8.
T Schröder, M B Scheible, F Steiner, J Vogelsang, P Tinnefeld
Interchromophoric Interactions Determine the Maximum Brightness Density in DNA Origami Structures Journal Article
In: Nano Letters, vol. 19, no. 2, pp. 1275-1281, 2019, ISSN: 1530-6984.
@article{,
title = {Interchromophoric Interactions Determine the Maximum Brightness Density in DNA Origami Structures},
author = {T Schr\"{o}der and M B Scheible and F Steiner and J Vogelsang and P Tinnefeld},
url = {https://doi.org/10.1021/acs.nanolett.8b04845},
doi = {10.1021/acs.nanolett.8b04845},
issn = {1530-6984},
year = {2019},
date = {2019-02-13},
urldate = {2019-02-13},
journal = {Nano Letters},
volume = {19},
number = {2},
pages = {1275-1281},
abstract = {An ideal point light source is as small and as bright as possible. For fluorescent point light sources, homogeneity of the light sources is important as well as that the fluorescent units inside the light source maintain their photophysical properties, which is compromised by dye aggregation. Here we propose DNA origami as a rigid scaffold to arrange dye molecules in a dense pixel array with high control of stoichiometry and dye\textendashdye interactions. In order to find the highest labeling density in a DNA origami structure without influencing dye photophysics, we alter the distance of two ATTO647N dyes in single base pair steps and probe the dye\textendashdye interactions on the single-molecule level. For small distances strong quenching in terms of intensity and fluorescence lifetime is observed. With increasing distance, we observe reduced quenching and molecular dynamics. However, energy transfer processes in the weak coupling regime still have a significant impact and can lead to quenching by singlet-dark-state-annihilation. Our study fills a gap of studying the interactions of dyes relevant for superresolution microscopy with dense labeling and for single-molecule biophysics. Incorporating these findings in a 3D DNA origami object will pave the way to bright and homogeneous DNA origami nanobeads.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
An ideal point light source is as small and as bright as possible. For fluorescent point light sources, homogeneity of the light sources is important as well as that the fluorescent units inside the light source maintain their photophysical properties, which is compromised by dye aggregation. Here we propose DNA origami as a rigid scaffold to arrange dye molecules in a dense pixel array with high control of stoichiometry and dye–dye interactions. In order to find the highest labeling density in a DNA origami structure without influencing dye photophysics, we alter the distance of two ATTO647N dyes in single base pair steps and probe the dye–dye interactions on the single-molecule level. For small distances strong quenching in terms of intensity and fluorescence lifetime is observed. With increasing distance, we observe reduced quenching and molecular dynamics. However, energy transfer processes in the weak coupling regime still have a significant impact and can lead to quenching by singlet-dark-state-annihilation. Our study fills a gap of studying the interactions of dyes relevant for superresolution microscopy with dense labeling and for single-molecule biophysics. Incorporating these findings in a 3D DNA origami object will pave the way to bright and homogeneous DNA origami nanobeads.
7.
J Fichtner, B Garlyyev, S Watzele, H A El-Sayed, J N Schwämmlein, W-J Li, F M Maillard, L Dubau, J Michalička, J M Macak, A W Holleitner, A S Bandarenka
Top-Down Synthesis of Nanostructured Platinum–Lanthanide Alloy Oxygen Reduction Reaction Catalysts: PtxPr/C as an Example Journal Article
In: ACS Applied Materials & Interfaces, vol. 11, no. 5, pp. 5129-5135, 2019, ISSN: 1944-8244.
