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Science China(Physics,Mechanics & Astronomy) 2022年第7期65卷 118-120页

作者： S.Reichenberger university of duisburg-essen Center for Nanointegration Duisburg-Essen(CENIDE)Duisburg 47057Germany Technical ChemistryⅠ University of Duisburg-EssenEssen 45141Germany

Throughout more than a decade, the surfactant-free laser synthesis and processing of nanoparticles(LSPC) have become an established and scalable synthesis method to provide libraries of high-purity nanoparticles with different sizes and elemental compositions [1-3] ranging from single elemental metals [2,3] and oxides [1] to binary and multinary[2,3] and even multinary high entropy alloys [4].

关键词： laser defect purity

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Laser-generated high entropy metallic glass nanoparticles as bifunctional electrocatalysts

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Nano Research 2022年第6期15卷 4807-4819页

作者： Jacob Johny Yao Li Marius Kamp Oleg Prymak Shun-Xing Liang Tobias Krekeler Martin Ritter Lorenz Kienle Christoph Rehbock Stephan Barcikowski Sven Reichenberger Technical Chemistry I and center for nanointegration duisburg-essen(cenide) University of Duisburg-EssenEssen 45141Germany Institute for Materials Science Synthesis and Real StructureKiel UniversityKiel 24143Germany Inorganic Chemistry and center for nanointegration duisburg-essen(cenide) University of Duisburg-EssenEssen 45141Germany Electron Microscopy Unit Hamburg University of TechnologyHamburg 21073Germany

High entropy metallic glass nanoparticles(HEMG NPs)are very promising materials for energy conversion due to the wide tuning possibilities of electrochemical potentials offered by their multimetallic character combined with an amorphous *** until now,the generation of these HEMG NPs involved tedious synthesis procedures where the generated particles were only available on highly specialized supports,which limited their widespread ***,more flexible synthetic approaches to obtain colloidal HEMG NPs for applications in energy conversion and storage are highly *** utilized pulsed laser ablation of bulk high entropy alloy targets in acetonitrile to generate colloidal carbon-coated CrCoFeNiMn and CrCoFeNiMnMo HEMG *** in-depth analysis of the structure and elemental distribution of the obtained nanoparticles down to single-particle levels using advanced transmission electron microscopy(TEM),energy-dispersive X-ray spectroscopy(EDX),X-ray diffraction(XRD),and Xray photoelectron spectroscopy(XPS)methods revealed amorphous quinary and senary alloy phases with slight manganese oxide/hydroxide surface segregation,which were stabilized within graphitic *** on the catalytic activity of the corresponding carbon-HEMG NPs during oxygen evolution and oxygen reduction reactions revealed an elevated activity upon the incorporation of moderate amounts of Mo into the amorphous alloy,probably due to the defect generation by atomic size ***,we demonstrate the superiority of these carbon-HEMG NPs over their crystalline analogies and highlight the suitability of these amorphous multi-elemental NPs in electrocatalytic energy conversion.

关键词： high entropy alloy pulsed laser ablation in liquid amorphous catalysis oxygen evolution reaction oxygen reduction reaction

Plasma and nanoparticle shielding during pulsed laser ablation in liquids cause ablation efficiency decrease

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Opto-Electronic Advances 2021年第1期4卷 1-13页

作者： Sarah Dittrich Stephan Barcikowski Bilal Gökce Technical Chemistry I and center of nanointegration duisburg essen(cenide) University of Duisburg-EssenUniversitaetsstr.745141 EssenGermany

