Solid State Intercalation, Deintercalation, and Cation Exchange in Colloidal 2D Bi2Se3 and Bi2Te3 Nanocrystals
文摘
Intercalation and deintercalation of Cu into and from Bi2Se3 and Bi2Te3 colloidal nanocrystals is demonstrated in solid state. For this purpose, the nanocrystals are deposited on a solid substrate and subjected to moderate heating in the presence of a Cu source or a Cu scavenger. The results of the solid state experiments are consistent with those produced by solution-based intercalation. At moderate levels of solid state intercalation above about 10 at%, Cu forms superlattice structures in both Bi2Se3 and Bi2Te3, while higher intercalation levels ultimately lead to cation exchange. This is particularly the case in Bi2Se3 which transitions to Cu2-xSe while maintaining the two-dimensional morphology of the starting nanocrystals. The solid state intercalation is reversible, and Cu can also be deintercalated from the Bi2Se3 and Bi2Te3 nanocrystals upon heating and utilized in other reactions on the solid substrate. The extent of intercalation and deintercalation, however, depends on any interaction between the intercalant and host nanocrystals in response to heating. The concepts explored here hold promise for future development of novel solid state based energy storage nanodevices or possibly NC-based devices whose properties and/or function could be reversibly modulated through a combination of solid state CE and intercalation/deintercalation.