@article{,
title = {Top-Down Synthesis of Nanostructured Platinum\textendashLanthanide Alloy Oxygen Reduction Reaction Catalysts: PtxPr/C as an Example},
author = {J Fichtner and B Garlyyev and S Watzele and H A El-Sayed and J N Schw\"{a}mmlein and W-J Li and F M Maillard and L Dubau and J Michali\v{c}ka and J M Macak and A W Holleitner and A S Bandarenka},
url = {https://doi.org/10.1021/acsami.8b20174},
doi = {10.1021/acsami.8b20174},
issn = {1944-8244},
year = {2019},
date = {2019-02-06},
journal = {ACS Applied Materials \& Interfaces},
volume = {11},
number = {5},
pages = {5129-5135},
abstract = {The oxygen reduction reaction (ORR) is of great interest for future sustainable energy conversion and storage, especially concerning fuel cell applications. The preparation of active, affordable, and scalable electrocatalysts and their application in fuel cell engines of hydrogen cars is a prominent step toward the reduction of air pollution, especially in urban areas. Alloying nanostructured Pt with lanthanides is a promising approach to enhance its catalytic ORR activity, whereby the development of a simple synthetic route turned out to be a nontrivial endeavor. Herein, for the first time, we present a successful single-step, scalable top-down synthetic route for Pt\textendashlanthanide alloy nanoparticles, as witnessed by the example of Pr-alloyed Pt nanoparticles. The catalyst was characterized by high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and photoelectron spectroscopy, and its electrocatalytic oxygen reduction activity was investigated using a rotating disk electrode technique. PtxPr/C showed ∼3.5 times higher [1.96 mA/cm2Pt, 0.9 V vs reversible hydrogen electrode (RHE)] specific activity and ∼1.7 times higher (0.7 A/mgPt, 0.9 V vs RHE) mass activity compared to commercial Pt/C catalysts. On the basis of previous findings and characterization of the PtxPr/C catalyst, the activity improvement over commercial Pt/C originates from a lattice strain introduced by the alloying process.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The oxygen reduction reaction (ORR) is of great interest for future sustainable energy conversion and storage, especially concerning fuel cell applications. The preparation of active, affordable, and scalable electrocatalysts and their application in fuel cell engines of hydrogen cars is a prominent step toward the reduction of air pollution, especially in urban areas. Alloying nanostructured Pt with lanthanides is a promising approach to enhance its catalytic ORR activity, whereby the development of a simple synthetic route turned out to be a nontrivial endeavor. Herein, for the first time, we present a successful single-step, scalable top-down synthetic route for Pt–lanthanide alloy nanoparticles, as witnessed by the example of Pr-alloyed Pt nanoparticles. The catalyst was characterized by high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and photoelectron spectroscopy, and its electrocatalytic oxygen reduction activity was investigated using a rotating disk electrode technique. PtxPr/C showed ∼3.5 times higher [1.96 mA/cm2Pt, 0.9 V vs reversible hydrogen electrode (RHE)] specific activity and ∼1.7 times higher (0.7 A/mgPt, 0.9 V vs RHE) mass activity compared to commercial Pt/C catalysts. On the basis of previous findings and characterization of the PtxPr/C catalyst, the activity improvement over commercial Pt/C originates from a lattice strain introduced by the alloying process.
6.
T Wu, Y Luo, S A Maier, L Wei
Phase-matching and Peak Nonlinearity Enhanced Third-Harmonic Generation in Graphene Plasmonic Coupler Journal Article
In: Physical Review Applied, vol. 11, no. 1, pp. 014049, 2019.
