Synthesis of Semiconductor Nanoparticles in a Continuous Flow Reactor

D. Ness, J. Niehaus, V-H Tran, H. Weller
CAN GmbH, DE

Keywords: quantum dots, continuous flow synthesis, core/shell/shell, nanoparticles, CdSe

Summary:

Cd-based fluorescent nanoparticles – Quantum Dots (QDs) - found a great acceptance in processes for monitoring and targeting, e.g. in light emitting devices or lasers as well as marker for biological systems like proteins or DNA. The common strategy for the synthesis of QDs is based on a batch process called hot-injection method. This procedure requires high nucleation temperature, a fast cooling step to the growth temperature and immediate and complete mixing after the injection. Up-scaling the synthesis is difficult in this manner and can lead to slightly different properties each time the reaction has been performed. This issue can be addressed by performing the synthesis in a continuous flow reactor. Within this paper we report the use of a continuous flow reactor for the production of more complex systems based on CdSe quantum dots. There are some essential benefits using our reactor compared to the ones from literature: the synthesis of core, core/shell as well as core/shell/shell structures can be achieved, nucleation and growth are spatially separated to exactly mimic the traditional hot-injection method and an integrated spectroscopic unit analyzes particle quality online.