Acid Dissociation of 3-Mercaptopropionic Acid Coated CdSe–CdS/Cd0.5Zn0.5S/ZnS Core–Multishell Quantum Dot and Strong Ionic Interaction with Ca2+ Ion

Shambetova, Nestan; Chen, Yun; Xu, Hao; Li, Li; Solandt, Johan; Zhou, Yuhua; Wang, J.; Su, Haibin; Brismar, Hjalmar; Fu, Ying

doi:10.1021/acs.jpcc.5b11023

Cited by 16 publications

(14 citation statements)

References 50 publications

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“…At these pHs, the carboxylic acid group on the MPA ligand is negative. However, the presence of divalent cations such as Ca 2+ are likely to partially neutralize the negative charge on the COO − group, 48 even more so than monovalent cations especially when present with Mg 2+ , 49 as was the case in MHRW. At pH ~5, CL4 is zwitterionic, yet in MHRW, pH 8, the CdSe-CL4 was significantly more negative than in both DIW and saline.…”

Section: Resultsmentioning

confidence: 99%

Ligands and media impact interactions between engineered nanomaterials and clay minerals

et al. 2019

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The exponential growth in technologies incorporating engineered nanomaterials (ENMs) requires plans to handle waste ENM disposal and accidental environmental release throughout the material life cycle. These scenarios motivate efforts to quantify and model ENM interactions with diverse background particles and solubilized chemical species in a variety of environmental systems. In this study, quantum dot (QD) nanoparticles and clay minerals were mixed in a range of water chemistries in order to develop simple assays to predict aggregation trends. CdSe QDs were used as a model ENM functionalized with either negatively charged or zwitterionic small molecule ligand coatings, while clays were chosen as an environmentally relevant sorbent given their potential as an economical water treatment technology and ubiquitous presence in nature. In our unbuffered experimental systems, clay type impacted pH, which resulted in a change in zwitterionic ligand speciation that favored aggregation with kaolinite more than with montmorillonite. With kaolinite, the zwitterionic ligand-coated QD exhibited greater than ten times the relative attachment efficiency for QD-clay heteroaggregation compared to the negatively charged ligand coated QD. Under some conditions, particle oxidative dissolution and dynamic sorption of ions and QDs to surfaces complicated the interpretation of the removal kinetics. This work demonstrates that QDs stabilized by small molecule ligands and electrostatic surface charges are highly sensitive to changes in water chemistry in complex media. Natural environments enable rapid dynamic physicochemical changes that will influence the fate and mobility of ENMs, as seen by the differential adsorption of water-soluble QDs to our clay media.

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Section: Resultsmentioning

confidence: 99%

Ligands and media impact interactions between engineered nanomaterials and clay minerals

et al. 2019

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“…Thiolated or non‐thiolated carboxylic acids, as capping agents, have been intensively studied recently in regard of metal ion sensing based on cadmium chalcogenide nanocrystals, due to the different affinity of metal cations to the carboxyl headgroup or to the surface of the nanocrystal itself. [ 3 ] Detection of, for example, calcium (II), [ 37 ] cobalt (II), [ 38 ] copper (II), [ 39 ] mercury (II), [ 40 ] or silver (I) [ 41 ] is based on the changes of optical properties of the nanocrystals upon addition of the cations (quenching, bleaching, or enhancement). The interaction between the cation and the surface of the nanocrystal or the ligand essentially governs the mechanism of the observed optical feature.…”

Section: Introductionmentioning

confidence: 99%

A Versatile Route to Assemble Semiconductor Nanoparticles into Functional Aerogels by Means of Trivalent Cations

