Structural and optical study of glutathione-capped Ag–In–S nanocrystals

Lopushanska, B. V.; Azhniuk, Yu. M.; Solonenko, Dmytro; Lopushansky, V. V.; Studenyak, I.P.; Zahn, Dietrich R. T.

doi:10.1080/15421406.2020.1860535

Cited by 4 publications

(14 citation statements)

References 52 publications

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“…For the fractions #1-3, β(2θ) ¼ (8.0 AE 0.5)°, and the average size is evaluated as 1 nm, which seems noticeably below the anticipated values of 2.0-2.5 nm known for Ag-In-S QDs prepared by this technique at similar conditions. [3,5,7,46] To check the size assessment, atomic force microscopy (AFM) height profiles of individual Ag-Ga-S QDs deposited from highly diluted solutions on an atomically flat mica surface were measured (Figure 2). The mean size of the QDs for fraction #1 calculated by statistical distribution of more than 100 individual height profiles is (1.8 AE 0.3) nm.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Optical Properties of Ag–Ga–S Quantum Dots

Azhniuk

Lopushanska

Selyshchev

et al. 2022

Physica Status Solidi (b)

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Ag–Ga–S quantum dots (QDs) are obtained by colloidal synthesis in aqueous solutions with glutathione ligands at mild conditions. The QDs can be assigned to metastable orthorhombic, rhombohedral, or rocksalt‐type phases, assuming a significant internal pressure within crystallites, while the conventional tetragonal AgGaS2 phase is less likely formed. Similarly to these metastable phases, the QDs reveal a relatively narrow indirect bandgap contrary to the wide and direct bandgap of tetragonal AgGaS2. Size‐selected fractions of the colloidal solutions are separated by repeated centrifuging with addition of 2‐propanol. The QD size is evaluated from atomic force microscopy, while the crystallite size determined using the Scherrer formula is underestimated. X‐ray photoemission spectroscopy reveals that the QD composition changes from nearly stoichiometric for the fraction with the largest QDs toward Ag deficient and S rich for smaller QDs. The synthesized QDs are characterized by the absorption edge blueshift with decreasing QD size. A blueshift of the photoluminescence (PL) peak with decreasing QD size is observed as well as a nonmonotonous size dependence of the PL intensity. Raman spectra of the Ag–Ga–S QDs are discussed compared to those of bulk crystals and a strong contribution of surface phonons is revealed.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Optical Properties of Ag–Ga–S Quantum Dots

Azhniuk

Lopushanska

Selyshchev

et al. 2022

Physica Status Solidi (b)

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“…The Cu-In-S QDs obtained are characterized by broadband luminescence, although it is less intense than for Ag-In-S QDs prepared earlier by a similar method [22,23]. The first fractions with larger QDs do not exhibit noticeable PL, while, for the fractions from 3 to 5, it increases in intensity and shifts toward shorter wavelengths (higher energies), as can be seen from Fig.…”

Section: Resultsmentioning

confidence: 60%

“…The maxima can be smeared by the strong Urbach tail absorption on defect states, which are highly probable in non-stoichiometric low-dimensional compounds of this family [10]. Spectra of a similar kind are also well known for Ag-In-S QDs [11,22,23]. However, the absorption spectra of Hg-In-S colloidal QDs of the same family prepared and fractioned by a similar technique exhibited size-dependent maxima [32].…”

Section: Resultsmentioning

confidence: 90%

“…Colloidal Cu-In-S QDs were synthesized in the exchange reaction between Na 2 S and a mixture of Cu(II) and In(III) complexes in the desired proportions with glutathione (GSH) in alkaline (with addition of NH 4 OH) aqueous solutions at a relatively mild temperature (96-98 ∘ C) using an approach basically similar to the one described earlier [18,22,23]. In a typical synthesis process, we mixed 2.5 ml of deionized water with 2.4 ml of 0.5 M aqueous GSH solution and 0.8 ml of 1 M aqueous InCl 3 solution (with 0.05 ml of 0.2 M HNO 3 ).…”

Section: Methodsmentioning

confidence: 99%

“…The obtained crude QD solution was afterward subjected to the size fractioning by repeated centrifuging with addition, each time, of a new portion of a poor solvent (2-propanol C 3 H 7 OH), similarly to the procedure described earlier [10,22,23]. C 3 H 7 OH was added in portions of 0.4 ml to 4.0 ml of the QD solution obtained; then it was subjected to the centrifuging for 5 min at 4000 rpm expecting the precipitate to appear.…”

Section: Methodsmentioning

confidence: 99%

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Structural and Optical Characterisation of Size-Selected Glutathione-Capped Colloidal Cu–In–S Quantum Dots

et al. 2023

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Size-selected series of copper-deficient colloidal Cu–In–S quantum dots (QDs) stabilized with glutathione are obtained by the exchange reaction in aqueous solutions under mild synthesis conditions. The optical bandgap and photoluminescence maximum position shift toward higher energies with decreasing QD size. Based on X-ray diffraction data, the QDs are assigned to a tetragonal chalcopyrite-type structure. The average size of QDs, estimated from the Scherrer formula and from the comparison with the absorption edge-based sizing curves, exhibits a fair agreement, being in the interval of 1.2–2.9 nm. The Raman spectra of Cu–In–S QDs are analyzed with the account for the QD structure, confinement-related effects, non-stoichiometry, and possible existence of secondary phases.

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Glutathione-Capped Quaternary Ag–(In,Ga)–S Quantum Dots Obtained by Colloidal Synthesis in Aqueous Solutions

Azhniuk,

Selyshchev,

Havryliuk

et al. 2024

Ukr. J. Phys.

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Ag–(In,Ga)–S quantum dots (QDs) were obtained by colloidal synthesis from aqueous solutions with different [In]/[Ga] precursor ratios in the presence of glutathione ligands under mild conditions. Size-selected fractions of the colloidal solutions were separated by the repeated centrifuging with addition of 2-propanol. The QD chemical composition determined by X-ray photoelectron spectroscopy is noticeably In-enriched with respect to the precursor ratio. The QD size estimated from the halfwidth of X-ray diffraction peaks for the non-fractioned colloidal solutions is about 2 nm. The synthesized QDs reveal a shift of the absorption edge and the photoluminescence (PL) peak maximum toward higher energies with decreasing the QD size. Experimentally measured Raman spectra of the Ag–(In,Ga)–S QDs are noticeably affected by size-related factors.

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Structural and optical study of glutathione-capped Ag–In–S nanocrystals

Cited by 4 publications

References 52 publications

Synthesis and Optical Properties of Ag–Ga–S Quantum Dots

Synthesis and Optical Properties of Ag–Ga–S Quantum Dots

Structural and Optical Characterisation of Size-Selected Glutathione-Capped Colloidal Cu–In–S Quantum Dots

Glutathione-Capped Quaternary Ag–(In,Ga)–S Quantum Dots Obtained by Colloidal Synthesis in Aqueous Solutions

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