@article{,
title = {Phase-matching and Peak Nonlinearity Enhanced Third-Harmonic Generation in Graphene Plasmonic Coupler},
author = {T Wu and Y Luo and S A Maier and L Wei},
url = {https://link.aps.org/doi/10.1103/PhysRevApplied.11.014049},
doi = {10.1103/PhysRevApplied.11.014049},
year = {2019},
date = {2019-01-24},
journal = {Physical Review Applied},
volume = {11},
number = {1},
pages = {014049},
abstract = {Strong nonlinear optical effects generally require giant optical fields interacting with the nonlinear media. Doped graphene hosts electrically tunable plasmons with long lifetimes that interact strongly with light. We investigate a graphene plasmonic coupler and explore two mechanisms to pursue highly efficient third-harmonic generation (THG): (1) phase matching of graphene plasmons at fundamental- and third-harmonic frequencies and (2) peak third-order nonlinear susceptibility of doped graphene. The third-harmonic wave is mainly converted from the evanescent mode of the incident light and the THG efficiency is found to be enhanced by over 10 orders of magnitude compared with a bare monolayer graphene. The significantly enhanced nonlinear optical responses in the graphene plasmonic coupler make this configuration an ideal platform for the development of alternative frequency generators and for signal processing at midinfrared and terahertz frequencies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Strong nonlinear optical effects generally require giant optical fields interacting with the nonlinear media. Doped graphene hosts electrically tunable plasmons with long lifetimes that interact strongly with light. We investigate a graphene plasmonic coupler and explore two mechanisms to pursue highly efficient third-harmonic generation (THG): (1) phase matching of graphene plasmons at fundamental- and third-harmonic frequencies and (2) peak third-order nonlinear susceptibility of doped graphene. The third-harmonic wave is mainly converted from the evanescent mode of the incident light and the THG efficiency is found to be enhanced by over 10 orders of magnitude compared with a bare monolayer graphene. The significantly enhanced nonlinear optical responses in the graphene plasmonic coupler make this configuration an ideal platform for the development of alternative frequency generators and for signal processing at midinfrared and terahertz frequencies.
5.
J Li, E Tan, N Keller, Y-H Chen, P M Zehetmaier, A C Jakowetz, T Bein, P Knochel
Cobalt-Catalyzed Electrophilic Aminations with Anthranils: An Expedient Route to Condensed Quinolines Journal Article
In: Journal of the American Chemical Society, vol. 141, no. 1, pp. 98-103, 2019, ISSN: 0002-7863.
@article{,
title = {Cobalt-Catalyzed Electrophilic Aminations with Anthranils: An Expedient Route to Condensed Quinolines},
author = {J Li and E Tan and N Keller and Y-H Chen and P M Zehetmaier and A C Jakowetz and T Bein and P Knochel},
url = {https://doi.org/10.1021/jacs.8b11466},
doi = {10.1021/jacs.8b11466},
issn = {0002-7863},
year = {2019},
date = {2019-01-09},
journal = {Journal of the American Chemical Society},
volume = {141},
number = {1},
pages = {98-103},
abstract = {The reaction of various organozinc pivalates with anthranils provides anilines derivatives, which cyclize under acidic conditions providing condensed quinolines. Using alkenylzinc pivalates, electron-rich arylzinc pivalates or heterocyclic zinc pivalates produces directly the condensed quinolines of which several structures belong to new heterocyclic scaffolds. These N-heterocycles are of particular interest for organic light emitting diodes with their high photoluminescence quantum yields and long exciton lifetimes as well as for hole-transporting materials in methylammonium lead iodide perovskites solar cells due to an optimal band alignment for holes and a large bandgap.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The reaction of various organozinc pivalates with anthranils provides anilines derivatives, which cyclize under acidic conditions providing condensed quinolines. Using alkenylzinc pivalates, electron-rich arylzinc pivalates or heterocyclic zinc pivalates produces directly the condensed quinolines of which several structures belong to new heterocyclic scaffolds. These N-heterocycles are of particular interest for organic light emitting diodes with their high photoluminescence quantum yields and long exciton lifetimes as well as for hole-transporting materials in methylammonium lead iodide perovskites solar cells due to an optimal band alignment for holes and a large bandgap.
4.
M Rück, A S Bandarenka, F Calle-Vallejo, A Gagliardi
Oxygen Reduction Reaction: Rapid Prediction of Mass Activity of Nanostructured Platinum Electrocatalysts Journal Article
In: The Journal of Physical Chemistry Letters, vol. 9, no. 15, pp. 4463-4468, 2018.
