Article
Chemistry, Multidisciplinary
Andrew B. Pun, Aniket S. Mule, Jacob T. Held, David J. Norris
Summary: The research team successfully grew thin CdS shells on CdSe MSNC cores via high-temperature synthesis, dramatically improving the emissive properties of the MSNCs. Thicker CdS shells result in decreased performance, but CdxZn1-xS alloyed shells maintain efficient and narrow emission lines.
Article
Materials Science, Multidisciplinary
Nobutomo Nakamura, Koji Matsuura, Akio Ishii, Hirotsugu Ogi
Summary: The formation process of core-shell bimetallic nanoparticles synthesized by sputtering onto a substrate was observed in real time using an acoustic technique. The experiments revealed that restructuring occurred in the Pd-Au alloy system, resulting in the formation of A-shell/B-core nanoparticles, while other systems tended to form B-shell/A-core nanoparticles.
Article
Materials Science, Multidisciplinary
Jianhua Zhang, Fangzhi Mou, Shaowen Tang, Joshua E. Kauffman, Ayusman Sen, Jianguo Guan
Summary: This study proposes a design of chemically-powered micromotors that actively perform multimodal motion behaviors with changing external stimuli. The micromotors have isotropic outer surfaces and inherent inner mass asymmetry, allowing them to transform their motion behavior among random Brownian propulsion, negative phototaxis, and negative photogravitaxis. The behaviors depend on changes in light intensity, illumination direction, or fuel concentration.
APPLIED MATERIALS TODAY
(2022)
Article
Chemistry, Multidisciplinary
El yakout El Koraychy, Riccardo Ferrando
Summary: We simulated the formation of Cu@Au core@shell nanoparticles by depositing gold on preformed seeds and studied the effect of the shape and composition of the starting seed on the growth pathway. Our results show that the shape and composition of the seed have significant effects on the growth pathways of Cu@Au core@shell nanoparticles.
Article
Chemistry, Multidisciplinary
Sandip Aryal, Durga Paudyal, Ranjit Pati
Summary: Incorporating features of antiferromagnet into a semiconductor core-shell nanowire opens up new possibilities in spintronics. Quantum mechanical prediction shows that Cr-doped nanowire behaves as an antiferromagnetic semiconductor with longer spin coherence length and high ON/OFF current ratio switching feature. This material presents potential for applications in spin-dependent quantum transport.
Article
Chemistry, Physical
Shijia Zeng, Zhenbo Li, Wenjiang Tan, Jinhai Si, Yuren Li, Xun Hou
Summary: The hole transfer process from the core to the surface in InP/ZnS and InP/ZnSe/ZnS quantum dots was studied comparatively using ultrafast spectroscopy and time-resolved photoluminescence technology. The results show that InP/ZnSe/ZnS quantum dots have a faster hole transfer rate with a ZnSe midshell thickness of about 2.2 nm. This is because the ZnSe midshell increases the density of higher-energy hole states, allowing a larger proportion of photoexcited holes to be distributed in these states compared to InP/ZnS quantum dots. The easier hole transfer in these higher-energy states makes InP/ZnSe/ZnS quantum dots more suitable for photoelectric conversion systems than InP/ZnS quantum dots.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Materials Science, Multidisciplinary
Zdenek Weiss, Petr Ashcheulov, Nicolas Lambert, Andrew Taylor, Jan Lorincik, Kil-dong Sung, Marina Davydova, Vincent Mortet
Summary: Boron- and phosphorus-doped diamond layers were analyzed using glow discharge optical emission spectroscopy. A methodology for quantitative depth profiling based on multi-matrix calibration was developed, assuming matrix-independent emission yields. The accuracy and sensitivity of the analysis were discussed. The analysis of boron showed satisfactory performance using the B I line at 208.959 nm. However, the analysis of phosphorus was affected by an argon-related interference, which could be eliminated by using neon discharge, resulting in an eightfold improvement in the phosphorus detection limit. The analysis also revealed a light interference effect in transparent layers, indicating their transparency in the ultraviolet region.
Article
Chemistry, Multidisciplinary
Alexander J. Touchton, Guang Wu, Trevor W. Hayton
Summary: This study successfully isolated a nickel-based atomically precise nanocluster (APNC), which is the largest open-shell nickel APNC to date. SQUID magnetometry reveals that this nanocluster possesses a manifold of closely-spaced electronic states near the HOMO-LUMO gap. In situ monitoring by ESI-MS and P-31{H-1} NMR spectroscopy shows that the nanocluster forms via the intermediacy of smaller APNCs.
