Clustering of CdSe/CdS Quantum Dot/Quantum Rods into Micelles Can Form Bright, Non-blinking, Stable, and Biocompatible Probes

Rafipoor, Mona; Schmidtke, Christian; Wolter, Christopher; Strelow, Christian; Weller, Horst; Lange, Holger

doi:10.1021/acs.langmuir.5b01570

Cited by 19 publications

(27 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…QDQRs are applied as fluorescent reporters e.g., in bioanalysis and microscopy, 1,2 and optoelectronic components in photovoltaics, light-emitting diodes (LEDs), and liquid crystal displays (LCDs). [3][4][5][6] Such QDQRs can have different aspect ratios, i.e., different ratios of their length and thickness, and are commonly covered by a coordinatively bound shell of organic ligands controlling their stability and dispersibility.…”

Section: Introductionmentioning

confidence: 99%

Excitation wavelength dependence of the photoluminescence quantum yield and decay behavior of CdSe/CdS quantum dot/quantum rods with different aspect ratios

Geißler

Würth

Wolter

et al. 2017

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

The excitation wavelength (λ) dependence of the photoluminescence (PL) quantum yield (Φ) and decay behavior (τ) of a series of CdSe/CdS quantum dot/quantum rods (QDQRs), consisting of the same spherical CdSe core and rod-shaped CdS shells, with aspect ratios ranging from 2 to 20 was characterized. λ between 400-565 nm were chosen to cover the first excitonic absorption band of the CdSe core material, the onset of absorption of the CdS shell, and the region of predominant shell absorption. A strong λ dependence of relative and absolutely measured Φ and τ was found particularly for the longer QDQRs with higher aspect ratios. This is attributed to combined contributions from a length-dependent shell-to-core exciton localization efficiency, an increasing number of defect states within the shell for the longest QDQRs, and probably also the presence of absorbing, yet non-emitting shell material. Although the Φ values of the QDQRs decrease at shorter wavelength, the extremely high extinction coefficients introduced by the shell outweigh this effect, leading to significantly higher brightness values at wavelengths below the absorption onset of the CdS shell compared with direct excitation of the CdSe cores. Moreover, our results present also an interesting example for the comparability of absolutely measured Φ using an integrating sphere setup and Φ values measured relative to common Φ standards, and underline the need for a correction for particle scattering for QDQRs with high aspect ratios.

show abstract

Section: Introductionmentioning

confidence: 99%

Excitation wavelength dependence of the photoluminescence quantum yield and decay behavior of CdSe/CdS quantum dot/quantum rods with different aspect ratios

Geißler

Würth

Wolter

et al. 2017

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…For the detailed investigations, we employed individual NCs in micelles (single), one reference sample of large micelles with long average interparticle distance (cluster 1) and three sets of micelles with the same sizes and decreasing interparticle distances (clusters 2–4). Our earlier studies suggest that the polymer functionlization of the core‐shell NCs has negligible impact on the optical properties of the individual NCs . Reference experiments experiments on the NCs prior to encapsulation confirm this (see the Supporting Information).…”

Section: Resultsmentioning

confidence: 53%

“…QDs/QRs were synthesized according to the protocol used earlier . The syntheses of the polymers are described elsewhere …”

Section: Methodsmentioning

confidence: 99%

“…Liz‐Marzán and co‐workers demonstrated the possibility for a distance control by employing stabilizing polymers of different masses . Motivated by interaction signatures observed in core/shell quantum dots/quantum rods (QDs/QRs) stabilized in micelles, we expanded our encapsulation technique accordingly. The interparticle distance within the micelles can be controlled by functionalizing the NCs with polymer ligands of defined mass.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Resonant Energy Transfer can Trigger Multiexciton Recombination in Dense Quantum Dot Ensembles

Rafipoor

Koll

Merkl

et al. 2018

Small

Self Cite

View full text Add to dashboard Cite

Core/shell quantum dots/quantum rods are nanocrystals with typical application scenarios as ensembles. Resonance energy transfer is a possible process between adjacent nanocrystals. Highly excited nanocrystals can also relax energy by multiexciton recombination, competing against the energy transfer. The two processes have different dependencies and can be convolved, resulting in collective properties different from the superposition of the individual nanocrystals. A platform to study the interplay of energy transfer and multiexciton recombination is presented. CdSe/CdS quantum dot/quantum rods encapsulated in amphiphilic micelles with an interparticle distance control by spacer ligands are used for time‐resolved photoluminescence and transient absorption experiments. At exciton populations around one, the ensemble starts to be in a state where energy transfer can trigger multiexciton Auger recombination, altering the collective dynamics.

show abstract

“…Among fluorescent probes, quantum dots as a new fluorescent probe have been widely applied in the field of medical imaging due to their high quantum yields, photostability, broad excitation spectra, and narrow, tunable emission spectra. However, quantum dots are commonly made of heavy metals (eg, CdS, CdSe, ZnSe, and PbS) . Although they have superior optical properties, their application in biomedical field is limited due to their intrinsic cytotoxicity.…”

Section: Introductionmentioning

confidence: 99%

A pH‐responsive self‐fluorescent polymeric micelle as a potential optical imaging probe

Jiang

2018

Polymers for Advanced Techs

View full text Add to dashboard Cite

A series of methoxypolyethylene glycol‐terminated self‐fluorescent polyurethane multi‐block copolymers with excellent pH‐responsivity, self‐fluorescence, and biocompatibility are designed and synthesized. In our design, 1, 4‐bis (hydroxyethyl) piperazine is chosen as a pH‐responsive segment which can donate or accept protons in response to the change of environmental pH, and fluorescein isothiocyanate is used as a fluorescent dye conjugated into the micelles to offer self‐fluorescence. The chemical structure of the polyurethane multi‐block copolymers is characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. The results of the acid‐based titration, the fluorescence spectrometry, and the ultraviolet visible spectroscopy indicate that the polyurethane multi‐block copolymers own an excellent pH‐buffering capacity responded to the change of pH values and the favorable self‐fluorescence property in an aqueous solution. And the ultraviolet absorption peaks of samples are strengthened with increasing of pH values, indicating that methoxypolyethylene glycol‐terminated self‐fluorescent polyurethane multi‐block copolymer can be a pH‐dependent fluorescent probe in a broad pH range. In addition, the in vitro cytotoxicity test showed that the polyurethane multi‐block copolymer has low cytotoxicity and good biocompatibility, which make it a promising nanoplatform for molecular imaging, diagnosis, and treatment of disease.

show abstract

Clustering of CdSe/CdS Quantum Dot/Quantum Rods into Micelles Can Form Bright, Non-blinking, Stable, and Biocompatible Probes

Cited by 19 publications

References 29 publications

Excitation wavelength dependence of the photoluminescence quantum yield and decay behavior of CdSe/CdS quantum dot/quantum rods with different aspect ratios

Excitation wavelength dependence of the photoluminescence quantum yield and decay behavior of CdSe/CdS quantum dot/quantum rods with different aspect ratios

Resonant Energy Transfer can Trigger Multiexciton Recombination in Dense Quantum Dot Ensembles

A pH‐responsive self‐fluorescent polymeric micelle as a potential optical imaging probe

Contact Info

Product

Resources

About