A5101460747- Silicon Nanostructures and Photoluminescence
- Protein Structure and Dynamics
- Quantum Dots Synthesis And Properties
- Hemoglobin structure and function
- Boron and Carbon Nanomaterials Research
- Spectroscopy and Quantum Chemical Studies
- Diamond and Carbon-based Materials Research
- Carbon Nanotubes in Composites
- Semiconductor materials and devices
- Photoreceptor and optogenetics research
- Nanowire Synthesis and Applications
- Lipid Membrane Structure and Behavior
- ZnO doping and properties
- Carbon and Quantum Dots Applications
- Protein Interaction Studies and Fluorescence Analysis
- Silicon Carbide Semiconductor Technologies
- Force Microscopy Techniques and Applications
- Chalcogenide Semiconductor Thin Films
- Ion-surface interactions and analysis
- Molecular Sensors and Ion Detection
- Photosynthetic Processes and Mechanisms
- Biotin and Related Studies
- 2D Materials and Applications
- Laser-Ablation Synthesis of Nanoparticles
- Copper Interconnects and Reliability
HUN-REN Wigner Research Centre for Physics
2014-2021
Institute for Solid State Physics and Optics
2014-2019
Hungarian Academy of Sciences
2014-2019
Budapest University of Technology and Economics
2012-2014
University of Debrecen
1975-1990
We identify the exact microscopic structure of G photoluminescence center in silicon by first principles calculations with including a self-consistent many-body perturbation method, which is telecommunication wavelength single photon source. The defect constitutes $\text{C}_\text{s}\text{C}_\text{i}$ carbon impurities its $\text{C}_\text{s}-\text{Si}_\text{i}-\text{C}_\text{s}$ configuration neutral charge state, where $s$ and $i$ stand for respective substitutional interstitial positions Si...
Molecule-sized fluorescent emitters are much sought-after to probe biomolecules in living cells. We demonstrate here by time-dependent density functional calculations that the experimentally achievable 1–2 nm sized silicon carbide nanocrystals can emit light near-infrared region after introducing appropriate color centers them. These luminescent may act as ideal fluorophores for vivo bioimaging.
Understanding the fluorescence of complex systems such as small nanocrystals with various surface terminations in solution is still a scientific challenge. Here we show that combination advanced time-resolved spectroscopy and ab initio simulations, aided by engineering, able to identify luminescence centers systems. Fluorescent water-soluble silicon carbide (SiC) have been previously identified molecular silicon, carbon, oxygen, hydrogen held together covalent bonds made identification their...
Multiple Exciton Generation (MEG) in nanoparticle-based solar cells promises to increase the cell-efficiency above Shockley–Queisser limit. However, utilizing MEG is hampered by Quantum Confinement Dilemma (QCD): quantum confinement advantageously increases effective Coulomb interaction, but at same time disadvantageously electronic gap. Using ab initio calculations we showed that germanium nanoparticles with core structures of high pressure phases bulk Ge can transcend QCD, simultaneously...
Silicon carbide quantum dots in the size range of 1–10 nm are center interest with unique properties that makes them very promising biomarkers. A central requirement for this application is control over complex structure surface to enable further functionalization processes, which crucial drug delivery. In paper, a temperature-dependent infrared and photoluminescence spectroscopy study, combined ab initio modeling, presented order reveal chemical transformations termination groups. We found...
Cubic boron phosphide (BP) is an indirect band gap semiconductor with a of 2.0 eV and promising for highly stable photocatalyst to produce hydrogen from water under visible light irradiation. Here, we performed comprehensive study on the energy-level structure photocatalytic activity BP nanocrystals (NCs) in quantum confinement regime (<5 nm diameter). First, calculated electronic cubic NCs up 2.8 diameter, hexagonal nanoflakes, cubic/hexagonal nanostructures by density functional theory...
We present a time-dependent density functional theory (TDDFT) study of the optical gaps light-emitting nanomaterials, namely, pristine and heavily B- P-codoped silicon crystalline nanoparticles. Twenty DFT exchange-correlation functionals sampled from best currently available inventory such as hybrids range-separated are benchmarked against ultra-accurate quantum Monte Carlo results on small model Si nanocrystals. Overall, found to perform best. The quality is correlated with deviation...
The application of silicon nanoparticles (Si NPs) is very promising in various emerging technologies and for fundamental quantum studies semiconductor nanocrystals. Heavily boron phosphorus codoped fluorescent Si NPs can be fabricated with diameters a few nanometers. However, little understood about the structure origin fluorescence these NPs. In this work, we perform systematic time-dependent density functional study hundreds representing millions configurations. We identify most stable...
We employ time-dependent photoluminescence (PL) and steady-state PL excitation (PLE) measurements to study the size-dependent optical properties of ultrasmall silicon carbide (SiC) nanoparticles (NPs). find that nature transition transforms from solid-state indirect gap molecular-like as diameter spherical SiC NPs is reduced 4–6 1–3 nm with a smooth in between. deduce radiative lifetimes are well supported by ab initio density functional theory calculations on realistically large realistic...
Co-doped silicon nanoparticles (NPs) are promising for the realization of novel biological and optoelectronic applications. Despite scientific technological interest, structure heavily co-doped Si NPs is still not very well understood. By means first principles simulations, various spectroscopic quantities can be computed compared to corresponding experimental data. In this paper, we demonstrate that calculated infrared spectra, photoluminescence Raman spectra provide valuable insights into...
Relatively little is known about the transition metal defects in silicon carbide (SiC). In this study we applied highly convergent and sophisticated density functional theory (DFT) based methods to investigate important impurities including titanium (Ti), vanadium (V), niobium (Nb), chromium (Cr), molybdenum (Mo) tungsten (W) cubic 3C hexagonal 4H 6H polytypes of SiC. We found two classes among considered impurities: Ti, V Cr clearly prefer Si-substituting configuration while W, Nb, Mo may...
Molecule-sized fluorescent emitters are much sought-after to probe biomolecules in living cells. We demonstrate here by time-dependent density functional calculations that the experimentally achievable 1-2 nm sized silicon carbide nanocrystals can emit light nearinfrared region after introducing appropriate color centers them. These near-infrared luminescent may act as ideal fluorophores for vivo bioimaging.