Blue Quantum Dots by Microemulsion Oxidation

In an Inorganic Chemistry publication back in March 2008, Yadong Li's group at Tsingua Univ. synthesized CdSe nanoparticles that were small enough to fluoresce blue. Because of quantum confinement, nanoparticles (specifically quantum dots) fluoresce at shorter wavelengths with smaller radii. To synthesize quantum dots with radii this small is difficult; they must be smaller than 2 nm.



The method they employed was to first create nanoparticles by a microemulsion route, then mildly oxidize the nanoparticles to reduce them into smaller particles. The pretty picture you see above shows the nanoparticles after microemulsion on the left, then after further oxidation on the right.This was an effective route and they were able to create sufficiently small nanoparticles. I actually did a lengthy paper and presentation on the dynamics of nanoparticle synthesis by microemulsion this semester, so I enjoyed coming across a paper that employed it. It's advantageous because you can limit the nanoparticle size effectively.



The diagram above is the basic scheme for microemulsion synthesis. Basically, each microemulsion contains a reactant of the synthesis, and when they are forced together (in a reactor) exchange occurs and the reactants combine. Because there is limited reactant in each droplet, the size of the nanoparticle is controllable, and the size of the droplet regulates the size as well. The image is from this paper.

Anyhow, I enjoy the idea of using the sun in synthesis, but it kind of sucks for research labs that don't get too much of it. I don't see any problems with the paper - I'm pretty impressed. Maybe someday I'll make nanoparticles by a non-single source precursor method and will employ a microemulsion technique.

Liu, L., Peng, Q., Li, Y. (2008). An Effective Oxidation Route to Blue Emission CdSe Quantum Dots. Inorganic Chemistry, 47(8), 3182-3187. DOI: 10.1021/ic702203c

Godspeed.



This posted tagged as: journals, science