Unique Luminescent Properties of Composition-/Size-Selected Aqueous Ag-In-S and Core/Shell Ag-In-S/ZnS Quantum Dots

Stroyuk, Oleksandr; Raievska, Oleksandra; Zahn, Dietrich R. T.

doi:10.1007/978-3-030-46596-4_3

Cited by 6 publications

(24 citation statements)

References 158 publications

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“…These reversible PL changes that could be repeated cyclically were attributed to thermally activated reversible dissociation of surface GSH complexes and introduction of water molecules into the surface layer of AIS QDs that acted as a "pool" for vibrational dissipation of excitation energy. 11,13 In the present systems we observe an opposite trend, as the shortening of τ PL occurs due to the water elimination and, therefore, we cannot explain the PL quenching upon film formation by decreased interactions between the QD surface and solvent molecules. In the same manner, we cannot assign these PL changes exclusively to interactions between QDs and PVP molecules because the PL changes have the same character both for PVP films and solid QD films without polymer additives.…”

Section: ■ Results and Discussioncontrasting

confidence: 73%

“…General Description of the Samples and Approaches. In our previous reports 11,12,14,16,17 we showed that the stepwise precipitation−redispersion using an antisolvent is a perfect tool to produce relatively broad series of size-selected core AIS and core/shell AIS/ZnS QDs from aqueous colloidal ensembles of QDs capped by multifunctional ligands (thioglycolic acid or glutathione). The redispersion of precipitated QD fractions allows concentrated and very stable QD colloids to be produced that emit bright multicolor PL and maintain optical properties unchanged for years of dark-shelf storage.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The decrease of the PL QY for smaller QDs (the larger-bandgap wing of the dependence) can be assigned either to a higher disorder in the smaller QDs or to a stronger interaction with the solvent/ dissolved species favoring vibrational dissipation of the excitation energy and interfacial electron transfer. 11,13 The core/shell QDs form a generally similar dome-shaped relationship but with a lower degree of correspondence between the different compositions, most probably due to a different character of Zn II diffusion into cores of different composition. The maximal PL QYs observed for ZAIS-4 QDs reach 54−55% and fall to less than 10% for higher bandgaps in the set of ZAIS-8 samples.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Recently we reported on reversible quenching/dequenching effects for colloidal AIS and ZAIS QDs. 11,13 Heating of colloidal solutions up to 80 °C was found to result in PL quenching and a shortening of τ PL while and cooling back to 10 °C resulted in the restoration of PL intensity and lifetime. These reversible PL changes that could be repeated cyclically were attributed to thermally activated reversible dissociation of surface GSH complexes and introduction of water molecules into the surface layer of AIS QDs that acted as a "pool" for vibrational dissipation of excitation energy.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Here we report on high-throughput characterization of photophysical properties of nonstoichiometric aqueous colloidal Ag–In–S QDs of different sizes and compositions by time-resolved (TR) photoluminescence (PL) spectroscopy. This study was stimulated by our recent probes into the TRPL behavior of composition-selected AIS QDs − as well as of size-selected series of AIS QDs of the same composition. − To perform such a study, we apply a custom-designed robotic setup allowing the PL decays curves to be registered at specified spectral points automatically for a broad array of samples. Combining this technique with our expertise in the aqueous synthesis of AIS-based QDs with the QD composition and size tuned separately in the frame of a general synthetic approach, we carry out the photophysical characterization in the high-throughput regime with hundreds of QDs samples produced and probed in the same conditions both in the form of colloidal solutions and thin films.…”

Section: Introductionmentioning

confidence: 99%

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High-Throughput Time-Resolved Photoluminescence Study of Composition- and Size-Selected Aqueous Ag–In–S Quantum Dots

et al. 2021

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Brightly luminescent, composition- and size-selected aqueous Ag–In–S (AIS) and Zn-diffused core/shell AIS/ZnS (ZAIS) quantum dots (QDs) were studied by high-throughput time-resolved photoluminescence (TRPL). Both QD size and QD composition effects on the photophysical properties of AIS (ZAIS) were probed independently by using an automated high-throughput TRPL setup. Linear relationships were found between the average PL lifetimes of AIS and ZAIS QDs and their respective bandgaps (E g) indicating that the dynamics of the radiative recombination is governed mostly by the energy of the QD excited state irrespective of which factor is varied affecting the QD bandgap, i.e., their size or composition. The rate constants of radiative and nonradiative recombination were evaluated as a function of E g forming continuous dependences for the entire AIS and ZAIS QD families. The rate of nonradiative recombination increases steeply for smaller QDs with E g > 2.2 eV for both core AIS and core/shell ZAIS QDs, indicating that the interfacial electron transfer is the major contributor to the observed dependence. A strong decrease of the PL lifetime of AIS (and ZAIS) QDs in dense QD films or QDs incorporated into polyvinylpyrrolidone films was observed as compared to colloidal solutions. A reversible character of this effect upon polymer film dissolution shows that such behavior originates from energy (or electron) transfers among the QDs brought into close contact in the films. This phenomenon is expected to be of significance for the application of ternary QDs as a light-harvesting material.

