Reverse photodegradation of infrared luminescence of colloidal Ag2S quantum dots

Ovchinnikov, O. V.; Grevtseva, I. G.; Kondratenko, T. S.

doi:10.1016/j.jlumin.2018.12.019

Cited by 21 publications

(29 citation statements)

References 49 publications

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“…The studied samples were colloidal solutions of Ag 2 S QDs, passivated with TGA and aqueous TGA solutions with different pH. Colloidal Ag 2 S/TGA QDs were prepared by the aqueous synthesis technique [18,19]. All reagents (Na 2 S, AgNO 3 , TGA, NaOH) purchased from Sigma-Aldrich were of high purity.…”

Section: Methods Of Investigationmentioning

confidence: 99%

“…These approaches to the synthesis make it possible to obtain ensembles of colloidal quantum dots that are fundamentally different in their physical properties. The structural and spectral properties of such samples are considered in detail in works [18,19]. Ag 2 S QDs in solution was 2 × 10 −5 mol QDs/L.…”

Section: Methods Of Investigationmentioning

confidence: 99%

“…In this case, there are two processes leading to degradation of Ag 2 S/TGA QD luminescence intensity. The first is photolysis of Ag 2 Snanocrystals, described in detail in [18].…”

Section: Ftir Spectra Tga Molecules Passivating Ag 2 S Qdsmentioning

confidence: 99%

“…Many important problems of nanophotonics are closely related to the interaction mechanism of QDs with organic matrix, which ensure the nanostructures formation with special composition and stoichiometry. In particular, the choice of passivator molecules determines the QDs luminescent properties [18,19]. For optimization of the interface passivation conditions it is necessary to know interaction mechanism of TGA molecules and QDs interfaces.…”

Section: Introductionmentioning

confidence: 99%

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Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dots Interfaces

et al. 2020

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The mechanism features of colloidal quantum dots (QDs) passivation with thioglycolic acid molecules (TGA) for cases of different luminescent properties is considered using FTIR. This problem is considered based on FTIR spectra analysis for various ionic forms of TGA. Experimental TGA molecules FTIR spectra is interpreted, basing on the data on modeling of TGA vibrational modes, realized in the framework of density functional method (DFT /B3LYP/6-31+G(d)) taking into account the vibrations anharmonicity of every functional group. This approach provides a significant improvement in the agreement between the experimental and calculated data. FTIR spectra of Ag 2 S/TGA QDs with exciton and recombination luminescence are differ from each other and B “freeB” TGA molecules. The ν ( S − H ) TGA peak (2559 cm − 1 ) disappears in FTIR spectra of Ag 2 S/TGA QD samples. This fact indicates the interactions between TGA thiol group and dangling bonds of Ag 2 S nanocrystals. Ag 2 S QDs passivation with TGA molecules leads to emergence ν a s (COO − ) (1584 cm − 1 ) and ν s (COO − ) (1387 cm − 1 ) peaks. It indicates TGA adsorption in ionic form. For Ag 2 S/TGA QDs with exciton luminescence we observed (a) significant low-frequency shift of ν s (COO − ) peak from 1388 cm − 1 to 1359 cm − 1 and high-frequency shift of ν a s (COO − ) peak from 1567 cm − 1 to 1581 cm − 1 ; (b) change in the ratio of intensities of ν a s (COO − ) and ν s (COO − ) vibrations. This feature is caused by the change in the symmetry of TGA molecules due to passivation of Ag 2 S quantum dots.For Ag 2 S/TGA QDs with recombination luminescence, the insignificant high-frequency shift of 7–10 cm − 1 for ν a s (COO − ) at 1567 cm − 1 and low-frequency shift of 3–5 cm − 1 for ν s (COO − ) at 1388 cm − 1 , probably caused by the interaction of thiol with Ag 2 S surface is observed. Using FTIR spectra, it was found that IR luminescence photodegradation is also accompanied by changes in the thioglycolic acid molecules, which capped Ag 2 S QDs. In the case of Ag 2 S QDs with exciton luminescence, the degradation process is non-reversible. It is accompanied by TGA photodegradation with the formation of α -thiol-substituted acyl radical (S-CH 2 -CO • ) TGA.

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Section: Methods Of Investigationmentioning

confidence: 99%

Section: Methods Of Investigationmentioning

confidence: 99%

“…In this case, there are two processes leading to degradation of Ag 2 S/TGA QD luminescence intensity. The first is photolysis of Ag 2 Snanocrystals, described in detail in [18].…”

Section: Ftir Spectra Tga Molecules Passivating Ag 2 S Qdsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dots Interfaces

et al. 2020

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“…In a number of studies, manifestations of photostimulated degradation of QD luminescence intensity were detected. [8][9][10][11][12][13] Random blinking of luminescence of single quantum dots was also demonstrated. [14][15][16] Such unwanted parasitic effects in the QD luminescence strongly limit the development of many advanced applications, including those associated with single-photon light sources for quantum informatics.…”

Section: Introductionmentioning

confidence: 99%

Photostimulated control of luminescence quantum yield for colloidal Ag₂S/2-MPA quantum dots

et al. 2019

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Effect of Ag$$_{2}$$S/SiO$$_{2}$$ QDs surface structure on luminescence photostability

et al. 2023

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Reverse photodegradation of infrared luminescence of colloidal Ag2S quantum dots

Cited by 21 publications

References 49 publications

Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dots Interfaces

Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dots Interfaces

Photostimulated control of luminescence quantum yield for colloidal Ag₂S/2-MPA quantum dots

Effect of Ag$$_{2}$$S/SiO$$_{2}$$ QDs surface structure on luminescence photostability

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Reverse photodegradation of infrared luminescence of colloidal Ag2S quantum dots

Cited by 21 publications

References 49 publications

Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dots Interfaces

Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dots Interfaces

Photostimulated control of luminescence quantum yield for colloidal Ag2S/2-MPA quantum dots

Effect of Ag$$_{2}$$S/SiO$$_{2}$$ QDs surface structure on luminescence photostability

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Photostimulated control of luminescence quantum yield for colloidal Ag₂S/2-MPA quantum dots