of silver mesocrystals is discussed in detail and the growth mechanism is suggested to describe the formation of silver mesocrystals. In a 200 mmol/L solution, the primary nanoparticles orientationally aggregate along <211> directions to form a dendrite, the proposed attachment planes and directions for Ag nanoparticles are 3×{422} planes and <211> directions, respectively. When the concentration increases to 1 mol/L, the primary building nanoparticles orientotionally aggregate along <211> directions to form dendrites. The dendrites that can be proposed as the second building units orientationally attach along <110> directions to construct a porous monocrystalline plate, and finally transit to a mesocrystal with a thickness about 50 nm. When the AgNO3 concentration is 2 mol/L, the building units are Ag triangle platelets. These platelets also orientationally attach along <110> directions to form a monocrystalline dense plate and finally the plate transforms to monocrystalline mesocrystal with a thickness over 100 nm