Capping-Ligand Effect on the Stability of CdSe Quantum Dot Langmuir Monolayers

Radhakrishnan, Chander; Lo, Michael; Knobler, Charles M.; Monbouquette, Harold G.

doi:10.1021/la104244x

Cited by 14 publications

(8 citation statements)

References 46 publications

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“…Although the hydrophobic QDs are candidates forming luminescent LB films, a few of them are developed for sensing applications. 206,207 Moreover, the LB system is not strongly stable when exposed to the ambient environment as a result of relatively weak physical adhesion in the assembly process. 208 Over the past several decades, the LB technique was gradually replaced by other simpler and more robust methods, such as SAM and LBL deposition.…”

Section: Luminescent Lb Film Biosensorsmentioning

confidence: 99%

Luminescent films for chemo- and biosensing

et al. 2015

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Luminescent films have received great interest for chemo-/bio-sensing applications due to their distinct advantages over solution-based probes, such as good stability and portability, tunable shape and size, non-invasion, real-time detection, extensive suitability in gas/vapor sensing, and recycling. On the other hand, they can achieve selective and sensitive detection of chemical/biological species using special luminophores with a recognition moiety or the assembly of common luminophores and functional materials. Nowadays, the extensively used assembly techniques include drop-casting/spin-coating, Langmuir-Blodgett (LB), self-assembled monolayers (SAMs), layer-by-layer (LBL), and electrospinning. Therefore, this review summarizes the recent advances in luminescent films with these assembly techniques and their applications in chemo-/bio-sensing. We mainly focused on the discussion of the relationship between the sensing properties of the films and their architecture. Furthermore, we discussed some critical challenges existing in this field and possible solutions that have been or are being developed to overcome these challenges.

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Section: Luminescent Lb Film Biosensorsmentioning

confidence: 99%

Luminescent films for chemo- and biosensing

et al. 2015

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“…Therefore, nanoparticle stabilization against detrimental aggregation is a critical parameter that needs to be well controlled, 3 and aggregationresistant, water-soluble nanoparticles without nonspecific adsorption are desirable, especially in the application of cell imaging and single nanoparticle tracking. 4 In general, the aggregation usually arose from noncovalent interaction, for example, hydrogen-bonding interaction, 5,6 van der Waals forces, 7 and electrostatic forces 8,9 between the nanoparticles. Thus, the shielding of noncovalent interactions between nanoparticles is one of the approaches to minimize nanoparticle aggregation.…”

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confidence: 99%

Aggregation Control of Quantum Dots through Ion-Mediated Hydrogen Bonding Shielding

Yang

Wang

et al. 2012

ACS Nano

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Nanoparticle stabilization against detrimental aggregation is a critical parameter that needs to be well controlled. Herein, we present a facile and rapid ion-mediated dispersing technique that leads to hydrophilic aggregate-free quantum dots (QDs). Because of the shielding of the hydrogen bonds between cysteamine-capped QDs, the presence of F(-) ions disassembled the aggregates of QDs and afforded their high colloidal stability. The F(-) ions also greatly eliminated the nonspecific adsorption of the QDs on glass slides and cells. Unlike the conventional colloidal stabilized method that requires the use of any organic ligand and/or polymer for the passivation of the nanoparticle surface, the proposed approach adopts the small size and large diffusion coefficient of inorganic ions as dispersant, which offers the disaggregation a fast reaction dynamics and negligible influence on their intrinsic surface functional properties. Therefore, the ion-mediated dispersing strategy showed great potential in chemosensing and biomedical applications.

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“…The physicochemical properties of Langmuir monolayers based on nanosized objects and the peculiarities of their formation are determined by the stabilizer used during their synthesis. In particular, the choice of the stabilizer affects both the shape of the compression isotherms and the stability of monolayers onto the subphase surface. , It is known that the difference between the specific areas of QDs at the beginning and end of the liquid-expanded phase of the isotherm increases with an increase in their size . At the same time, there are a number of common features for different types of stabilizers.…”

Section: Resultsmentioning

confidence: 99%

“…The position of the QD relative to the water surface depends on the type of stabilizer molecules and the QD’s size. This is a phenomenon connected with alterations in desorption kinetics of QDs covered by different types of stabilizer molecules . In the case of a QD with diameter d = 8 nm and TOPO as a stabilizer for further calculations, we will assume that the QD is half immersed in water, that is, ∼24 AA molecules can fit in the gap between QDs.…”

Section: Resultsmentioning

confidence: 99%

“…This is a phenomenon connected with alterations in desorption kinetics of QDs covered by different types of stabilizer molecules. 31 In the case of a QD with diameter d = 8 nm and TOPO as a stabilizer for further calculations, we will assume that the QD is half immersed in water, that is, ∼24 AA molecules can fit in the gap between QDs. Also, during the formation of a QD/AA mixture, partial replacement of TOPO molecules with AA into the QD shell is possible.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Morphology of Mixed Langmuir and Langmuir–Schaefer Monolayers with Covered CdSe/CdS/ZnS Quantum Dots and Arachidic Acid

et al. 2021

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The process of formation of a Langmuir−Schaefer (LS) matrix based on a mixed monolayer of arachidic acid (AA) and 8 nm CdSe/CdS/ZnS quantum dots (QDs) stabilized by molecules of trioctylphosphine oxide (TOPO) was investigated. The change in the morphology, monolayer compressibility, and area per elementary cell of the created mixed monolayers, depending on the ratio of the components, was studied. It is shown that the change in the morphology of Langmuir−Blodgett (LB) monolayers begins to occur at a ratio between the number of QDs and AA molecules of 1:24. Dendrimeric structures with a thickness of the order of 30−40 nm appear in the mixed monolayer when LB film deposition was carried out above the collapse surface pressure of a Langmuir film from only TOPOcovered QDs. Information on the dependence of the morphology of such structures on the molar ratio of the components is necessary for the production of ordered 2D nanostructures containing 0D and 1D objects with quantum bonds. Such nanostructures can be used in nanoelectronic and optoelectronic devices as a sensitive sensor element. The obtained results would be relevant for any type of spherical shape nanoparticles.

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Capping-Ligand Effect on the Stability of CdSe Quantum Dot Langmuir Monolayers

Cited by 14 publications

References 46 publications

Luminescent films for chemo- and biosensing

Luminescent films for chemo- and biosensing

Aggregation Control of Quantum Dots through Ion-Mediated Hydrogen Bonding Shielding

Morphology of Mixed Langmuir and Langmuir–Schaefer Monolayers with Covered CdSe/CdS/ZnS Quantum Dots and Arachidic Acid

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