Engineering Bicolor Emission in 2D Core/Crown CdSe/CdSe1–xTex Nanoplatelet Heterostructures Using Band-Offset Tuning

Marion Dufour^a, Violette Steinmetz^b, Eva Izquierdo^a, Thomas Pons^a, Nicolas Lequeux^a, Emmanuel Lhuillier^b, Laurent Legrand^b, Maria Chamarro^b, Thierry Barisien^b, Sandrine Ithurria^a

^aLaboratoire de Physique et d’Etude des Matériaux, PSL Research University, CNRS UMR 8213, UPMC Sorbonne Université, ESPCI Paris, Rue Vauquelin, 10, Paris, France

^bSorbonne Universités, UPMC Univ Paris 06, UMR CNRS 7588, Institut des Nanosciences de Paris (INSP), Place Jussieu, 4, Paris, France

Materials for Sustainable Development Conference (MATSUS)
Proceedings of nanoGe Fall Meeting 2018 (NFM18)

S6 Solution-based Two-dimensional Nanomaterials Sol2D

Torremolinos, Spain, 2018 October 22nd - 26th

Organizers: Christophe Delerue, Sandrine Ithurria and Christian Klinke

Oral, Marion Dufour, presentation 006
DOI: https://doi.org/10.29363/nanoge.nfm.2018.006
Publication date: 6th July 2018

Colloidal 2D hetero-nanoplatelets offer new possibilities in terms of heterostructure engineering. The growth can be done either in the confined direction² or perpendicular to the confined direction³. This second type of heterostruture is called core/crown. It gives the opportunity to tune the composition and the lateral dimensions of each material while keeping a constant confinement (thickness). We show that synthesizing CdSe/CdSe_1-xTe_x core/crown nanoplatelets with the right composition and lateral extension enables bicolor emission at the single-nanoparticle level. The first transition at low energy comes from core/crown interface recombination (Xint) and is comparable to the one observed in CdSe/CdTe⁴. The second one, at higher energy, originates from a direct recombination of the exciton in the crown. It is only visible for Te compositions x close to 60% and more likely occurs as the crown dimensions increase. This bicolor emission results from a competition between the conduction band offset that attracts the electron in the core material and the exciton binding energy that retains it in the crown. For 60% of Te those energies are similar (~250meV) and allows the coexistence of the two recombination processes.

(1) Dufour, M.; Steinmetz, V.; Izquierdo, E.; Pons, T.; Lequeux, N.; Lhuillier, E.; Legrand, L.; Chamarro, M.; Barisien, T.; Ithurria, S. Engineering Bicolor Emission in 2D Core/crown CdSe/CdSe1-xTex nanoplatelet Heterostructures Using Band-Offset Tuning. J. Phys. Chem. C 2017, 121, 24816–24823.

(2) Ithurria, S.; Talapin, D. V. Colloidal Atomic Layer Deposition (c-ALD) Using Self-Limiting Reactions at Nanocrystal Surface Coupled to Phase Transfer between Polar and Nonpolar Media. J. Am. Chem. Soc. 2012, 134, 18585–18590.

(3) Tessier, D.; Spinicelli, P.; Dupont, D.; Patriarche, G.; Ithurria, S.; Dubertret, B. Efficient ExcitonConcentrators Built from Colloidal Core/Crown CdSe/CdS Semiconductor Nanoplatelets. 2014.

(4) Pedetti, S.; Ithurria, S.; Heuclin, H.; Patriarche, G.; Dubertret, B. Type-II CdSe/CdTe Core/crown Semiconductor Nanoplatelets. J. Am. Chem. Soc. 2014, 136, 16430–16438.

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