Photoactivation, photobleaching and photoetching of CdS quantum dots − Role of oxygen and solvent

Chashchikhin, Oleg V.; Будыка, М. Ф.

doi:10.1016/j.jphotochem.2017.04.028

Cited by 14 publications

(4 citation statements)

References 40 publications

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“…These imperfections on the surface act as trap states for charge carriers that cause nonradiative recombination of excitons and reduce PL properties. However, when QDs are in contact with oxygen and water, these trap states can be passivated through oxidation reactions, allowing the electrons to repopulate in the conduction band and hence enhance PL properties. ,− This phenomenon is called photoactivation. For nanocomposite films under high temperature and humidity, oxygen and water molecules can permeate through the polymer layer and reach the surface of the QDs, leading to photoactivation and an enhanced PL property.…”

Section: Results and Discussionmentioning

confidence: 99%

Assessing Stability of Nanocomposites Containing Quantum Dot/Silica Hybrid Particles with Different Morphologies at High Temperature and Humidity

Heo

Lee

2020

Chem. Mater.

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In this study, we investigate the photoluminescence stability of nanocomposites containing quantum dot (QD)/silica hybrid particles against high temperature and humidity. First, hybrid particles with different morphologies, such as silica/QD/silica (SQS), QD/mesoporous silica (MSQ), and QD/wrinkled silica (WSQ), were synthesized and dispersed in a commercially available silicone resin (Sylgard-184). We performed stability tests on these nanocomposites at 100 °C/85% RH for 72 h and found that their quantum efficiencies were maintained or even increased during the test, whereas a nanocomposite containing bare QDs exhibited a significant decrease in quantum efficiency. The enhancement in quantum efficiencies of the nanocomposites containing the MSQ and SQS particles was attributed to the photoactivation phenomenon. To further investigate the stability after exposure to heat and moisture, we measured quantum efficiencies of the photoactivated nanocomposites after storing them for 10 days under ambient conditions. Those efficiencies significantly decreased to values even lower than the initial values. However, quantum efficiency of the nanocomposite containing WSQ particles remained constant during and after the stability test because of the particle morphology. Therefore, we conclude that the nanocomposite containing the WSQ particles was most stable against high temperature and humidity and that the photoactivation was not desirable for the stability of nanocomposites, although it initially enhanced the photoluminescence properties.

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Section: Results and Discussionmentioning

confidence: 99%

Assessing Stability of Nanocomposites Containing Quantum Dot/Silica Hybrid Particles with Different Morphologies at High Temperature and Humidity

Heo

Lee

2020

Chem. Mater.

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“…This stability extends to how the reagents are handled compared to other fluorescent materials: quantum dots, for example, are subject to photooxidation which influences surface functionality and emission properties [ 29 ]. This characteristic limits their use to environments that are oxygen- and moisture-free [ 30 ]. FNDs are able to withstand sterilization through autoclaving, heating, high energy irradiation, and freezing during storage [ 31 , 32 , 33 ].…”

Section: Discussionmentioning

confidence: 99%

Clot Imaging Using Photostable Nanodiamond

et al. 2023

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While thrombosis is the leading cause of morbidity and mortality in the United States, an understanding of its triggers, progression, and response to anticoagulant therapy is lacking. Intravital fluorescence microscopy has advanced the study of thrombus formation by providing targeted, multi-color contrast. However, photodegradation of fluorophores limits the application in longitudinal studies (e.g., clot progression and/or dissolution). Fluorescent nanodiamond (FND) is a fluorophore which utilizes intrinsic fluorescence of chromogenic centers within and protected by the diamond crystalline lattice. Recent developments in diamond processing have allowed for the controlled production of nanodiamonds emitting in green or red. Here, the use of FND to label blood clots and/or clot lysis is demonstrated and compared to commonly used organic fluorophores. Model ex vivo clots were formed with incorporated labeled fibrinogen to allow imaging. FND was shown to match the morphology of organic fluorophore labels absent of photobleaching over time. The addition of tissue plasminogen activator (tPa) allowed visualization of the clot lysis stage, which is vital to studies of both DVT and pulmonary embolism resolution.

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“…QDs were synthesized as previously reported. [37,51] QDs extinction coefficient was calculated from standard empiric equations. [38] 2-((E)-2-anthracen-9-yl-vinyl)-quinoline-6-carboxylic acid (AQE-FL) was synthesized as previously reported (details provided in SI).…”

Section: Methodsmentioning

confidence: 99%

Photomodulation of a Dual‐Color Luminescent System Combining Quantum Dots with a FRET Acceptor Ligand**

Будыка

Nikulin²,

Гавришова

et al. 2021

ChemPhotoChem

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Herein, we report on a dual-color, photoswitchable donoracceptor nanosystem based on quantum dots (QD) and an anthryl quinolyl ethylene photoactive functional ligand (AQE-FL), in which a carboxylic group is used to anchor AQE-FL to QD. Photophysical and photochemical properties of the resulting photoswitchable QD system (psQD) were studied by steady state and time-resolved spectroscopic methods. Efficient Förster resonance energy transfer (FRET) from QD to AQE-FL was shown. Applicability of the Stern-Volmer formalism (with a subdivision into static and dynamic quenching) to the psQD studied is discussed. The spectral overlap integrals of QD emission and trans-and cis-AQE-FL isomers absorption differ by 3 times that which is used for controlling the FRET efficiency. Consequently, the psQD emission is redistributed between the QD (417 nm) and AQE (520 nm) channels, i. e. dual-color fluorescent switching between two observable states without the "off" state is recorded.

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Photoactivation, photobleaching and photoetching of CdS quantum dots − Role of oxygen and solvent

Cited by 14 publications

References 40 publications

Assessing Stability of Nanocomposites Containing Quantum Dot/Silica Hybrid Particles with Different Morphologies at High Temperature and Humidity

Assessing Stability of Nanocomposites Containing Quantum Dot/Silica Hybrid Particles with Different Morphologies at High Temperature and Humidity

Clot Imaging Using Photostable Nanodiamond

Photomodulation of a Dual‐Color Luminescent System Combining Quantum Dots with a FRET Acceptor Ligand**

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