Article
Chemistry, Physical
Linwei Sai, Xue Wu, Fengyu Li
Summary: A highly symmetric core-shell structure B-96 with good stability at high temperatures has been designed and studied. It exhibits superatomic electronic configuration and spherical aromaticity. The theoretical work not only confirms the energetic advantage of the core-shell structure for large-sized boron clusters, but also provides a strategy for designing large boron clusters with high symmetry core-shell structures.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Jan Vanbuel, Piero Ferrari, Meiye Jia, Andre Fielicke, Ewald Janssens
Summary: The interaction of argon with doubly transition metal doped aluminum clusters was studied experimentally and theoretically. It was found that the argon affinity of the clusters depends on the transition metal dopant, and a pronounced drop in reactivity was observed at a certain cluster size regardless of the dopant element. The analysis of cluster orbitals suggests that this change in reactivity is electronic in nature rather than due to cage formation.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Shi-Xiong Li, Yue-Ju Yang, De-Liang Chen
Summary: A theoretical study on a new kind of nonmetallic atom-doped boron cluster is presented. The addition of a phosphorus atom to the B-12 motif results in the formation of a novel B-12 cage, composed of two B-3 rings at both ends and one B-6 ring in the middle, forming a triangular bifrustum. Further addition of two phosphorus atoms leads to the formation of a triangular bipyramid structure. The structures exhibit D-3h symmetry and provide a theoretical basis for future experimental investigations.
Article
Materials Science, Multidisciplinary
Muchuan Hua, Ricardo S. Decca
Summary: This study investigated the possibility of optical refrigeration on zinc-blende CdSe/CdS core/shell structure quantum dots and developed a semiempirical model to predict the feasibility of optical refrigeration on a CdSe QD system.
Article
Materials Science, Ceramics
Ning Liu, Tengfei Hu, Jingxian Zhang, Duan Yusen, Zhen Wang, Shaoming Dong
Summary: Si3N4 ceramics are attractive casing materials for electronics devices under the 5th generation mobile communication technology due to their outstanding comprehensive properties. However, a single color is insufficient for most consumers. Therefore, a typical strategy involving the formation of core-shell structures using the Nd2O3-MgO-YAG system is proposed to achieve rich color. Scanning transmission electron microscope-energy dispersive X-ray spectrometry results confirm the presence of core-shell structures in the silicon nitride matrix, with a porous core and an Nd-enriched liquid phase shell. The Nd-rich core-shell structure acts as a color center, giving the silicon nitride a cyan or blue appearance.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Physical
Nejc Nagelj, Alexandra Brumberg, Shoshanna Peifer, Richard D. Schaller, Jacob H. Olshansky
Summary: This study introduces a method to control the thermodynamic driving force for photoexcited charge transfer in quantum dots (QDs) and investigates the electron transfer rates using functionalized QDs. The findings contribute to optimizing charge transfer systems by maximizing the electron transfer rate while minimizing energetic losses.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Daniel Boas, Sergei Remennik, Meital Reches
Summary: We have developed a short peptide consisting of only six amino acids that can simultaneously reduce Au3+ or Ag+ ions and stabilize the resulting nanoparticles. The peptide-capped nanoparticles demonstrated a fast, selective, and pH-dependent detection system for Hg2+, Mn2+, and Fe2+ ions. In addition, the peptide-mediated photoreduction process successfully enveloped gold nanoparticles with a silver shell, resulting in bimetallic Au@Ag core/shell nanoparticles.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Instruments & Instrumentation
T. Tanikawa, S. Karabekyan, S. Kovalev, S. Casalbuoni, V Asgekar, S. Bonetti, S. Wall, T. Laarmann, D. Turchinovich, P. Zalden, T. Kampfrath, A. S. Fisher, N. Stojanovic, M. Gensch, G. Geloni
JOURNAL OF SYNCHROTRON RADIATION
(2020)
Article
Materials Science, Multidisciplinary
Mahesh Namboodiri, Cheng Luo, Gregor Indorf, Torsten Golz, Ivanka Grguras, Jan H. Buss, Michael Schulz, Robert Riedel, Mark J. Prandolini, Tim Laarmann
Summary: This study estimated the optical properties of mid-infrared, Li-based nonlinear crystals under realistic experimental conditions for high power lasers using the thermal imaging method. The research focused on crystals with large apertures for broad spectral range applications and provided estimates of linear and nonlinear absorption coefficients, as well as the nonlinear refractive index for certain crystals, for the first time. These optical material properties are crucial for cutting-edge laser developments near damage thresholds in long-wavelength mid-infrared spectral range.
