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- Title
Continuous-Flow Synthesis of CdSe Quantum Dots: A Size-Tunable and Scalable Approach.
- Authors
Mirhosseini Moghaddam, Mojtaba; Baghbanzadeh, Mostafa; Sadeghpour, Amin; Glatter, Otto; Kappe, C. Oliver
- Abstract
In recent years, continuous-flow/microreactor processing for the preparation of colloidal nanocrystals has received considerable attention. The intrinsic advantages of microfluidic reactors have opened new opportunities for the size-controlled synthesis of nanocrystals either in the laboratory or on a large scale. Herein, an experimentally simple protocol for the size-tunable continuous-flow synthesis of rather monodisperse CdSe quantum dots (QDs) is presented. CdSe QDs are manufactured by using cadmium oleate as cadmium source, selenium dioxide as selenium precursor, and 1-octadecene as solvent. Exploiting selenium dioxide as selenium source and 1-octadecene as solvent allows execution of the complete process in open air without any requirement for air-free manipulations using a glove box or Schlenk line. Continuous-flow processing is performed with a stainless steel coil of 1.0 mm inner diameter pumping the combined precursor solution through the reactor by applying a standard HPLC pump. The effect of different reaction parameters, such as temperature, residence time, and flow rate, on the properties of the resulting CdSe QDs was investigated. A temperature increase from 240 to 260 °C or an extension of the residence time from 2 to 20 min affords larger nanocrystals (range 3-6 nm) whereas the size distribution does not change significantly. Longer reaction times and higher temperatures result in QDs with lower quantum yields (range 11-28 %). The quality of the synthesized CdSe QDs was confirmed by UV/Vis and photoluminescence spectroscopy, small-angle X-ray scattering, and high-resolution transmission electron microscopy. Finally, the potential of this protocol for large-scale manufacturing was evaluated and by operating the continuous-flow process for 87 min it was possible to produce 167 mg of CdSe QDs (with a mean diameter of 4 nm) with a quantum yield of 28 %.
- Subjects
CONTINUOUS flow reactors; QUANTUM dots; NANOCRYSTAL synthesis; GLOVE boxes (Safety devices); HIGH performance liquid chromatography; PHOTOLUMINESCENCE; X-ray scattering
- Publication
Chemistry - A European Journal, 2013, Vol 19, Issue 35, p11629
- ISSN
0947-6539
- Publication type
Article
- DOI
10.1002/chem.201301117