title: High temperature continuous flow synthesis of CdSe/CdS/ZnS, CdS/ZnS, and CdSeS/ZnS nanocrystals.
abstract: Continuous flow reactors show great promise for large-scale synthesis of quantum dots. Here, we discuss results for the synthesis of multi-layered Cd-based hybrid nanocrystals - CdSe/CdS/ZnS, CdS/ZnS, and CdSeS/ZnS - in a continuous flow reactor. The simple reactor design and liquid-phase chemistry obviate the need for preheating or in-line mixing, and the chosen reactor dimensions and operating conditions allow for high flow rates (∼10 mL min(-1)). Additionally, the simple reactor design is well suited for scale-up. The CdSe/CdS/ZnS particles synthesized at elevated temperatures in the reactor exhibit quantum yields of over 60% at longer wavelengths (red region). The shell growth for these particles is conducted without the need for complex dropwise addition or SILAR shell growth procedures used in batch reactors. CdS-based particles were shown to have a higher performance when using octadecene-S instead of TOP-S, which improved the quality of shell growth. In addition, stoichiometric synthesis of the alternate CdSeS/ZnS alloy particles was conducted, removing the need for a large excess of S to offset the lower S reactivity. CdSeS/ZnS alloy nanoparticles exhibit quantum yields of about 50% in the intermediate wavelength range (500-600 nm).
authors.affiliation: Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Ave, Urbana, IL 61801, USA. kenis@illinois.edu.
authors.forename: Matt S
authors.initials: MS
authors.lastname: Naughton
authors.forename: Vivek
authors.initials: V
authors.lastname: Kumar
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Bonita
authors.forename: Kishori
authors.initials: K
authors.lastname: Deshpande
authors.forename: Paul J A
authors.initials: PJ
authors.lastname: Kenis