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Recent progress in laser materials processing and synthesis
摘要： Already today, high-power lasers have become indispensable for many areas of material processing such as welding, cutting, engraving or drilling. Without them, many industrial production processes are no longer possible. In the age of Industry 4.0, the integration of intelligent production systems and advanced information technologies, laser-assisted material processing, and synthesis will become even more important. Thanks to their high throughput, great precision, and efficiency as well as the excellent quality of the processed products laser-based technologies are on the way of becoming one of the most important processing and production routes of the future. By changing laser parameters such as wavelength or pulse durations many different types of materials, including metals, polymers, ceramics, and their composites can be processed. The energy required for processing can be provided in a localized volume with negligible heat transfer to the surrounding components. Due to these unique properties of lasers, new applications of the laser as a material processing tool are continuously made available. New process pathways in additive manufacturing, surface structuring, material deposition or nanoparticle synthesis are among the newer application areas of lasers.
关键词： nanoparticle synthesis,laser materials processing,laser synthesis,additive manufacturing,high-power lasers
更新于2025-09-23 15:19:57
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Cu Nanoparticle Array-Mediated III-V/Si Integration: Application in Series-Connected Tandem Solar Cells
摘要： The integration of III-V materials with crystalline Si (c-Si) is a promising pathway to design high-performance optoelectronic devices, including solar cells. We have previously reported high-efficiency III-V/Si tandem cells using our unique semiconductor bonding technique, termed smart stack. In the conventional smart stack cells, Pd nanoparticle (NP) arrays have been commonly employed as bonding mediators between III-V and c-Si; however, from an economical point of view, the use of other low-cost metals would be preferable. Therefore, this study focused on the possibility of Cu. A polystyrene-block-poly-2-vinylpyridine (PS-b-P2VP)-based block copolymer was utilized to prepare Cu NP arrays. Desired Cu NP arrays were achieved by starting with self-assembled PS-b-P2VP micelles preloaded with Cu2+ ions. Satisfying bonding properties (low-resistance interfaces) were confirmed when GaAs subcells were stacked on the Cu NP arrays formed on native oxide-removed c-Si subcells. Conversion efficiencies up to 25.9% have been demonstrated with triple-junction structures consisting of InGaP/GaAs top and c-Si bottom subcells. The long-term reliability of Cu NP array-mediated smart stack cells were also verified by the thermal cycle and damp heat tests. Hence, we have successfully confirmed that not only Pd but also Cu is available to realize high-efficiency smart stack cells.
关键词： III-V,Copper,block copolymer,solar cell,tandem,nanoparticle,silicon,self-assembly
更新于2025-09-23 15:19:57
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Metabolic mapping with plasmonic nanoparticle assemblies
摘要： A rapid and simple methodology for the biomolecular analysis of single cells and microenvironments via a stick-and-peel plasmonic sensing platform is reported. Substrate-bound assemblies of plasmonic gold nanoparticles linked by reconfigurable oligonucleotides undergo disassembly upon target binding. Changes in the light scattering intensity of thousands of discrete nanoparticle assemblies are extrapolated concomitantly to yield the mapping of local target concentrations. The methodology is completely free of labelling, purification and separation steps. We quantified the intracellular ATP levels for two ovarian cancer cell lines to elucidate the differences and cellular distribution, and demonstrated the potential of the stick-and-peel platform for mapping the microenvironment of a 2D heterogeneous surface. The portable and economical analytical platform may broaden the affordability and applicability of single-cell based analyses and enable new opportunities in clinical care such as on-site molecular pathology.