@article{nokey,
title = {Oxygen Reduction Reaction: Rapid Prediction of Mass Activity of Nanostructured Platinum Electrocatalysts},
author = {M R\"{u}ck and A S Bandarenka and F Calle-Vallejo and A Gagliardi},
url = {https://doi.org/10.1021/acs.jpclett.8b01864},
doi = {10.1021/acs.jpclett.8b01864},
year = {2018},
date = {2018-07-20},
urldate = {2018-07-20},
journal = {The Journal of Physical Chemistry Letters},
volume = {9},
number = {15},
pages = {4463-4468},
abstract = {Tailored Pt nanoparticle catalysts are promising candidates to accelerate the oxygen reduction reaction (ORR) in fuel cells. However, the search for active nanoparticle catalysts is hindered by the laborious effort of experimental synthesis and measurements. On the other hand, density functional theory-based approaches are still time-consuming and often not efficient. In this study, we introduce a computational model which enables rapid catalytic activity calculation of unstrained pure Pt nanoparticle electrocatalysts. Regarding particle size effects on Pt nanoparticles, experimental catalytic mass activities from previous studies are accurately reproduced by our computational model. Moreover, beyond available experiments, our computational model identifies potential enhancement in mass activity up to 190% over the experimentally detected maximum. Importantly, the rapid activity calculation enabled by our computational model may pave the way for extensive nanoparticle screening to expedite the search for improved electrocatalysts.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Tailored Pt nanoparticle catalysts are promising candidates to accelerate the oxygen reduction reaction (ORR) in fuel cells. However, the search for active nanoparticle catalysts is hindered by the laborious effort of experimental synthesis and measurements. On the other hand, density functional theory-based approaches are still time-consuming and often not efficient. In this study, we introduce a computational model which enables rapid catalytic activity calculation of unstrained pure Pt nanoparticle electrocatalysts. Regarding particle size effects on Pt nanoparticles, experimental catalytic mass activities from previous studies are accurately reproduced by our computational model. Moreover, beyond available experiments, our computational model identifies potential enhancement in mass activity up to 190% over the experimentally detected maximum. Importantly, the rapid activity calculation enabled by our computational model may pave the way for extensive nanoparticle screening to expedite the search for improved electrocatalysts.
3.
A Kuhn, O Gerbig, C Zhu, F Falkenberg, J Maier, B V Lotsch
A new ultrafast superionic Li-conductor: ion dynamics in Li11Si2PS12 and comparison with other tetragonal LGPS-type electrolytes Journal Article
In: Physical Chemistry Chemical Physics, vol. 16, no. 28, pp. 14669-14674, 2014, ISSN: 1463-9076.
@article{nokey,
title = {A new ultrafast superionic Li-conductor: ion dynamics in Li11Si2PS12 and comparison with other tetragonal LGPS-type electrolytes},
author = {A Kuhn and O Gerbig and C Zhu and F Falkenberg and J Maier and B V Lotsch},
url = {http://dx.doi.org/10.1039/C4CP02046D},
doi = {10.1039/C4CP02046D},
issn = {1463-9076},
year = {2014},
date = {2014-05-23},
journal = {Physical Chemistry Chemical Physics},
volume = {16},
number = {28},
pages = {14669-14674},
abstract = {We report on a new ultrafast solid electrolyte of the composition Li11Si2PS12, which exhibits a higher room-temperature Li ion diffusivity than the present record holder Li10GeP2S12. We discuss the high-pressure synthesis and ion dynamics of tetragonal Li11Si2PS12, and comparison is made with our investigations of related members of the LMePS family, i.e. electrolytes of the general formula Li11−xMe2−xP1+xS12 with Me = Ge, Sn : Li10GeP2S12, Li7GePS8, Li10SnP2S12. The structure and dynamics were studied with multiple complementary techniques and the macroscopic diffusion could be traced back to fast Li ion hopping in the crystalline lattice. A clear correlation between the diffusivity and the unit cell volume of the LGPS-type electrolytes was observed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report on a new ultrafast solid electrolyte of the composition Li11Si2PS12, which exhibits a higher room-temperature Li ion diffusivity than the present record holder Li10GeP2S12. We discuss the high-pressure synthesis and ion dynamics of tetragonal Li11Si2PS12, and comparison is made with our investigations of related members of the LMePS family, i.e. electrolytes of the general formula Li11−xMe2−xP1+xS12 with Me = Ge, Sn : Li10GeP2S12, Li7GePS8, Li10SnP2S12. The structure and dynamics were studied with multiple complementary techniques and the macroscopic diffusion could be traced back to fast Li ion hopping in the crystalline lattice. A clear correlation between the diffusivity and the unit cell volume of the LGPS-type electrolytes was observed.