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Section: ■ Results and Discussioncontrasting

confidence: 73%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-Throughput Time-Resolved Photoluminescence Study of Composition- and Size-Selected Aqueous Ag–In–S Quantum Dots

et al. 2021

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Exploring Highly Efficient Broadband Self‐Trapped‐Exciton Luminophors: from 0D to 3D Materials

Stroyuk,

Raievska,

Zahn

et al. 2023

The Chemical Record

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The review summarizes our recent reports on brightly‐emitting materials with varied dimensionality (3D, 2D, 0D) synthesized using “green” chemistry and exhibiting highly efficient photoluminescence (PL) originating from self‐trapped exciton (STE) states. The discussion starts with 0D emitters, in particular, ternary indium‐based colloidal quantum dots, continues with 2D materials, focusing on single‐layer polyheptazine carbon nitride, and further evolves to 3D luminophores, the latter exemplified by lead‐free double halide perovskites. The review shows the broadband STE PL to be an inherent feature of many materials produced in mild conditions by “green” chemistry, outlining PL features general for these STE emitters and differences in their photophysical properties. The review is concluded with an outlook on the challenges in the field of STE PL emission and the most promising venues for future research.

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Singlet oxygen generation by nanoassemblies containing porphyrin macrocycles: Steric and screening effects, energy transfer and competing processes

Zenkevich,

Parkhats,

Dzhagarov

et al. 2024

J. Porphyrins Phthalocyanines

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In this semi-review paper, we discuss some principal aspects that should be taken into account upon quantitative analysis of the interaction with molecular oxygen O2 and the singlet oxygen (1O2 or [Formula: see text] generation by various tetrapyrrolic photosensitizers (including monomers, chemical dimers, triads, pentads and organic-inorganic nanoassemblies). In all cases, the direct experimental measurements of 1O2 emission at [Formula: see text] = 1.27 μ need to be corrected to the solvent influence (refractive indexes, molecular polarizability) on the rate constant of the radiative transition [Formula: see text] in a 1O2 molecule. For porphyrin and chlorin chemical dimers, T1 states quenching by O2 followed by 1O2 generation depends on donor-acceptor interactions between the dimer halves, and extra-ligation effects as well as the spacer flexibility. In the case of self-assembled triads and pentads containing Zn-porphyrin dimers and pyridyl substituted porphyrin free bases (H2P) as extra-ligands, quenching rate constants of H2P T1 states by O2 are smaller compared to those found for individual monomeric H2P molecules which is explained by the spatial screening influence of a strongly quenched Zn-porphyrin dimer in multiporphyrin complexes. Finally, at 293 K for nanoassemblies of two types (semiconductor quantum dots CdSe/ZnS + coordinative linked tetra-pyridyl porphyrins, and semiconductor negatively charged quantum dots AgInS/ZnS + positively charged porphyrin molecules) it was quantitatively shown that non-radiative energy transfer FRET quantum dot [Formula: see text] porphyrin (competing with electron tunneling under conditions of quantum confinement) is only responsible for the singlet oxygen 1O2 generation by nanoassemblies.

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Unique Luminescent Properties of Composition-/Size-Selected Aqueous Ag-In-S and Core/Shell Ag-In-S/ZnS Quantum Dots

Cited by 6 publications

References 158 publications

High-Throughput Time-Resolved Photoluminescence Study of Composition- and Size-Selected Aqueous Ag–In–S Quantum Dots

High-Throughput Time-Resolved Photoluminescence Study of Composition- and Size-Selected Aqueous Ag–In–S Quantum Dots

Exploring Highly Efficient Broadband Self‐Trapped‐Exciton Luminophors: from 0D to 3D Materials

Singlet oxygen generation by nanoassemblies containing porphyrin macrocycles: Steric and screening effects, energy transfer and competing processes

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