Understanding shielding cross-effects is a prerequisite for maximal power-specific nanosecond laser ablation in liquids(LAL).However,discrimination between cavitation bubble(CB),nanoparticle(NP),and shielding,e.g.,by the plasma or a transient vapor layer,is ***,CB imaging by shadowgraphy is performed to better understand the plasma and laser beam-NP interaction during *** comparing the fluence-dependent CB volume for ablations performed with 1 ns pulses with reports from the literature,we find larger energy-specific CB volumes for 7 *** increased CB for laser ablation with higher ns pulse durations could be a first explanation of the efficiency decrease reported for these laser systems having higher pulse ***,1 ns-LAL shows superior ablation ***,a CB cascade occurs when the focal plane is shifted into the *** effect is enhanced when NPs are present in the *** minute amounts of NPs trapped in a stationary layer decrease the laser energy significantly,even under liquid ***,this local concentration in the sticking film has so far not been *** presents an essential obstacle in high-yield LAL,shielding already the second laser pulse that arrives and presenting a source of satellite ***,measures to lower the NP concentration on the target must be investigated in the future.

关键词： shadowgraphy power-specific productivity flow dynamics ablation mechanism

Advances in pulsed laser synthesis of nanoparticles in liquids

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Science China(Physics,Mechanics & Astronomy) 2022年第7期65卷 1-2页

作者： A.Ziefuss S.Barcikowski L.V.Zhigilei Department of Technical Chemistry Ⅰ and center for nanointegration duisburg-essen cenide University of Duisburg-Essen Department of Materials Science and Engineering University of Virginia

Certainly, when Richard Feynman outlined his vision of the prospects of nanotechnology in 1959 with his legendary speech“There is Plenty of Room at the Bottom”, no one would have thought of where we are today, only 60 years later. In the 21 st century, nanoparticles(NPs) are found almost everywhere and are pervasive in science, technology, and our everyday lives.

关键词： laser everyday nanoparticles

Spatially Resolved Photoelectric Performance of Axial GaAs Nanowire pn-Diodes

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Nano Research 2011年第10期4卷 987-995页

作者： Andrey Lysov Sasa Vinaji Matthias Offer Christoph Gutsche Ingo Regolin Wolfgang Mertin Martin Geller Werner Prost Gerd Bacher Franz-Josef Tegude center for nanointegration duisburg-essen University of Duisburg-Essen 47048 Duisburg Germany

The spatially resolved photoelectric response of a single axial GaAs nanowire pn-diode has been investigated with scanning photocurrent and Kelvin probe force microscopy. Optical generation of carriers at the pn-junction has been shown to dominate the photoresponse. A photocurrent of 88 pA, an open circuit voltage of 0.56 V and a fill factor of 69% were obtained under AM 1.5 G conditions. The photocurrent followed the increasing photoexcitation with 0.24 A/W up to an illumination density of at least 90 W/cm2, which is important for potential applications in concentrator solar cells.

关键词： GaAs nanowire solar cells scanning photocurrent microscopy Kelvin probe force microscopy electroluminescence

Standard-state entropies and their impact on the potential-dependent apparent activation energy in electrocatalysis

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Journal of Energy Chemistry 2023年第8期83卷 247-254,I0008页

作者： Kai S.Exner Universty duisburg-essen Faculty of ChemstryTheretical Inorganic ChemtryUniversitatsstrae 545141 EssenGemay Cluster of Excellence RESOLV 44801 BochumGermany center for nanointegration(cenide)duisburg-essen 47057 DuisburgGermany

The apparent activation energy,Eapp,is a common measure in thermal catalysis to discuss the activity and limiting steps of catalytic processes on solid-state ***,the electrocatalysis community adopted the concept of Eappand combined it with the Butler-Volmer *** observations though,such as potential-dependent fluctuations of Eapp,are yet surprising because they conflict with the proposed linear decrease in Eappwith increasing *** most common explanation for this finding refers to coverage changes upon alterations in the temperature or the applied electrode *** the present contribution,it is demonstrated that the modulation of surface coverages cannot entirely explain potential-dependent oscillations of Eapp,and rather the impact of entropic contributions of the transition states has been overlooked so *** the case of a nearly constant surface coverage,these entropic contributions can be extracted by a dedicated combination of Tafel plots and temperature-dependent experiments.