OPTICAL MATERIALS EXPRESS
(2021)
Article
Nanoscience & Nanotechnology
Calvin J. Brett, Wiebke Ohm, Bjorn Fricke, Alexandros E. Alexakis, Tim Laarmann, Volker Korstgens, Peter Muller-Buschbaum, L. Daniel Soderberg, Stephan Roth
Summary: The combination of nanocellulose and silver can be used to fabricate large-area optically responsive materials for organic optoelectronics. Research shows the potential to tailor the energy band gap of the resulting hybrid material.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Optics
S. Hartwell, A. Azima, C. Haunhorst, M. Kazemi, M. Namboodiri, A. Przystawik, D. Schwickert, S. Skruszewicz, D. Kip, M. Drescher, T. Laarmann
Summary: Controlling the temporal and spectral properties of ultrashort laser pulses in the visible and near-infrared spectral range using a femtosecond pulse-shaping device is a powerful tool with many applications. The 4f design, known for its symmetric zero-dispersion-compressor geometry, is a major and successful concept. An all-reflective shaping setup is used in this study to generate a phase-locked 266 nm double pulse, with time-frequency spectra in good agreement with optical simulations.
APPLIED PHYSICS B-LASERS AND OPTICS
(2022)
Article
Optics
S. Skruszewicz, A. Przystawik, D. Schwickert, M. Sumfleth, M. Namboodiri, V Hilbert, R. Klas, P. Gierschke, V Schuster, A. Vorobiov, C. Haunhorst, D. Kip, J. Limpert, J. Rothhardt, T. Laarmann
Summary: This contribution presents a high-precision XUV pulse autocorrelator for short-pulse metrology and dynamic studies, demonstrating its performance in characterizing electronic transitions in argon gas. The results are compared with a high-resolution XUV grating spectrometer, showing excellent agreement and opening up new opportunities for femtosecond and attosecond pulse metrology and dynamic studies in various research fields.
Article
Optics
Daniel Uhl, Andreas Wituschek, Ulrich Bangert, Marcel Binz, Carlo Callegari, Michele Di Fraia, Oksana Plekan, Kevin Charles Prince, Giulio Cerullo, Luca Giannessi, Miltcho Danailov, Giuseppe Sansone, Tim Laarmann, Rupert Michiels, Marcel Mudrich, Paolo Piseri, Richard James Squibb, Raimund Feifel, Stefano Stranges, Frank Stienkemeier, Lukas Bruder
Summary: Interferometric pump-probe experiments in the extreme ultraviolet (XUV) domain are challenging due to the need for high phase stability. A recent study introduced an efficient phase stabilization scheme for seeded XUV free electron lasers (FELs) and extended the scheme to stabilize the XUV beam path, improving the signal quality compared to previous methods.
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
David Schwickert, Marco Ruberti, Premysl Kolorenc, Sergey Usenko, Andreas Przystawik, Karolin Baev, Ivan Baev, Markus Braune, Lars Bocklage, Marie Kristin Czwalinna, Sascha Deinert, Stefan Duesterer, Andreas Hans, Gregor Hartmann, Christian Haunhorst, Marion Kuhlmann, Steffen Palutke, Ralf Roehlsberger, Juliane Roensch-Schulenburg, Philipp Schmidt, Sven Toleikis, Jens Viefhaus, Michael Martins, Andre Knie, Detlef Kip, Vitali Averbukh, Jon P. Marangos, Tim Laarmann
Summary: In this study, x-rays are used to create and probe quantum coherence in the photoionized amino acid glycine. The researchers observe the coherent superposition of quantum mechanical eigenstates and the evolution of electronic coherence through delayed x-ray pulses. The experiment provides direct evidence for long-lived electronic coherence in photoionized biomolecules.