关键词： stick-and-peel platform,plasmonic nanoparticle assemblies,ATP detection,single-cell analysis,molecular pathology
更新于2025-09-23 15:19:57
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Insights into Ultrashort Laser-Driven Au:TiO <sub/>2</sub> Nanocomposite Formation
摘要： Modern methods of laser-based nanocomposite fabrication and treatment rely on a deep understanding of the interplay between a set of mechanisms involved, such as nanoparticle growth and decay, material phase transformation, degradation and damage. In this work, scanning multi-pulse femtosecond laser irradiation is used for Au : T iO2 nanocomposite formation. Depending on laser scan speed two di?erent regimes are observed revealing di?erent gold nanoparticle growth rates. The regime of the remarkably fast laser-induced growth of Au nanoparticles is found to be accompanied by the cavity formation in titania ?lm around the particles. The transition between two formation regimes is found to be abrupt con?rming the catastrophic mechanism of Au nanoparticle growth. The obtained results are analyzed based on the developed numerical model including e?ects such as nanoparticle absorption, local ?eld enhancement, photo-induced free carrier generation, plasmon-assisted electron emission, and thermal heat transfer from nanoparticles towards titania matrix. Our modeling reveals the crucial role of collective thermoplasmonic e?ects caused namely by bimodal nanoparticle size distribution. The performed analysis also suggests that spall in solid state is responsible for ?nal matrix degradation if nanoparticles become large enough. The considered laser-based formation of optical nanocomposites is crucial not only for the better understanding of ultra-short laser interactions with glass-metallic nanocomposite materials, but also for numerous applications in photocatalysts, solar cells, and chemo-sensors.
关键词： femtosecond laser,nanocomposite,thermoplasmonic effects,nanoparticle growth,Au:TiO2
更新于2025-09-23 15:19:57
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Localized Surface Plasmon Resonance-Induced Welding of Gold Nanotriangles and the Local Plasmonic Properties for Multicolor Sensing and Light-Harvesting Applications
摘要： The excitation of localized surface plasmon resonance in gold nanotriangles by continuous light illumination triggered the welding of two adjacent nanotriangles into one nanoparticle. The facing localized surface plasmon resonance generated at the corners of the gold nanotriangles facilitated welding of the nanotriangles, in which electromagnetically seamless bonding was formed. We examined the scanning transmission electron microscopy-electron energy loss spectra of the obtained nanostructure and confirmed the generation of a localized plasmon mode at the bonding spot with an energy of 2.3 eV, which did not appear in the two adjacent gold nanotriangles without bonding. The experimental electron energy loss spectra and maps were supported by the simulation data calculated using the boundary element method. An electromagnetically continuous nanostructure was successfully constructed by a site-selective welding method in this work, resulting in modulation of the localized surface plasmon resonance in nanoparticles, including the localized spots, resonant wavelength and enhancement factor. The generation of a localized surface plasmon resonance mode by welding of nanoparticles can enable multicolor sensing and light harvesting applications.
关键词： plasmon mode,site-selective welding,nanoparticle,electron energy loss spectroscopy,localized surface plasmon resonance,gold nanotriangle
更新于2025-09-23 15:19:57
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Tents, Chairs, Tacos, Kites, and Rods: Shapes and Plasmonic Properties of Singly Twinned Magnesium Nanoparticles
摘要： Nanostructures of some metals can sustain light-driven electron oscillations called localized surface plasmon resonances, or LSPRs, that give rise to absorption, scattering, and local electric field enhancement. Their resonant frequency is dictated by the nanoparticle (NP) shape and size, fueling much research geared towards discovery and control of new structures. LSPR properties also depend on composition; traditional, rare and expensive noble metals (Ag, Au) are increasingly eclipsed by earth-abundant alternatives, with Mg being an exciting candidate capable of sustaining resonances across the ultraviolet, visible, and near-infrared spectral ranges. Here, we report numerical predictions and experimental verifications of a set of shapes based on Mg NPs displaying various twinning patterns including (10 1), (10 2), (10 3) and (11 1), that create tent, chair, taco and kite-shaped NPs, respectively. These are strikingly different from what is obtained for typical plasmonic metals because Mg crystallizes in a hexagonal close packed structure, as opposed to the cubic Al, Cu, Ag, and Au. A numerical survey of the optical response of the various structures, as well as the effect of size and aspect ratio, reveals their rich array of resonances, which are supported by single particle optical scattering experiments. Further, corresponding numerical and experimental studies of the near-field plasmon distribution via scanning transmission electron microscopy electron-energy loss spectroscopy unravels a mode nature and distribution that are unlike those of either hexagonal plates or cylindrical rods. These NPs, made from earth-abundant Mg, provide interesting ways to control light at the nanoscale across the ultraviolet, visible, and near-infrared spectral ranges.
