Son Dong Hee, Hughes Steven M, Yin Yadong, Paul Alivisatos A
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Science. 2004 Nov 5;306(5698):1009-12. doi: 10.1126/science.1103755.
Cation exchange has been investigated in a wide range of nanocrystals of varying composition, size, and shape. Complete and fully reversible exchange occurs, and the rates of the reactions are much faster than in bulk cation exchange processes. A critical size has been identified below which the shapes of complex nanocrystals evolve toward the equilibrium shape with lowest energy during the exchange reaction. Above the critical size, the anion sublattice remains intact and the basic shapes of the initial nanocrystals are retained throughout the cation exchange. The size-dependent shape change can also be used to infer features of the microscopic mechanism.
阳离子交换已在各种不同组成、尺寸和形状的纳米晶体中展开研究。完全且完全可逆的交换会发生，并且反应速率比体相阳离子交换过程快得多。已确定了一个临界尺寸，低于该尺寸时，复杂纳米晶体的形状在交换反应过程中会朝着能量最低的平衡形状演化。高于临界尺寸时，阴离子亚晶格保持完整，并且初始纳米晶体的基本形状在整个阳离子交换过程中得以保留。尺寸依赖性形状变化还可用于推断微观机制的特征。
