A5056634164- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Perovskite Materials and Applications
- Copper-based nanomaterials and applications
- Nanocluster Synthesis and Applications
- Advanced Photocatalysis Techniques
- 2D Materials and Applications
- Graphene research and applications
- ZnO doping and properties
- Crystal Structures and Properties
- Advanced Thermoelectric Materials and Devices
- Carbon Nanotubes in Composites
- Advanced Semiconductor Detectors and Materials
- Catalytic Processes in Materials Science
- Zeolite Catalysis and Synthesis
- TiO2 Photocatalysis and Solar Cells
- Phase-change materials and chalcogenides
- Semiconductor materials and interfaces
- Nanowire Synthesis and Applications
- Advanced Condensed Matter Physics
- Conducting polymers and applications
- Nanomaterials for catalytic reactions
- Polyoxometalates: Synthesis and Applications
- Ga2O3 and related materials
- MXene and MAX Phase Materials
Chemnitz University of Technology
2018-2024
Joint Research Center
2022
L.V. Pisarzhevskii Institute of Physical Chemistry
2016
The 2–3 nm size-selected glutathione-capped Ag–In–S (AIS) and core/shell AIS/ZnS quantum dots (QDs) were produced by precipitation/redissolution from an aqueous colloidal ensemble. QDs reveal broadband photoluminescence (PL) with a yield of up to 60% for the most populated fraction QDs. PL band shape can be described self-trapped exciton model implying being sequence phonon replica zero-phonon line resulting strong electron–phonon interaction partial conversion electron excitation energy...
Ternary luminescent copper and silver indium sulfide quantum dots (QDs) can be an attractive alternative to cadmium lead chalcogenide QDs. The optical properties of Cu-In-S Ag-In-S (AIS) QDs vary over a broad range depending on the QD composition size. implementation ternary as emitters in bio-sensing applications boosted by development mild reproducible syntheses directly aqueous solutions well methods shifting photoluminescence (PL) bands such far possible into near IR spectral range. In...
Excitation wavelength-dependent Raman spectroscopy, optical and density functional theory (DFT) calculations with hybrid functionals were used to analyse the electronic structure of defects in transparent conductive oxide SnO 2 :Ta (1.25...
A Raman spectroscopic study of Cu2ZnSnS4 (CZTS) nanocrystals (NCs) produced by a "green" synthesis in aqueous solutions is reported. Size-selected CZTS NCs reveal phonon confinement that manifests itself an upward shift the main peak about 3-4 cm-1 varying NC diameter from 3 to 2 nm. non-monotonous and narrowing are attributed special shape dispersion this material. Moreover, method sample preparation, nature supporting substrate photoexcitation regime found crucially influence spectra...
Structure, composition, and optical properties of colloidal mercaptoacetate-stabilized Cu2ZnSnS4 (CZTS) nanocrystal inks produced by a "green" method directly in aqueous solutions were characterized. A size-selective precipitation procedure using 2-propanol as non-solvent allows separating series fractions CZTS nanocrystals with an average size (bandgap) varying from 3 nm (1.72 eV) to 2 (2.04 eV). The size-selected revealed also phonon confinement, the main mode frequency about 4 cm-1 between NCs.
Ultrasmall (∼2 nm) copper(I)- and silver(I)-doped CdS core/shell CdSe/CdS quantum dots (QDs) stabilized by Cd(II) complexes with mercaptoacetate anions ammonia were produced in aqueous solutions. The doped QDs emit broadband visible photoluminescence (PL) a yield reaching 10–12% for Cu+-doped 5–9% Ag+-doped QDs. PL was described self-trapped exciton model as sequence of phonon replicas zero-phonon emission line. shape the bands CdS, QDs, modeled using energies optical phonons CuS, Ag2S,...
Abstract A straightforward, rapid method to create colloidally stable and brightly luminescent core/shell CdSe‐based nanoplatelets (NPLs) with fluorescence quantum yields (QYs) up 50% is demonstrated. layer‐by‐layer deposition technique used which based on a two‐phase mixture—consisting of nonpolar phase, includes the NPLs, saturated ionic polar phase—to separate reagents hinder nucleation shell material. The first sulfur layer leads significant redshift (by more than 100 nm) optical...
The aim of this study is to establish reliable spectroscopic fingerprints compounds that may form as secondary phases in Cu2ZnSnS4 (CZTS) nanocrystals (NCs) synthesized by “green” colloidal chemistry directly aqueous solutions or during post-processing NC films for photovoltaic applications. For purpose, we investigated a series binary and ternary compound NCs under the same conditions quaternary CZTS NCs. capabilities combined Raman X-ray photoemission (XPS) spectroscopy are used identify...
