Independent control of the shape and composition of ionic nanocrystals through sequential cation exchange reactions
Size- and shape-controlled nanocrystal growth is intensely researched for applications including electro-optic, catalytic, and medical devices. Chemical transformations such as cation exchange overcome the limitation of traditional colloidal synthesis, where the nanocrystal shape often reflects the inherent symmetry of the underlying lattice. Here we show that nanocrystals, with established synthetic protocols for high monodispersity, can be templates for independent composition control. Specifically, controlled interconversion between wurtzite CdS, chalcocite Cu2S, and rock salt PbS occurs while preserving the anisotropic dimensions unique to the as-synthesized materials. Sequential exchange reactions between the three sulfide compositions are driven by the disparate solubilites of the metal ion exchange pair in specific coordinating molecules. Starting with CdS, highly anisotropic PbS nanorods are created, which serve as an important material for studying strong 2-dimensional quantum confinement, as well as for optoelectronic applications. Furthermore, interesting nanoheterostructures of CdS|PbS are obtained by precise control over ion insertion and removal.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- Materials Sciences Division
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 974549
- Report Number(s):
- LBNL-2367E
- Journal Information:
- Nature Chemistry, Journal Name: Nature Chemistry
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
CATIONS
CONFINEMENT
DIMENSIONS
ION EXCHANGE
PbS
lead sulfide
nanorods
cation exchange
copper sulfide
Cu2S
CdS
Cadmium sulfide
nanocrystal
quantum dots
REMOVAL
SALT DEPOSITS
SHAPE
SULFIDES
SYMMETRY
SYNTHESIS
TRANSFORMATIONS