Shape-Controlled Synthesis of CdSe Nanocrystals via a Programmed Microfluidic Process

Semiconductor nanocrystals (NCs) exhibit excellent electronic and optical properties due to their shape-, size-, and defect-dependent quantum-confinement effect. Controlling the formation kinetics for tunable size, shape, and defect has become more and more important for desired optoelectronic properties but is very challenging. In our work, we extend our previous hybrid microfluidic-batch process in the size-, shape-, and crystallinity-controlled synthesis of semiconductor NCs using CdSe NCs as model materials by precisely regulating reaction temperatures from 150 to 300 °C at a flow rate of 0.6 mL/min. Highly crystalline CdSe NCs with controlled shapes (vague angular, tripodia, irregular polygon, and sphere) and sizes (from 2.57 to 4.31 nm) were successfully synthesized, exhibiting unique UV−vis absorbance and photoluminescence.