Strain effects on optical properties of tetrapod-shaped CdTe/CdS core–shell nanocrystals

Ya, Yao; Kuroda, Takashi; Dirin, Dmitry N.; Sokolikova, Maria; Vasiliev, R. B.

doi:10.1016/j.spmi.2014.10.017

Cited by 4 publications

(4 citation statements)

References 44 publications

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“…Earlier similar effect was shown for spherical and further for tetrapod-like core−shell CdTe/CdS nanocrystals. 48,49 As can be seen from Figure 5b, strain contribution decreases with increasing thickness of CdTe NSs, which is consistent with results for tetrapod-like strained core−shell CdTe/CdS nano- crystals. 49 The substantial broadening of exciton bands may be attributed to an increase of the exciton−phonon coupling shown for core/shell CdSe/CdS 39 or alloyed CdS x Se 1−x 19 nanoplatelets.…”

Section: ■ Results and Discussionsupporting

confidence: 86%

“…Higher exciton band energy for thiol-covered CdTe NSs compared with as-grown CdTe with the equal overall thickness may indicate strain effect contribution because energy gap increases with applied compressive force considered for CdTe core layer. Earlier similar effect was shown for spherical and further for tetrapod-like core–shell CdTe/CdS nanocrystals. , As can be seen from Figure b, strain contribution decreases with increasing thickness of CdTe NSs, which is consistent with results for tetrapod-like strained core–shell CdTe/CdS nanocrystals . The substantial broadening of exciton bands may be attributed to an increase of the exciton–phonon coupling shown for core/shell CdSe/CdS or alloyed CdS x Se 1– x nanoplatelets.…”

Section: Results and Discussionsupporting

confidence: 86%

“…This effect agreed with strain distribution along misfit strained core−shell nanowire. 49,53 For strainrelated folding the radii should depend on the relation of strain and NS thickness. Thicker sheet corresponds to higher radii, which was supported by estimation of the radii of scrolling in dependence on sheet thickness with the use of Timoshenko equation (see details in Supporting Information).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Spontaneous Folding of CdTe Nanosheets Induced by Ligand Exchange

Vasiliev¹,

Lazareva²,

Karlova³

et al. 2018

Chem. Mater.

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Two-dimensional (2D) semiconductors exhibit unique electronic and optical properties arising from the atomic-scale thickness and two-dimensional electronic structure. However, it is usually limited by an intrinsically flat morphology of 2D materials. Here, we report an effect of spontaneous folding of quasi-2D CdTe nanosheets stimulated by ligand exchange. We show that initially flat CdTe nanosheets with 100−200 nm lateral size and 5−6 ML thickness are uniformly rolled up when oleic acid is replaced by thiol-containing ligands. Detailed study shows nanosheet folding along the [110] direction forming multiwall scroll-like structures with the diameter being dependent on sheet thickness. A pronounced red shift of the exciton transitions of CdTe nanosheets is found due to thickness increase and strain appearance under thiol attachment. The folding mechanism is likely related to misfit strain at CdTe (001) basal planes as ultrathin CdS layer is formed. Possibility to precisely tune the nanostructure shape simply by ligand-induced strain can evolve into new synthetic strategies to control a spatial morphology of 2D materials.

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Section: ■ Results and Discussionsupporting

confidence: 86%

Section: Results and Discussionsupporting

confidence: 86%

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Spontaneous Folding of CdTe Nanosheets Induced by Ligand Exchange

Vasiliev¹,

Lazareva²,

Karlova³

et al. 2018

Chem. Mater.

Self Cite

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“…Such strain can induce lattice distortion leading to change in the bandgap of the material. For example, the tetrahedral symmetry of the CdTe/CdS core/shell tetrapod system combined with strain effects can lead to more efficient charge separation compared to type-II spherical NCs . Atomic force microscopy (AFM) reveals that the strain has a considerable importance at the junction point (core/shell interface) of the tetrapod. , Under the AFM, when the load is applied, the mechanical response of the CdTe tetrapod is investigated using force–volume (FV) mapping such that the force–distance curve is taken over the top of the vertical arm.…”

Section: Properties Of Metal Chalcogenide Semiconductor Tetrapod Nano...mentioning

confidence: 99%

Recent Progress on Metal Chalcogenide Semiconductor Tetrapod-Shaped Colloidal Nanocrystals and their Applications in Optoelectronics

2019

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Mastery over the shape of a colloidal nanocrystal has proven to be a powerful tool to control its properties and broaden the range of applications. This is particularly relevant in the case of branched semiconductor nanocrystals, which are of special interest due to their unique optoelectronic properties. An archetypal example of a branched shape in nanocrystals is represented by particles made of a core from which four arms/pods are grown, so-called tetrapods. Many research groups have investigated these structures, driven by their potential use in optics, in which their geometry helps to efficiently capture photons from a wide range of incident angles. In addition, tetrapods have increasingly attracted much attention because of their ability to self-assemble into, for instance, percolating networks, providing an efficient way to create electronic pathways in devices that rely upon charge transport. This has stimulated in part the development of synthetic protocols to control the growth of uniform arms in particles of different sizes and, thus, to tune their functionalities, expanding the configurations that can be built via self-assembly. Recently, researchers have designed several innovative approaches for the synthesis of tetrapods, which include the combination of different material components in the same particle to achieve multiple properties. In this review, we will focus on metal chalcogenide semiconductor tetrapod-shaped nanocrystals and summarize recent progress on their synthesis methods, highlighting the various routes that aim to fabricate hybrid tetrapod nanostructures. We will examine the fundamental optoelectronic properties of tetrapod-shaped nanocrystals and provide an up-to-date overview of the strategies developed for their self-organization into different architectures. Finally, we will review their applications in photovoltaics, optoelectronics, and mechanical devices.

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