Optimum quantum dot size for highly efficient fluorescence bioimaging

Maestro, Laura Martínez; Jacinto, Carlos; Rocha, Uéslen; Cruz, M. Carmen Iglesias-de la; Sanz-Rodrı́guez, Francisco; Juarranz, Ángeles; Solé, J. Garcı́a; Jaque, Daniel

doi:10.1063/1.3676251

Cited by 30 publications

(12 citation statements)

References 36 publications

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“…The decrease of QD size implies an increase of the surface‐to‐volume ratio and accordingly nonradiative decay rate (

τ_{nr}^{- 1}

) through the trap‐related states. At the same time, a monotonic increase of the radiative decay rate (

τ_{r}^{- 1}

) is predicted as the emission frequency increases (i.e., as the QD size decreases), in accord with experimental observations and as predicted by Fermi's Golden Rule. The resulting PL lifetime, determined as

τ = {(τ_{r}^{- 1} + τ_{nr}^{- 1})}^{- 1},

for small QDs shows fast radiative and nonradiative decay rates, leading to fast nonexponential decay curves.…”

Section: Resultssupporting

confidence: 84%

Temperature-Dependent Exciton and Trap-Related Photoluminescence of CdTe Quantum Dots Embedded in a NaCl Matrix: Implication in Thermometry

Kalytchuk

Zhovtiuk

Kershaw

et al. 2015

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117

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Temperature-dependent optical studies of semiconductor quantum dots (QDs) are fundamentally important for a variety of sensing and imaging applications. The steady-state and time-resolved photoluminescence properties of CdTe QDs in the size range from 2.3 to 3.1 nm embedded into a protective matrix of NaCl are studied as a function of temperature from 80 to 360 K. The temperature coefficient is found to be strongly dependent on QD size, with the highest sensitivity obtained for the smallest size of QDs. The emission from solid-state CdTe QD-based powders is maintained with high color purity over a wide range of temperatures. Photoluminescence lifetime data suggest that temperature dependence of the intrinsic radiative lifetime in CdTe QDs is rather weak, and it is mostly the temperature-dependent nonradiative decay of CdTe QDs which is responsible for the thermal quenching of photoluminescence intensity. By virtue of the temperature-dependent photoluminescence behavior, high color purity, photostability, and high photoluminescence quantum yield (26%-37% in the solid state), CdTe QDs embedded in NaCl matrices are useful solid-state probes for thermal imaging and sensing over a wide range of temperatures within a number of detection schemes and outstanding sensitivity, such as luminescence thermochromic imaging, ratiometric luminescence, and luminescence lifetime thermal sensing.

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“…The decrease of QD size implies an increase of the surface‐to‐volume ratio and accordingly nonradiative decay rate (

τ_{nr}^{- 1}

) through the trap‐related states. At the same time, a monotonic increase of the radiative decay rate (

τ_{r}^{- 1}

τ = {(τ_{r}^{- 1} + τ_{nr}^{- 1})}^{- 1},

for small QDs shows fast radiative and nonradiative decay rates, leading to fast nonexponential decay curves.…”

Section: Resultssupporting

confidence: 84%

Temperature-Dependent Exciton and Trap-Related Photoluminescence of CdTe Quantum Dots Embedded in a NaCl Matrix: Implication in Thermometry

Kalytchuk

Zhovtiuk

Kershaw

et al. 2015

Small

117

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“…Figure d shows the normalized emission spectra of CdTe and CdTe–PNA under CW excitation at 365 nm. For CdTe QDs, the very symmetric emission spectrum indicates that the QDs were well-cooked, while the emission peak position at 569 nm in CdTe QDs agrees well with the size of about 3 nm and our TEM morphology results of CdTe as well. After linking to PNA, the emission peak of CdTe shows a 6 nm blue shift from 569 to 563 nm (Figure d) for the sample with molar ratio 2200:1 of radicals to CdTe.…”

Section: Resultssupporting

confidence: 84%

Photoluminescent CdTe Quantum Dot-Polynitroxylated Albumin Composites for Glutathione Detection

Zhang

Zou

et al. 2022

ACS Appl. Nano Mater.