2.
R Natālija, B Andreas, I Hristo, W Rafał
Sub-20-attosecond timing jitter from a mode-locked 200-MHz All-PM Er:NALM fiber laser Proceedings Article
In: Proc.SPIE, pp. 128650L, 0000.
@inproceedings{nokey,
title = {Sub-20-attosecond timing jitter from a mode-locked 200-MHz All-PM Er:NALM fiber laser},
author = {R Nat\={a}lija and B Andreas and I Hristo and W Rafa\l},
url = {https://doi.org/10.1117/12.2692373},
doi = {10.1117/12.2692373},
booktitle = {Proc.SPIE},
volume = {12865},
pages = {128650L},
abstract = {Our research team has achieved a significant milestone by generating pulses with sub-20-attosecond (as) timing jitter from a 200-MHz all-Polarization-Maintaining (PM) erbium-doped (Er:) Nonlinear Amplifying Loop Mirror (NALM) fiber laser. Accurate measurement of these temporal fluctuations was conducted using the Balanced Optical cross-Correlation (BOC) technique. Through comprehensive investigation, we identified the critical parameters responsible for timing jitter, including dispersion and pump power, and validated their impact. The fine-tuning of the contributing factors allowed us to demonstrate an exceptionally low integrated timing jitter of only 15.59 attoseconds, integrated from 10 kHz to 10 MHz. This accomplishment stands as the lowest value ever documented for any free-running mode-locked fiber lasers that are erbium-doped.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Our research team has achieved a significant milestone by generating pulses with sub-20-attosecond (as) timing jitter from a 200-MHz all-Polarization-Maintaining (PM) erbium-doped (Er:) Nonlinear Amplifying Loop Mirror (NALM) fiber laser. Accurate measurement of these temporal fluctuations was conducted using the Balanced Optical cross-Correlation (BOC) technique. Through comprehensive investigation, we identified the critical parameters responsible for timing jitter, including dispersion and pump power, and validated their impact. The fine-tuning of the contributing factors allowed us to demonstrate an exceptionally low integrated timing jitter of only 15.59 attoseconds, integrated from 10 kHz to 10 MHz. This accomplishment stands as the lowest value ever documented for any free-running mode-locked fiber lasers that are erbium-doped.
1.
J Rojas, Z Wang, F Liu, J A Fereiro, D Chryssikos, T Dittrich, D Leister, D Cahen, M Tornow
Current Rectification Via Photosystem I Monolayers Induced by Their Orientation on Hydrophilic Self-Assembled Monolayers on Titanium Nitride Proceedings Article
In: 2024 IEEE 24th International Conference on Nanotechnology (NANO), pp. 266-271, 0000, ISBN: 1944-9380.
@inproceedings{nokey,
title = {Current Rectification Via Photosystem I Monolayers Induced by Their Orientation on Hydrophilic Self-Assembled Monolayers on Titanium Nitride},
author = {J Rojas and Z Wang and F Liu and J A Fereiro and D Chryssikos and T Dittrich and D Leister and D Cahen and M Tornow},
doi = {10.1109/NANO61778.2024.10628956},
isbn = {1944-9380},
booktitle = {2024 IEEE 24th International Conference on Nanotechnology (NANO)},
pages = {266-271},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}