A5090625715- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Nanocluster Synthesis and Applications
- Perovskite Materials and Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Nonlinear Optical Materials Studies
- Catalysis and Hydrodesulfurization Studies
- Advanced Photocatalysis Techniques
- Asymmetric Hydrogenation and Catalysis
- Photonic Crystals and Applications
- 2D Materials and Applications
- Supramolecular Self-Assembly in Materials
- Semiconductor Quantum Structures and Devices
- Carbon and Quantum Dots Applications
- Catalysis for Biomass Conversion
- Advanced biosensing and bioanalysis techniques
- Electrocatalysts for Energy Conversion
- Metal-Organic Frameworks: Synthesis and Applications
- Near-Field Optical Microscopy
- Pigment Synthesis and Properties
- Silicon Nanostructures and Photoluminescence
- Copper-based nanomaterials and applications
- Luminescence Properties of Advanced Materials
- Inorganic Chemistry and Materials
- GaN-based semiconductor devices and materials
TU Dresden
2022-2025
Leibniz University Hannover
2023-2025
Belarusian State University
2013-2021
National Academy of Sciences of Belarus
2020
B.I. Stepanov Institute of Physics
2020
We investigate the optical absorption properties of colloidal CdSe nanoplatelets and compare them to quantum dots. Starting from inductively coupled plasma–atomic emission spectroscopy (ICP-AES) measurements on their intrinsic coefficients μi, we these results with a theoretical approach by continuum Lorentz local field model. show that platelets' μi are strongly thickness aspect ratio dependent, which in possibility tune this material class lateral size thickness. The absorbance platelets...
We report a comprehensive study on the two-photon absorption cross sections of colloidal CdSe nanoplatelets, -rods, and -dots different sizes by means z-scan excitation spectroscopy. Platelets combine large particle volumes with ultra strong confinement. In contrast to weakly confined nanocrystals, TPA nanoplatelets scale superlinearly volume (V(∼2)) show ten times more efficient than nanorods or dots. This unexpectedly shape dependence goes well beyond effect local fields. The larger...
We study the influence of surface passivating ligands on optical and structural properties zinc blende CdSe nanoplatelets.
In this paper we present a simple method for the preparation of highly stable colloidal solutions individual nanoplatelets (NPls) with increased fluorescence quantum yield and versatile procedure NPls self-assembly into stacks controlled size. Dynamic light scattering technique has been demonstrated to be accurate in situ studies growth kinetics aggregates. The introduced work is based on exchange ligands surface CdSe nanoplatelets. Hexadecylphosphonic acid allows control average size...
We report excited state emission from p-states at excitation fluences well below ground saturation in CdSe nanoplatelets. Size dependent exciton state-excited energies and dynamics are determined by three independent methods, time-resolved photoluminescence (PL), time-integrated PL Hartree renormalized k$\cdot$p calculations -- all very good agreement. The energy spacing strongly increases with the lateral platelet quantization. Our results suggest that decay of platelets is governed an...
We present a study of the application potential CdSe nanoplatelets (NPLs), model system for colloidal 2D materials, as field-controlled emitters. demonstrate that their emission can be changed by 28% upon electrical fields up to 175 kV/cm, very high modulation depth nanoemitters. From our experimental results we estimate exciton binding energy in 5.5 monolayer EB = 170 meV; hence NPLs exhibit highly robust excitons which are stable even at room temperature. This opens possibility tune and...
A trimetallic rare-earth cluster-based metal–organic framework is synthesized that emits red, green and blue emission simultaneously.
We developed colloidal synthesis to investigate the structural and electronic properties of CdSe–CdTe inverted CdTe–CdSe heteronanoplatelets.
III-V semiconductor nanocrystals (NCs) have emerged as a viable, more benign alternative to state-of-the-art II-VI and IV-VI NCs, which are increasingly restricted due the toxicity of comprising elements. While great progress has been achieved for InP, covering visible range, development infrared-emitting InAs NCs relatively low-paced. This is synthetic challenges arising from highly covalent bonding in small choice available arsenic sources, essentially limited tris(trimethylsilyl)arsine...
We reveal for the first time temperature dependence of radiative and non-radiative lifetimes type II excitons in hetero nanoplatelets.
