Luminescence and nonlinear optical properties of colloidal Ag2S quantum dots

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

doi:10.1016/j.jlumin.2018.12.042

Cited by 38 publications

(13 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…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%

“…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%

See 2 more Smart Citations

Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dots Interfaces

et al. 2020

View full text Add to dashboard Cite

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.

show abstract

Section: Methods Of Investigationmentioning

confidence: 99%

Section: Methods Of Investigationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thioglycolic Acid FTIR Spectra on Ag2S Quantum Dots Interfaces

et al. 2020

View full text Add to dashboard Cite

show abstract

“…10,11,23,26,31 In the case of using molecules of thioglycolic acid (TGA) as the passivating agent, a strong dependence of the QD optical properties on the sulfur concentration and the silver-sulfur ratio is observed. 10,11,[31][32][33] In the works, 10,11,31 it was assumed that the centers of radiative recombination of Ag 2 S QDs are of an interfacial nature. The low quantum yield of the QDs is explained, as a rule, by numerous surface defects formed during rapid intense release of sulfur atoms involved in the QD growth.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Kumar et al prepared visible-light-active nano-sized Ag 2 S-ZnS loaded on cellulose by a precipitation method and studied photocatalytic degradation of rhodamine B dye [15]. From the viewpoint of nonlinear optics, Ag 2 S can be considered as an appropriate candidate to enhance optical nonlinearities in ZnS nanostructures due to nonlinear features such as two-photon absorption and nonlinear refractive index, which have been demonstrated at 532 nm [16].…”

Section: Introductionmentioning

confidence: 99%

Facile synthesis of ZnS–Ag2S core–shell nanospheres with enhanced nonlinear refraction

Haghighatzadeh

Kiani

Mazinani

et al. 2019

J Mater Sci: Mater Electron

View full text Add to dashboard Cite

ZnS-Ag 2 S core-shell nano/hetero-junctions have been synthesized by a two-step co-precipitation technique, in which thin layers of Ag 2 S have been successfully coated on the surface of ZnS nanospheres. Structural studies and elemental analysis have been performed using X-ray diffraction, Fourier transfer infrared spectroscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, and high-resolution transmission electron microscopy. UV-Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy have been employed to investigate linear optical characteristics. Nanosecond laser pulsed-based single-beam Z-scan analysis has been used to examine the magnitude and the sign of the third-order nonlinear refractive indices. Samples show negative values of nonlinear refractive indices indicating self-defocusing optical nonlinearity under 1064 nm excitation. The results have shown that the third-order nonlinear refractive index in ZnS nanospheres can reach the magnitude of 61.0 × 10 −12 m 2 ∕W by encapsulating such a nanostructure within nanometer shells of Ag 2 S. The enhanced nonlinearity for ZnS-Ag 2 S core-shells has been found to be 9 times higher than sole ZnS nanoparticles, which was estimated to be about 6.4 × 10 −12 m 2 ∕W.

show abstract

Luminescence and nonlinear optical properties of colloidal Ag2S quantum dots

Cited by 38 publications

References 44 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

Facile synthesis of ZnS–Ag2S core–shell nanospheres with enhanced nonlinear refraction

Contact Info

Product

Resources

About

Luminescence and nonlinear optical properties of colloidal Ag2S quantum dots

Cited by 38 publications

References 44 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

Facile synthesis of ZnS–Ag2S core–shell nanospheres with enhanced nonlinear refraction

Contact Info

Product

Resources

About

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