Zámbó

Schlosser

Rusch

et al. 2020

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can be achieved precisely, and the variety of appearance and functionality of the nanoparticles has extended the application possibilities of this material class in the fields of sensing, [2,3] energy harvesting, [4] (photo) catalysis, [5,6] photovoltaics, [7] and biomedicine. [8] Metal chalcogenides are excellent candidates for fulfilling the requirements of the above-mentioned fields of applications, due to the well-known quantum size effect emerging in their systems consisting of nanoscaled building blocks. This phenomenon endows these nanoparticle systems with unique and tunable optical properties. [9] The most widely used class of semiconductor nanoparticles is cadmiumchalcogenides, especially the CdSe/CdS and CdSe/CdTe heteroparticles in diverse size, shape, and functionality. [10] Most importantly, the high surface-to-volume ratio of nanocrystals further enhances the activity and applicability of them. Nevertheless, there are numerous fields, where liquid-based nanoparticle systems cannot be utilized, that has enhanced the development of different self-assembly procedures providing supported or non-supported superstructures. Two main objectives govern the preparation of these assemblies: i) the preservation of the individual nanocrystal properties and ii) the extension of these optical and physicochemical properties in the self-assembled nanosystems to pave the way toward new applications. In other words, novel nanoparticlebased superstructures should combine the properties of the building blocks and the emerging new features that can be 3D nanoparticle assemblies offer a unique platform to enhance and extend the functionality and optical/electrical properties of individual nanoparticles. Especially, a self-supported, voluminous, and porous macroscopic material built up from interconnected semiconductor nanoparticles provides new possibilities in the field of sensing, optoelectronics, and photovoltaics. Herein, a method is demonstrated for assembling semiconductor nanoparticle systems containing building blocks possessing different composition, size, shape, and surface ligands. The method is based on the controlled destabilization of the particles triggered by trivalent cations (Y 3+ , Yb 3+ , and Al 3+ ). The effect of the cations is investigated via X-ray photoelectron spectroscopy. The macroscopic, self-supported aerogels consist of the hyperbranched network of interconnected CdSe/ CdS dot-in-rods, or CdSe/CdS as well as CdSe/CdTe core-crown nanoplatelets is used to demonstrate the versatility of the procedure. The non-oxidative assembly method takes place at room temperature without thermal activation in several hours and preserves the shape and the fluorescence of the building blocks. The assembled nanoparticle network provides longer exciton lifetimes with retained photoluminescence quantum yields, that make these nanostructured materials a perfect platform for novel multifunctional 3D networks in sensing. Various sets of photoelectrochemical measurements on the interconnected semiconductor nanorod s...

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“…CdSe based core-shell type quantum dots (QDs) exhibit novel properties making them attractive from both experimental and theoretical point of view [5][6][7][8][9][10][11][12]. It has been shown that coating core semiconductor with larger band gap of its kind, improve properties of nanocrystals (NCs) [13,14]. However, it is believed that lattice mismatch between the core and shell affects structural and optical properties such as band gap energy and size in core and shell [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Interfacial strain and shell thickness effect on core squeeze/stretch in core/shell quantum dots

2020

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Large surface to volume ratio in zero dimension core/shell quantum dots makes lattice mismatch induced interfacial strain vital in determining structural and optical properties of nanostructures. In this study, changes in lattice mismatch induced strain from different compressive shell (CdS-ZnS) with different thicknesses (thin and thick) are evaluated and its effect on capped core diameter is theoretically calculated. Capped core squeeze amount is compared with its initial (bare) diameter obtained from transmission electron microscopy. The capped core diameter is first calculated theoretically using effective mass approximation. Then, same diameter is obtained from modified version of effective mass approximation method that considers interfacial strain amount. Comparison of the results with bare core size obtained from transmission electron microscopy revealed effect of shell thickness imposed on capped core diameter. Results show, larger lattice mismatch between core and shell induces higher strain amount on the core thereby larger squeezes the core. At the meantime, it is shown that, thicker compressive shell enforces lower stress on core as it widens its distance from core due to lattice relaxation. Hence, core is squeezes less under thicker shell.

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Acid Dissociation of 3-Mercaptopropionic Acid Coated CdSe–CdS/Cd_0.5Zn_0.5S/ZnS Core–Multishell Quantum Dot and Strong Ionic Interaction with Ca²⁺ Ion

Cited by 16 publications

References 50 publications

Ligands and media impact interactions between engineered nanomaterials and clay minerals

Ligands and media impact interactions between engineered nanomaterials and clay minerals

A Versatile Route to Assemble Semiconductor Nanoparticles into Functional Aerogels by Means of Trivalent Cations

Interfacial strain and shell thickness effect on core squeeze/stretch in core/shell quantum dots

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