Identifying reactive organo-selenium precursors in the synthesis of CdSe nanoplatelets

Riedinger, Andreas; Mule, Aniket S.; Knüsel, Philippe N.; Ott, Florian D.; Rossinelli, Aurelio A.; Norris, David J.

doi:10.1039/c8cc06326e

Cited by 20 publications

(37 citation statements)

References 28 publications

(36 reference statements)

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“…[5][6][7] CdSe NPLs can by synthesized by colloidal methods so that every particle in the ensemble has exactly the same thickness of an integer number of atomic layers, while being extended in the other two dimensions. 8,9 As a result, every NPL experiences the same level of quantum confinement (across their thickness) and the ensemble and single particle spectral properties are nearly identical. 10 The absence of inhomogeneous broadening leads to exceptionally narrow line widths.…”

Section: Introductionmentioning

confidence: 99%

Water-dispersed semiconductor nanoplatelets with high fluorescence brightness, chemical and colloidal stability

et al. 2020

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Section: Introductionmentioning

confidence: 99%

Water-dispersed semiconductor nanoplatelets with high fluorescence brightness, chemical and colloidal stability

et al. 2020

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“…To achieve continuous tunability of absorption and emission spectra over the whole blue-green region we synthesized a series of alloyed CdSexS1-x NPLs with varying ratios of Se and S, as In this work, we mitigate the reactivity difference by employing highly reactive stearoyl selenide and sulfide, which were shown to be chalcogen intermediates in the synthesis of NPLs. 39 Regardless of their high reactivity, unlike other active chalcogen sources traditionally used in NCs synthesis (e.g. trimethylsilyl-or alkylphosphine-chalcogen complexes), they can be conveniently processed and handled in ambient atmosphere without any significant effect on the reaction outcome.…”

Section: Resultsmentioning

confidence: 99%

CdSexS1-x Alloyed Nanoplatelets with Continuously Tunable Blue-Green Emission

Antanovich

Yang

Erwin

et al. 2022

Preprint

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Cadmium chalcogenide nanoplatelets (NPLs) are established as promising materials for a wide variety of optoelectronic applications due to their properties surpassing in many aspects counterpart nanocrystals (NCs) with other shapes. Most of these features arise from strong quantum confinement in the direction of thickness which can be tuned with precision down to one monolayer. However, atomic smoothness of their basal planes and hence the ability to change the NPL thickness only in discrete steps prevent precise tuning of absorption and photoluminescence spectra unlike in the case of quantum dots. Preparation of alloyed NCs provides a potential solution to this problem, but it is complicated by the different reactivity of chalcogenide sources, which becomes even more restrictive in the case of NPLs, since they are more sensitive to alterations of reaction conditions. In this work, we overcome this obstacle by employing highly reactive stearoyl sulfide and selenide as chalcogen sources, which enable straightforward variation of the NPLs composition and thickness by changing the ratio of chalcogen precursors and reaction temperature, respectively. Alloyed CdSexS1-x NPLs obtained exhibit tunable absorption and photoluminescence bands covering the blue-green region from 380 to 520 nm with bright band-edge emission and quantum yields of ~30–50 % due to their relatively small lateral size enabled by a much finer control of the lateral growth.

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“…The fast generation of CdSe monomers from the reaction of bis(acyl) selenides (sulfides) and cadmium carboxylates was previously utilized to form CdSe (CdS) nanoplatelets. 45,46 To assess the importance of highly reactive Se precursors for MSNCs, we repeated our reaction with two less-reactive Se precursors that are often exploited in nanocrystal syntheses, elemental Se and trioctylphosphine selenide (Figure S8). Neither produced MSNCs.…”

Section: Resultsmentioning

confidence: 99%

Unraveling the Growth Mechanism of Magic-Sized Semiconductor Nanocrystals

Mule¹,

Mazzotti²,

Rossinelli³

et al. 2020

Preprint

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Magic-sized clusters (MSCs) of semiconductor are typically defined as specific molecular-scale arrangements of atoms that exhibit enhanced stability. They often grow in discrete jumps, creating a series of crystallites, without the appearance of intermediate sizes. However, despite their long history, the mechanism behind their special stability and growth remains poorly understood. This is particularly true considering experiments that have shown discrete evolution of MSCs to sizes well beyond the “cluster” regime and into the size range of colloidal quantum dots. Here, we study the growth of these larger magic-sized CdSe nanocrystals to unravel the underlying growth mechanism. We first introduce a synthetic protocol that yields a series of nine magic-sized nanocrystals of increasing size. By investigating these crystallites, we obtain important clues about the mechanism. We then develop a microscopic model that uses classical nucleation theory to determine kinetic barriers and simulate the growth. We show that magic-sized nanocrystals are consistent with a series of zinc-blende crystallites that grow layer by layer under surface-reaction-limited conditions. They have a tetrahedral shape, which is preserved when a monolayer is added to any of its four identical facets, leading to a series of discrete nanocrystals with special stability. Our analysis also identifies strong similarities with the growth of semiconductor nanoplatelets, which we then exploit to increase further the size range of our magic-sized nanocrystals. Although we focus here on CdSe, these results reveal a fundamental growth mechanism that can provide a different approach to nearly monodisperse nanocrystals.

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Identifying reactive organo-selenium precursors in the synthesis of CdSe nanoplatelets

Abstract: Bis(acyl) selenides are identified as selenium precursors that can provide additional control over the synthesis of CdSe nanoplatelets.

Cited by 20 publications

References 28 publications

Water-dispersed semiconductor nanoplatelets with high fluorescence brightness, chemical and colloidal stability

Water-dispersed semiconductor nanoplatelets with high fluorescence brightness, chemical and colloidal stability

CdSexS1-x Alloyed Nanoplatelets with Continuously Tunable Blue-Green Emission

Unraveling the Growth Mechanism of Magic-Sized Semiconductor Nanocrystals

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