关键词： nanoplasmonics,nanoparticle shape,magnesium nanoparticles,localized surface plasmon resonance,electron-energy loss spectroscopy,Wulff construction
更新于2025-09-23 15:19:57
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Photoresponsive Structured Liquids Enabled by Molecular Recognition at Liquida??Liquid Interfaces
摘要： Using the host-guest molecular recognition at the oil-water interface, a new-type photo-responsive nanoparticle surfactant (NPS), is designed and prepared to structure liquids. With the help of a polymeric surfactant, the interfacial host-guest interactions can be significantly enhanced, leading to a rapid formation and assembly of a NP monolayer, and offering sufficient binding energy to hold the NPs in a jammed state. The assembly of the NPSs can be reversibly manipulated via a photo-switchable jamming to unjamming transition, endowing the interface, as well as the macroscopic assemblies, with responsiveness to the external trigger (photons). This study, for the first time, opens the pathway for the construction of multi-responsive, structured all-liquid systems by introducing host?guest chemistry, showing promising potential applications in encapsulation, delivery systems, and unique microfluidic devices.
关键词： self-assembly,liquid-liquid interfaces,host-guest chemistry,Structured liquid,nanoparticle surfactants
更新于2025-09-23 15:19:57
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Silicon nanoparticle generation and deposition on glass from waste silicon powder by nanosecond pulsed laser irradiation
摘要： Silicon nanoparticles can be used for fabricating electrodes in high-performance lithium ion batteries and other high value-added products. Currently, silicon nanoparticles are fabricated by pulsed laser irradiation of single-crystal silicon wafers in water. In this study, we proposed silicon nanoparticle generation by using a nanosecond pulsed laser to irradiate waste silicon powder which is disposed from wire-saw slicing processes of silicon ingots. The laser-induced nanoparticles were backward-transferred and deposited on a glass substrate. It was found that the morphology and amount of the deposited nanoparticles was strongly dependent on the distance between the glass substrate and the waste silicon powder target. Raman spectroscopy showed that the silicon nanoparticles were crystalline, and the average size was ~10 nm. The obtained silicon nanoparticles had high purity, as the diamond abrasives included in the waste silicon powder were removed through oxidation and vaporization during laser irradiation.
关键词： Raman spectroscopy,Silicon crystal,Waste silicon powder,Nanoparticle,Nanosecond pulsed laser
更新于2025-09-23 15:19:57
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Efficiency Improvement of MAPbI3 Perovskite Solar Cells Based on a CsPbBr3 Quantum Dot/Au Nanoparticle Composite Plasmonic Light-Harvesting Layer
摘要： We demonstrate a method to enhance the power conversion efficiency (PCE) of MAPbI3 perovskite solar cells through localized surface plasmon (LSP) coupling with gold nanoparticles:CsPbBr3 hybrid perovskite quantum dots (AuNPs:QD-CsPbBr3). The plasmonic AuNPs:QD-CsPbBr3 possess the features of high light-harvesting capacity and fast charge transfer through the LSP resonance effect, thus improving the short-circuit current density and the fill factor. Compared to the original device without Au NPs, a 27.8% enhancement in PCE of plasmonic AuNPs:QD-CsPbBr3/MAPbI3 perovskite solar cells was achieved upon 120 μL Au NP solution doping. This improvement can be attributed to the formation of surface plasmon resonance and light scattering effects in Au NPs embedded in QD-CsPbBr3, resulting in improved light absorption due to plasmonic nanoparticles.
关键词： quantum dot,perovskite solar cell,CaPbBr3,Au nanoparticle,localized surface plasmon
更新于2025-09-23 15:19:57
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Nanoparticle enhanced laser ablation and consequent effects on laser induced plasma optical emission
摘要： In this paper the plasmon enhanced ablation for elemental analysis is investigated with several experiments in order to point out the crucial questions concerning the laser matter interaction under the effect of plasmonic coupling between the nanoparticle (NP) system and the laser ablation pulse. The correlation between the electromagnetic field enhancement and the signal enhancement during NP enhanced laser induced breakdown spectroscopy (NELIBS), as well as the laser matter interaction at the nanoscale, is discussed in the case of noble metal NPs deposited on metal samples. The results suggest that, while laser pulse energy is concentrated in the space between the NPs, the NP system is shielded by the field enhancement distribution after the laser pulse interacts with the plasmons of the NP system. Finally the comparison of the laser energy transfer to the sample between NELIBS and conventional LIBS is discussed.
关键词： LIBS,Nanoparticle enhanced laser induced breakdown spectroscopy (NELIBS),laser ablation,plasmonic enhanced ablation,LA-ICP-MS
更新于2025-09-23 15:19:57