关键词： Electrocatalysis Standard-state entropy Microkinetic modeling Apparent activation energy Degree of rate control

Combining descriptor-based analyses and mean-field modeling of the electrochemical interface to comprehend trends of catalytic processes at the solid/liquid interface

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Journal of Energy Chemistry 2023年第10期85卷 288-290,I0009页

作者： Kai S.Exner university duisburg-essen Faculty of ChemistryTheoretical Inorganic ChemistryUniversitätsstraße 545141 EssenGermany Cluster of Excellence RESOLV 44801 BochumGermany center for nanointegration(cenide)duisburg-essen 47057 DuisburgGermany

Electrocatalysis is undergoing a renaissance due to its central importance for a sustainable energy economy,relying on green(electro-)chemical processes to harvest,convert,and store *** considerations by electronic structure methods are key to identify potential material motifs for electrocatalytic processes at the solid/liquid *** commonly,heuristic concepts in the realm of materials screening by the compilation of volcano plots are used,which rely on a plethora of simplifications and approximations of the complex electrochemical *** the investigation of the catalytic processes at the solid/liquid interface mainly relies on descriptor-based approaches,in the present future article it is discussed that the inclusion of the liquid part of the interface by mean-field models is crucial to elevate screening approaches to the next level.

关键词： Electrocatalysis Volcano plot Descriptor approach Electrochemical interface Mean-field model

Inversion of electrical mobility measurements using bipolar or unipolar chargers for the arbitrary distribution of channels

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Particuology 2015年第3期13卷 114-123页

作者： M.Domat F.E.Kruis N.L.Azong-Wara J.M.Fernandez-Diaz Department of Physics University of OviedoC/Calvo Sotelos/nE-33007 OviedoSpain Institute of Technology for Nanostructures(NST) and center for nanointegration duisburg-essen(cenide) University of Duisburg-EssenBismarckstr.81D-47057 DuisburgGermany

The inversion of the particle size distribution from electrical mobility measurements is analyzed. Three different methods are adapted for a dot-matrix approach to the problem, especially for non-square or singular matrices, and applied to electrical mobility measurements from fixed or scanning voltages. Mul- tiply charged particles, diffusion losses, arbitrary voltage steps and noise were considered, which results in non-adjoining and overlapping transfer functions. The individual contribution of the transfer func- tions in each size interval was geometrically estimated, which requires only its characteristic mobilities. The methodology is applied to mobility measurements from particles charged with unipolar and bipolar chargers. However, the method can be extrapolated to any charging method with a defined charge distribution, and retrieval of the singly charged particle distribution and mean charge from a tandem differential mobility analysis configuration was successfully demonstrated.

关键词： Tandem differential mobility analysisInverse problemRegularization methodsSize distributionTransfer functionUnipolar charger

Multidimensional thermally-induced transformation of nest-structured complex Au-Fe nanoalloys towards equilibrium

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Nano Research 2022年第1期15卷 581-592页

作者： Jacob Johny Oleg Prymak Marius Kamp Florent Calvo Se-Ho Kim Anna Tymoczko Ayman El-Zoka Christoph Rehbock Ulrich Schurmann Baptiste Gault Lorenz Kienle Stephan Barcikowski Technical Chemistry I and center for nanointegration duisburg-essen(cenide) University of Duisburg-EssenEssen 45141Germany Inorganic Chemistry and center for nanointegration duisburg-essen(cenide) University of Duisburg-EssenEssen 45141Germany Institute for Materials Science Synthesis and Real StructureKiel UniversityKiel 24143Germany university Grenoble Alpes CNRSLiPhyGrenoble 38000France Max-Planck-Institut fur Eisenforschurtg GmbH Diisseldorf40237Germany Department of Materials Royal School of MineImperial College LondonLondon SW72AZUK