Article
Chemistry, Physical
Daniel Uhl, Andreas Wituschek, Rupert Michiels, Florian Trinter, Till Jahnke, Enrico Allaria, Carlo Callegari, Miltcho Danailov, Michele Di Fraia, Oksana Plekan, Ulrich Bangert, Katrin Dulitz, Friedemann Landmesser, Moritz Michelbach, Alberto Simoncig, Michele Manfredda, Simone Spampinati, Giuseppe Penco, Richard James Squibb, Raimund Feifel, Tim Laarmann, Marcel Mudrich, Kevin C. Prince, Giulio Cerullo, Luca Giannessi, Frank Stienkemeier, Lukas Bruder
Summary: Femtosecond extreme ultraviolet wave packet interferometry (XUV-WPI) was used to study resonant interatomic Coulombic decay (ICD) in the HeNe dimer. By utilizing an XUV phase-cycling scheme, the high demands on phase stability and sensitivity for vibronic XUV-WPI of molecular-beam targets were met. The experiment demonstrated vibronic dephasing and rephasing signatures, ultrafast decoherence related to the ICD process, and high-resolution molecular absorption spectrum. This study provides a promising method for real-time analysis of ultrafast ICD processes with high temporal and spectral resolution.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Klaus von Haeften, Tim Laarmann, Hubertus Wabnitz, Thomas Moeller
Summary: The relaxation dynamics of electronically excited He-3 and He-4 clusters and droplets are studied using NIR/VIS fluorescence excitation spectroscopy. A rich data set is obtained, revealing distinct cluster size and isotope dependence in the normalized spectra. Particle density and atomic-like states' principal quantum number (n) are found to be crucial factors in the relaxation process. Energy transfer, ejection, and fluorescence mechanisms differ for different atomic states and droplet sizes.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Malte Sumfleth, Andreas Przystawik, Mahesh Namboodiri, Tim Laarmann
Summary: XUV fluorescence spectroscopy provides information on energy absorption and dissipation processes in the interaction of helium clusters with intense femtosecond laser pulses. The results support previous findings and highlight the important role of Rydberg states in the energetics and dynamics of laser-generated nanoplasma.
NEW JOURNAL OF PHYSICS
(2023)
Proceedings Paper
Electrochemistry
Mihail Petev, Torsten Golz, Jan Heye Buss, Michael Schulz, Slawomir Skruszewicz, Andreas Przystawik, Tim Laarmann, Thorsten Uphues, Atiqa Arshad, Jan C. Deinert, Robert Riedel
Summary: This article presents a versatile high repetition rate optical-parametric chirped-pulse amplifier system, coupled with a high-harmonic-generation source. By tuning the driver wavelength, high harmonic generation can be achieved in the range of 25 to 50 eV, allowing for control and tuning of all energies between adjacent odd harmonics. This makes the system a powerful and gaplessly tunable extreme-ultraviolet light source for spectroscopy.
NONLINEAR FREQUENCY GENERATION AND CONVERSION: MATERIALS AND DEVICES XXI
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Mahesh Namboodiri, Torsten Golz, Jan H. Buss, Michael Schulz, Robert Riedel, T. Laarmann, Mark J. Prandolini
Summary: A review of the thermal parameters of Li-based nonlinear crystals is presented, showing preliminary results of an 8 μm laser system at 200 kHz with 2 μJ pulse energy and a Fourier limit of under 100 fs.
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Mahesh Namboodiri, Cheng Luo, Torsten Golz, Jan H. Buss, Michael Schulz, Robert Riedel, Tim Laarmann, Mark J. Prandolini
Summary: A high power MID-IR laser system with tunable pulses in the range of 4.2-11 μm and a maximum pulse energy of 2.2 μJ has been developed using an OPCPA with a DFG stage, supporting high repetition rates and ultrafast dynamics studies with a Fourier limit of 50 fs. Thermal parameters of various nonlinear crystals are also reviewed for potential use in high power MID-IR OPCPAs.
NONLINEAR FREQUENCY GENERATION AND CONVERSION: MATERIALS AND DEVICES XX
(2021)
Article
Optics
Viktoriia Savchenko, Faris Gel'mukhanov, Tim Laarmann, Sergey P. Polyutov, Victor Kimberg
Summary: Through theoretical study, we found that the relative phase shift of coherent x-ray double pulses can result in a modulation of spectra that is shifted with respect to the phase oscillation comb. This shift is determined by the dynamics of the process defined by the interplay of delay time, pulse width, detuning, and core-excited state lifetime.