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We have linked a new type of stable nitroxyl radical, polynitroxylated albumin (PNA), to cadmium telluride (CdTe) quantum dots (QDs) to form CdTe–PNA nanocomposites, in which PNA can effectively quench QDs’ photoluminescence (PL). We have demonstrated that CdTe–PNA can be used for glutathione detection by measuring the PL recovery. Utilizing the albumin as a linker between QDs and the radicals, the water-soluble CdTe–PNA probe exhibits good biocompatibility and luminescent properties. Using static PL, lifetime, and electron paramagnetic resonance spectroscopy measurements, we have proposed a CdTe PL quenching mechanism based on quencher PNA. The results indicate that QDs reduce nitroxides on PNA to hydroxylamines, and dynamic quenching is the predominant process. The optimized formula has a 2200:1 molar ratio of nitroxide to QDs, which gives a lower limit of glutathione detection of 20 nM and a linearity range of 5–60 μM (R 2 = 0.99). In addition, cytotoxicity testing shows that introducing albumin can effectively reduce the cytotoxicity from both CdTe QDs and nitroxide radicals. Because PNA has 30 nitroxides per albumin, the detection advantages of CdTe–PNA can be attributed to the high local concentration of nitroxides and a redox cycling process of electron transfer between QDs and polynitroxides. The new CdTe–PNA PL nanocomposite has broadened application perspectives of QDs in the diagnosis of cancers or other diseases when using glutathione as a biomarker.

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“…Moreover, only recently, a unity PL QY was reported for CdSe/CdS nanorods excited at 3.057 eV (405 nm), where most of the absorption occurred directly into the shell, thereby demonstrating complete shell-to-core energy transfer . Other research groups, however, noticed an EED of PL QY for CdSe, CdSe/CdS, CdSe/ZnS, CdSe/ZnS/CdSe, CdTe, and InP QDs, particularly a decrease in PL QY for excitation energies above the effective band gap. ,− Explanations for this observation range from an overestimation of the absorption of the samples at higher energies to surface mediated nonradiative deactivation of the excitons formed upon light absorption. Possible nonradiative decay pathways are the coupling of the charge carriers to the organic ligands on the QD surface as suggested by the Loomis group ,− or the opening of a continuum of higher energy, nonradiative states, which reduces the efficiency for relaxation of the charge carriers to the band edge as proposed by the Alivisatos group .…”

Section: Introductionmentioning

confidence: 99%

Excitation Energy Dependence of the Photoluminescence Quantum Yield of Core/Shell CdSe/CdS Quantum Dots and Correlation with Circular Dichroism

et al. 2018

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Quantum dot (QD) based nanomaterials are very promising materials for the fabrication of optoelectronic devices like solar cells, light emitting diodes (LEDs), and photodetectors as well as as reporters for chemo-and biosensing and bioimaging. Many of these applications involve the monitoring of changes in photoluminescence intensity and energy transfer processes which can strongly depend on excitation wavelength or energy. In this work, we analyzed the excitation energy dependence (EED) of the photoluminescence quantum yields (PL QYs) and decay kinetics and the circular dichroism (CD) spectra of CdSe/CdS core/shell QDs with different thicknesses of the surface passivation shell. Our results demonstrate a strong correlation between the spectral position of local maxima observed in the EED of PL QY and the zero-crossing points of the CD profiles. Theoretical analysis of the energy band structure of the QDs with effective mass approximation suggests that these structures could correspond to exciton energy levels. This underlines the potential of CD spectroscopy for the study of electronic energy structure of chiroptically active nanocrystals which reveal quantum confinement effects.

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Optimum quantum dot size for highly efficient fluorescence bioimaging

Cited by 30 publications

References 36 publications

Temperature-Dependent Exciton and Trap-Related Photoluminescence of CdTe Quantum Dots Embedded in a NaCl Matrix: Implication in Thermometry

Temperature-Dependent Exciton and Trap-Related Photoluminescence of CdTe Quantum Dots Embedded in a NaCl Matrix: Implication in Thermometry

Photoluminescent CdTe Quantum Dot-Polynitroxylated Albumin Composites for Glutathione Detection

Excitation Energy Dependence of the Photoluminescence Quantum Yield of Core/Shell CdSe/CdS Quantum Dots and Correlation with Circular Dichroism

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