We investigate the impact of shell growth on carrier dynamics and exciton–phonon coupling in CdSe–CdS core–shell nanoplatelets with varying thickness. observe that recombination can be prolonged by more than one order magnitude, analyze results a global rate model as well simulations including strain excitonic effects. reveal type I band alignment hetero platelets is maintained at least up to three monolayers CdS, resulting approximately constant radiative rates. Hence, observed changes...
We show that two-photon absorption (TPA) is highly anisotropic in CdSe nanoplatelets, thus promoting them as a new class of directional absorbers with large cross sections. Comparing two-dimensional k-space spectroscopic measurements the one-photon and excitation an oriented monolayer platelets, it revealed TPA into continuum phenomenon. This contrast to absorption. The observed shown be related fundamental band anisotropies zincblende ultrastrong confinement. recover internal transition...
We investigate the spectral dependence of linear and two-photon absorption wurtzite CdS nanoparticles (dots rods) by means quantitative one- photoluminescence excitation spectroscopy effective mass theory modeling. Absolute cross sections free from spectrally varying beam related uncertainties are obtained a new reference dye-based method. The spectrum features rods strongly differ those dots, due to distinct energy structure quasi-one-dimensional systems. transversal confinement is found...
Metal-enhanced photoluminescence is able to provide a robust signal even from single emitter and promising in applications biosensors optoelectronic devices. However, its realization with semiconductor nanocrystals (e.g., quantum dots, QDs) not always straightforward due the hidden fully described interactions between plasmonic nanoparticles an emitter. Here, we demonstrate nonclassical enhancement (i.e., conventional electromagnetic mechanism) of QD at nonplasmonic conditions correlate it...
Tuning Exciton–Phonon Interaction in CdSe Nanoplatelets.
We present a method for the determination of average number polymer molecules on surface AIIBVI luminescent core–shell nanocrystals (CdSe/ZnS, ZnSe/ZnS quantum dots, and CdS/ZnS nanorods) encapsulated with amphiphilic polymer. Poly(maleic anhydride-alt-1-tetradecene) (PMAT) was quantitatively labeled amino-derivative fluorescein amount PMAT per single nanocrystal determined using optical absorption dye in visible spectral range. The grows linearly area all studied nanocrystals. However,...
Rich exciton fine structure in CdSe nanoplatelets.
Cadmium chalcogenide nanoplatelets (NPLs) are established as promising materials for a wide variety of optoelectronic applications due to their properties surpassing in many aspects counterpart nanocrystals (NCs) with other shapes. Most these features arise from strong quantum confinement the direction thickness which can be tuned precision down one monolayer. However, atomic smoothness basal planes and hence ability change NPL only discrete steps prevent precise tuning absorption...
Gradient core-shell Zn-Cu-In-S/ZnS quantum dots (QDs) of small size and with highly efficient photoluminescence were synthesized via a multi-step high-temperature method involving cation exchange. The procedure starts the preparation indium sulfide nanoparticles followed by addition Cu Zn precursors. At this stage, replaces atoms as result concentration ions in final QDs is only about 5% total In content QD. incorporation formation gradient ZnS shell dramatically increases yield....
Transition metal phosphide (TMP) nanoparticles (NPs) have emerged as a versatile material for wide array of energy conversion/storage applications due to their robustness and broad range available compositions, stoichiometries, crystalline structures. Combined with size shape control, this opens many possibilities tailor NPs’ electronic, physical, chemical properties. One the main hurdles towards broader implementation TMP NPs consists in challenging synthesis further exacerbated by limited...
In this work, fabrication of multilayers colloidal CdSe/CdS/ZnCdS core/wings/shell nanoplatelets (NPls) on solid substrates by layer-by-layer deposition technology is successfully demonstrated for the first time. Integration into polymeric waveguide resulted in strong dichroism absorption and polarization effects photoluminescence with preferable emission TE (horizontal) mode that evidences about in-plane orientation NPls relative to planar waveguide. The propagation excitation light along...
Electrochemistry of quantum dots (QDs) can provide useful information on their redox behavior and energy states. Here, we present a study the surface-limited electrochemical deposition cadmium adatoms (underpotential or upd) electrophoretically formed films CdSe QDs different sizes (2.4–6.3 nm) capped with ligands (oleate sulfide). Oleate-capped QD were shown to have weak response in upd reaction, whereas sulfide-capped demonstrated significant increase cathodic current that was attributed...