The electronic and optical properties of colloidal quantum dots,
including the wavelengths of light that they can absorb and emit,
depend on the size of the quantum dots. These properties have
been exploited in a number of applications including optical
detection1–3, solar energy harvesting4,5 and biological research6,7.
Here, we report the self-assembly of quantum dot complexes
using cadmium telluride nanocrystals capped with specific
sequences of DNA. Quantum dots with between one and five
DNA-based binding sites are synthesized and then used as building
blocks to create a variety of rationally designed assemblies,
including cross-shaped complexes containing three different
types of dots. The structure of the complexes is confirmed
with transmission electron microscopy, and photophysical
studies are used to quantify energy transfer among the constituent
components. Through changes in pH, the conformation of the
complexes can also be reversibly switched, turning on and off the
transfer of energy between the constituent quantum dots.DNA-based programming of quantum dot valency, self-assembly and luminescence .
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