Abé, Sofie

Capek, Richard K

Cottenier, Stefaan

De Nolf, Kim

Hens, Zeger

Jang, Youngjin

Lifshitz, Efrat

Sluydts, Michael

Ghent University Academic Bibliography

PHOSPHINE OXIDE CHAIN LENGTH DIFFUSION COEFFICIENT D CONCLUSION Acknowledgements References Controlling the Nano-particle Size by Manipulating  the Diffusion Coefficient of the Solute (1) Abe, S.; Capek, R. K.; De Geyter, B.; Hens, Z. ACS Nano 2013, 7, 943–949. This research has been funded by FWO-Vlaanderen (G.0760.12) 1 Physics and Chemistry of Nanostructures, Ghent University, Belgium 2 Center for Nano- and Biophotonics, Ghent University , Belgium 3 Technion, Israel 4 Center for Molecular Modeling, Ghent University , Belgium Kim De Nolf1,2 Ι Richard K. Capek3 Ι Sofie Abe1,2 Ι Michaël Sluydts4 Ι Youngjin Jang3 Ι Stefaan Cottenier4 Ι Efrat Lifshitz3 Ι Zeger Hens1,2 𝐽𝑁 =2𝐷𝜈05/3𝑒𝑥𝑝 −16 𝜋𝛾3𝜈023 𝑘𝐵𝑇 3 ln 𝑆 2 & structural analysis unit For two different CdSe nanocrystal syntheses, we consistently find that longer chain carboxylic acids result in smaller nanocrystals with improved size dispersions.  With two different CdSe nanocrystal syntheses, we find that longer chain carboxylic acids result in smaller nanocrystals with improved size dispersions.  This size tuning is due to a change in the diffusion coefficient and the solubility of the solute.  In line with the weak coordination of CdSe nanocrystals by amines, no influence of the chain length on the nanocrystals is found.  The size tuning brought about by phosphine oxides can be attributed to a solubility change.  The ligand chain length provides a practical handle to optimize the outcome of a hot injection synthesis in terms of size and size dispersion and can be used to probe the interaction between ligands and the actual solute. MONOMER SOLUBILITY [M]0  CARBOXYLIC ACIDS: LONGER CHAIN ACIDS  = SMALLER NANOCRYSTALS → No influence of chain length on QDs → No influence of amines on diffusion coefficient of CdOA2 → Weak coordination of CdSe QDs by amines AMINE CHAIN LENGTH 𝐽𝐺 = 𝐷𝜈0𝑁𝐴 𝑀 0𝑆 − 𝑒𝑥𝑝2𝛾𝜈0𝑟𝑘𝐵𝑇𝑟 +𝐷 𝑀 0𝑘𝑑∞ 𝑒𝑥𝑝 𝛼2𝛾𝜈0𝑟𝑘𝐵𝑇 NUCLEATION AND GROWTH reaction screening with reaction simulations, we demonstrate that this size tuning is due to a change in the diffusion coefficient and the solubility of the solute. The relation between size tuning by the ligand chain length and the coordination of the solute by the ligands is further explored by expanding the study to amines and phosphine oxides. INTRODUCTION Colloidal semiconductor nanocrystals or quantum dots (QDs) are typically produced via a hot injection synthesis (HIS). For QDs to be implemented in a broad range of applications, a precise control over their size is essential. We show that efficient size tuning at high reaction yield is possible by changing the chain length of the  carboxylic  acid.  By  combining  an  extended  experimental  → Minor effect on dNC and σd for low concentrations.  → Resembles amines  → Effect rather due to a change of the solubility of the monomer and not its diffusion coefficient. Amount of oleic acid (OAc) ↑ in an OAc synthesis: → Monomer solubility [M]0 ↑ (1)  → dNC and σd ↑  Amount of oleic acid (OAc) ↑ in a DAc synthesis: → dNC and σd ↓ Changing the ligand chain length affects other parameters, next to the solute solubility, that have an influence on the balance between the nucleation and growth rate. 𝐷𝑟𝑜𝑑 =𝑘𝐵𝑇6 𝜋𝜂𝒂ln2𝒂𝒃 → D of carboxylic acids and CdOA2 were measured with NMR → Correlation between D and #C of the carboxylic acids → Size(CdOA2) ≈ 2. size(OA)       and 2. DCdOA2 ≈ DOA 

Controlling the nano-particle size by manipulating the diffusion coefficient of the solute

https://biblio.ugent.be/publication/7072018/file/7072029

Controlling the nano-particle size by manipulating the diffusion coefficient of the solute

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