Bimetallic nanoparticles are often superior candidates for a wide range of technological and biomedical applications owing to their enhanced catalytic,optical,and magnetic properties,which are often better than their monometallic *** of their properties strongly depend on their chemical composition,crystallographic structure,and phase ***,little is known of how their crystal structure,on the nanoscale,transforms over time at elevated temperatures,even though this knowledge is highly relevant in case nanoparticles are used in,e.g.,high-temperature ***-Fe is a promising bimetallic system where the low-cost and magnetic Fe is combined with catalytically active and plasmonic ***,we report on the in s/fi;temporal evolution of the crystalline ordering in Au-Fe nanoparticles,obtained from a modern laser ablation in liquids *** in-depth analysis,complemented by dedicated atomistic simulations,includes a detailed structural characterization by X-ray diffraction and transmission electron microscopy as well as atom probe tomography to reveal elemental distributions down to a single atom *** show that the Au-Fe nanoparticles initially exhibit highly complex internal nested nanostructures with a wide range of compositions,phase distributions,and size-depended *** elevated temperature induces a diffusion-controlled recrystallization and phase merging,resulting in the formation of a single face-centered-cubic ultrastructure in contact with a body-centered cubic phase,which demonstrates the metastability of these *** these unique nanostructures with nested features could be highly attractive from a fundamental viewpoint as they could give further insights into the nanoparticle formation mechanism under non-equilibrium ***,the in situ evaluation of the crystal structure changes upon heating is potentially relevant for high-temperature process utilization of bimetallic na

关键词： nanoparticles in situ atom probe tomography diffusion recrystallization atomistic simulation

Laser-based in situ embedding of metal nanoparticles into bioextruded alginate hydrogel tubes enhances human endothelial cell adhesion

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Nano Research 2016年第11期9卷 3407-3427页

作者： Andreas Blaeser Nina Million Daniela Filipa Duarte Campos Lisa Gamrad Marius Kopf Christoph Rehbock Milen Nachev Bernd Sures Stephan Barcikowski Horst Fischer Department of Dental Materials and Biomaterials Research RWTH Aachen University Hospital Pauwelsstr. 30 52074 Aachen Germany Technical Chemistry I and center for nanointegration duisburg-essen (cenide) University of Duisburg-Essen Universitatsstr. 5-7 45141 Essen Germany Aquatic Ecology University of Duisburg-Essen Universitatsstr. 5 45141 Essen Germany center for Water and Environmental Research University of Duisburg-Essen Universitatsstr. 5 45141 Essen Germany

Alginate is a widely used hydrogel in tissue engineering owing to its simple and non-cytotoxic gelation process, ease of use, and abundance. However, unlike hydrogels derived from mammalian sources such as collagen, alginate does not contain cell adhesion Iigands. Here, we present a novel laser ablation technique for the in situ embedding of gold and iron nanoparticles into hydrogels. We hypothesized that integration of metal nanoparticles in alginate could serve as an alternative material because of its chemical biofunctionalization ability （coupling of RGD ligands） to favor cell adhesion. Cytocompatibility and biofunctionality of the gels were assessed by cell culture experiments using fibroblasts and endothelial cells. Nanoparticles with an average particle size of 3 nm （gold） and 6 nm （iron） were generated and stably maintained in alginate for up to 6 months. Using an extrusion system, several centimeter-long alginate tubes with an outer diameter of approximately 3 mm and a wall thickness of approximately 150 μm were manufactured. Confocal microscopy revealed homogeneously distributed nanoparticle agglomerates over the entire tube volume. Endothelial cells seeded on iron-loaded gels showed significantly higher viability and an increased degree of spreading, and the number of attached cells was also elevated in comparison to the control and gold-loaded alginates. We conclude that laser-based in situ integration of iron nanoparticles （40.01 wt.%） in alginate is a straightforward method to generate composite materials that favor the adhesion of endothelial cells. In addition, we show that nanoparticle integration does not impair the alginate＇s gelation and 3D biofabrication properties.

关键词： biofabrication tissue engineering HUVEC nanocomposite laser ablation confocal microscopy additive manufacturing