Extended Nucleation and Superfocusing in Colloidal Semiconductor Nanocrystal Synthesis
Prins, P. Tim; Montanarella, Federico; Dümbgen, Kim; Justo, Yolanda; Van Der Bok, Johanna C.; Hinterding, Stijn O.M.; Geuchies, Jaco J.; Maes, Jorick; De Nolf, Kim; Deelen, Sander; Meijer, Hans; Zinn, Thomas; Petukhov, Andrei V.; Rabouw, Freddy T.; De Mello Donega, Celso; Vanmaekelbergh, Daniel; Hens, Zeger
(2021) Nano Letters, volume 21, issue 6, pp. 2487 - 2496
(Article)
Abstract
Hot-injection synthesis is renowned for producing semiconductor nanocolloids with superb size dispersions. Burst nucleation and diffusion-controlled size focusing during growth have been invoked to rationalize this characteristic yet experimental evidence supporting the pertinence of these concepts is scant. By monitoring a CdSe synthesis in-situ with X-ray scattering, we find that
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nucleation is an extended event that coincides with growth during 15-20% of the reaction time. Moreover, we show that size focusing outpaces predictions of diffusion-limited growth. This observation indicates that nanocrystal growth is dictated by the surface reactivity, which drops sharply for larger nanocrystals. Kinetic reaction simulations confirm that this so-called superfocusing can lengthen the nucleation period and promote size focusing. The finding that narrow size dispersions can emerge from the counteracting effects of extended nucleation and reaction-limited size focusing ushers in an evidence-based perspective that turns hot injection into a rational scheme to produce monodisperse semiconductor nanocolloids.
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Keywords: in-situ analysis, monodisperse, nanocolloids, nucleation and growth, photoluminescence, quantum dots, Taverne, Bioengineering, General Chemistry, General Materials Science, Condensed Matter Physics, Mechanical Engineering
ISSN: 1530-6984
Publisher: American Chemical Society
Note: Funding Information: Z.H. acknowledges support by FWO-Vlaanderen (research projects G0F0920N and G0B2921N) and Ghent University (BOF-GOA 01G01019). K.D. acknowledges FWO-Vlaanderen for a scholarship. Z.H., D.V.M., and F.M. acknowledge support by the European Commission via the Marie-Sklodowska Curie Action Phonsi (H2020-MSCA-ITN-642656). D.V., C.D.M.D., and F.T.R. acknowledge support by The Netherlands Organization for Scientific Research (NWO; grants 14614 “Q-Lumicon”, Veni 722.017.002) and The Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC). J.J.G. acknowledges financial support from the joint UU and ESRF Graduate Program. The authors thank the ESRF for providing beam time (experiment HC-3725), Jacques Gorini and Narayanan Theyencheri for assistance during beam time, and Liheng Wu and Matteo Cargnello for fruitful discussions. Publisher Copyright: ©
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