An investigation of heating rate effects on particle size and concentration: instruction for scale-up

Abstract

Increasing the synthesis scale is one of the most important issues in nanocrystal synthesis. The main difference between small and large reactors is the thermal transfer rate, which has been reported to have great effects on particle nucleation and growth. According to this viewpoint, the heating rate effects should be studied before designing the scale-up process. In this paper, CdSe quantum dots synthesis was used as a model to investigate the heating rate effects in a microreactor system capable of precisely controlling the temperature and heating rate. The results showed a high dependence of heating rate effects on synthesis parameters. The effects of nucleation and growth kinetics were also investigated. Test experiments to demonstrate the possibility of a scale-up were conducted and results showed that products synthesized by a batch reactor were comparable with microreactor products. Further investigation indicated that heating rate could affect the growth kinetics and subsequently affect the final products at 10% and 20% DDA. Based on these results, the application of a large reactor for large scale synthesis can be considered possible, otherwise a larger reactor cannot be applied and precise heating rate controlling is deemed necessary.