Chemical Considerations for Colloidal Nanocrystal Synthesis

We take here the perspective of a nanochemist on the field of colloidal nanocrystals, focusing specifically on nanocrystal synthesis. Considering the three components of a colloidal synthesis, we discuss the chemistry that occurs with precursors, ligands, and solvents. Insight into the coordination chemistry and the organic chemistry of nanocrystal syntheses brings us one step closer to a retro-synthetic analysis of a nanocrystal reaction. We also reflect on different crystallization mechanisms (either under thermodynamic or kinetic control). We consider the possibility that the different models are simply describing different experimental conditions and are not fundamentally at odds with one another. However, we do critically evaluate the use of the terms monomer and burst nucleation. Finally, we discuss good chemical practices for a nanochemist, and we try to define nanocrystal purity. This perspective will hopefully inspire researchers in colloidal nanoscience to think more about chemical equations, consider reaction by-products, and come together as a field to agree on standard reporting practices for colloidal nanocrystals.