ZnO nanocrystals doped with Nd, Gd, and Er were synthesized using a soft chemical process in ambient atmosphere. Pseudospherical hexagonal (NC) of the wurtzite phase mean size (7.4 ± 1.7) nm obtained. The presence rare earth (RE) dopants was confirmed by X-ray fluorescence (XRF) spectroscopy. exhibited simultaneously narrow excitonic- broad trap/surface-related photoluminescence (PL), both which affected doping RE atoms. Doping reduced total PL intensity, suppressing excitonic emission...
Flexible temperature sensors are becoming increasingly important these days. In this work, we explore graphene oxide (GO)/poly(vinyl alcohol) (PVA) nanocomposites for potential application in sensors. The influence of the mixing ratio both materials, reduction temperature, and passivation on sensing performance has been investigated. Various spectroscopic techniques revealed composite structure atomic composition. These were complemented by semiempirical quantum chemical calculations to...
Abstract Conjugated polymers featuring tunable band gaps/positions and tailored active centers, are attractive photoelectrode materials for water splitting. However, their exploration falls far behind inorganic counterparts. Herein, we demonstrate a molecular engineering strategy the tailoring aromatic units of conjugated acetylenic from benzene‐ to thiophene‐based. The polarized thiophene‐based monomers can largely extend light absorption promote charge separation/transport. C≡C bonds...
Schematic representation of the flexible plasmonic graphene oxide (GO)/heterostructure-based device with dual functionality for electrochemical and SERS detection.
We present a detailed analysis of Raman and infrared (IR) phonon spectra strongly luminescent nonstoichiometric M–In–S (M = Cu, Ag, Hg) core/shell M–In-S/ZnS nanocrystals (NCs) small size (d ≈ 2–4 nm), formed by means aqueous colloidal chemistry under mild conditions. Despite presumably similar factors determining position broadening the X-ray diffraction (XRD) peaks, are shown to be more sensitive NC composition crystals structure. The spectral pattern these M-deficient M–In-S NCs is...
Abstract The presence of strong spin–orbit coupling in the valence band and weak spin‐splitting conduction result lowest energy exciton WX 2 (X = S, Se) being spin forbidden optically dark. Because their long lifetimes, dark excitons are highly attractive for quantum optics optoelectronic applications. To date, studying excitonic emissions is limited to cryogenic temperatures or requires very complex experimental configurations observe them at room temperature (RT). Here, radiative decay...
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 AgGaS 2 phase is less likely formed. Similarly these reveal relatively narrow indirect bandgap contrary wide and direct of . Size‐selected fractions separated repeated centrifuging...
The high chemical reactivity of epitaxial silicene on Ag(111) still remains a debated subject in the literature. In particular results oxidation and its related lifetime under ambient conditions are controversially discussed. Here, detailed investigation oxygen exposure to layers investigated by means X‐ray photoemission situ Raman spectroscopy is reported. should clearly cease discussion stability against as it becomes completely oxidized after an only 100 L oxygen. Such small dose sets...
A general synthesis approach of aqueous glutathione-capped ternary Ag–In–S, Cu–In–S, and Hg–In–S nanocrystals (NCs) is introduced, allowing the NC composition to be varied in a broad range. Ternary (HIS) NCs are reported for first time found have same tetragonal chalcopyrite motif as Cu–In–S Ag–In–S NCs, corroborated by phonon spectra, while X-ray photoelectron spectroscopic data indicate mercury present Hg+ NCs. Colloidal HIS Hg–In–S/ZnS showed little or no variations spectral width...
Highly efficient magnetic spin memory devices operating at ambient temperatures were recently realized via self-assembled molecular layers of an enantiomeric phase polyalanine (PA). However, the repeatability and yield such rely sensitively on layer quality. In this work, we grew α-l-PA (36 monomers α-amino acid, 5.4 nm) highly oriented pyrolytic graphite surfaces investigated structure by scanning tunneling microscopy under conditions liquid–solid interface, complemented X-ray photoelectron...
The effect of flash-lamp annealing (FLA) on the re-crystallization thin films made colloidal Cu2ZnSnS4 nanocrystals (NCs) is investigated by Raman spectroscopy. Unlike similar previous studies NCs synthesized at high temperatures in organic solvents, this work, which have diameters as small 2-6 nm, were under environmentally friendly conditions aqueous solution using molecules stabilizers. We establish range FLA providing an efficient film NCs, while preserving their kesterite structure and...