Steady-State Synthesis of Colloidal Metal Nanocrystals

Despite remarkable progress, colloidal synthesis of metal nanocrystal is still far away from reaching the goal for robust, reproducible, and scalable production. Even with the adoption of seed-mediated growth, the synthesis can still be complicated by issues such as self-nucleation, galvanic replacement, stochastic symmetry reduction, and unwanted compositional variation. All these issues can be addressed by switching to steady-state synthesis characterized by a slow, constant, and tightly controlled reduction rate. Steady-state synthesis can be achieved by adding one reactant dropwise while using the other reactant in large excess, but this method is not suitable for scale-up production in a continuous flow reactor. There is a pressing need to develop alternative methods capable of establishing the steady-state kinetics characteristic of dropwise addition while introducing both reactants by one-shot injection. In this Perspective, we discuss a number of methods that allow for both one-shot injection and steady-state synthesis.