In Situ Optical and X-ray Spectroscopy Reveals Evolution toward Mature CdSe Nanoplatelets by Synergetic Action of Myristate and Acetate Ligands

Johanna C. van der Bok, P. Tim Prins, Federico Montanarella, D. Nicolette Maaskant, Floor A. Brzesowsky, Maaike M. van der Sluijs, Bastiaan B. V. Salzmann, Freddy T. Rabouw, Andrei V. Petukhov, Celso De Mello Donega, Daniel Vanmaekelbergh, Andries Meijerink

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The growth of two-dimensional platelets of the CdX family (X = S, Se, or Te) in an organic solvent requires the presence of both long- and short-chain ligands. This results in nanoplatelets of atomically precise thickness and long-chain ligand-stabilized Cd top and bottom surfaces. The platelets show a bright and spectrally pure luminescence. Despite the enormous interest in CdX platelets for optoelectronics, the growth mechanism is not fully understood. Riedinger et al. studied the reaction without a solvent and showed the favorable role for short-chain carboxylates for growth in two dimensions. Their model, based on the total energy of island nucleation, shows favored side facet growth versus growth on the top and bottom surfaces. However, several aspects of the synthesis under realistic conditions are not yet understood: Why are both short- and long-chain ligands required to obtain platelets? Why does the synthesis result in both isotropic nanocrystals and platelets? At which stage of the reaction is there bifurcation between isotropic and 2D growth? Here, we report an in situ study of the CdSe nanoplatelet reaction under practical synthesis conditions. We show that without short-chain ligands, both isotropic and mini-nanoplatelets form in the early stage of the process. However, most remaining precursors are consumed in isotropic growth. Addition of acetate induces a dramatic shift toward nearly exclusive 2D growth of already existing mini-nanoplatelets. Hence, although myristate stabilizes mini-nanoplatelets, mature nanoplatelets only grow by a subtle interplay between myristate and acetate, the latter catalyzes fast lateral growth of the side facets of the mini-nanoplatelets.

Original languageEnglish
Pages (from-to)8096-8105
Number of pages10
JournalJournal of the American Chemical Society
Volume144
Issue number18
DOIs
Publication statusPublished - 11 May 2022

Keywords

  • Cadmium
  • Scattering
  • Cadmium selenide
  • Organic Compounds
  • Quantum dots

Fingerprint

Dive into the research topics of 'In Situ Optical and X-ray Spectroscopy Reveals Evolution toward Mature CdSe Nanoplatelets by Synergetic Action of Myristate and Acetate Ligands'. Together they form a unique fingerprint.

Cite this