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Evaluation of 3D gold nanodendrite layers obtained by templated galvanic displacement reactions for SERS sensing and heterogeneous catalysis
摘要： Dense layers of overlapping three-dimensional (3D) gold nanodendrites characterized by high specific surfaces as well as by abundance of sharp edges and vertices creating high densities of SERS hotspots are promising substrates for SERS-based sensing and catalysis. We have evaluated to what extent structural features of 3D gold nanodendrite layers can be optimized by the initiation of 3D gold nanodendrite growth at gold particles rationally positioned on silicon wafers. For this purpose, galvanic displacement reactions yielding 3D gold nanodendrites were guided by hexagonal arrays of parent gold particles with a lattice constant of 1.5 μm obtained by solid-state dewetting of gold on topographically patterned silicon wafers. Initiation of the growth of dendritic features at the edges of the gold particles resulted in the formation of 3D gold nanodendrites while limitation of dendritic growth to the substrate plane was prevented. The regular arrangement of the parent gold particles supported the formation of dense layers of overlapping 3D gold nanodendrites that were sufficiently homogeneous within the resolution limits of Raman microscopy. Consequently, SERS mapping experiments revealed a reasonable degree of uniformity. The proposed preparation algorithm comprises only bottom-up process steps that can be carried out without the use of costly instrumentation.
关键词： heterogeneous catalysis,galvanic displacement reactions,3D gold nanodendrites,SERS sensing,solid-state dewetting
更新于2025-11-19 16:56:35
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - The structure of Scandium thin films on the W(100) surface observed using emission microscopy
摘要： Thermionic emission microscopy is used to observe scandium on W(100). Scandium thin films were deposited by thermal evaporation from a metal source onto W(100). The scandium films on W(100) were observed to de-wet from the W(100) surface and to form droplets when the surface is heated: the dewetting temperature is thickness dependent, and spans a range from 500 to 800 C, far below the melting temperature (1541 C). Thinner films produce smaller droplets.
关键词： thermionic,dewetting,scandium,emission,tungsten
更新于2025-09-23 15:21:21
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Semitransparent Perovskite Solar Cells
摘要： Solar cells are one of the most attractive and nonpolluting energy sources. In this field, hybrid and inorganic perovskite, which is a semiconductor, has been shown to function efficiently in the solar cell. One of the unique properties of perovskite allows it to become semitransparent—not just by controlling its optical properties. In this review we provide the most updated methods and techniques to make semitransparent perovskite solar cells: (i) the use of thin perovskite film; (ii) the possibility to self-assemble the perovskite on a photoanode, providing an empty transparent area while not sacrificing the light harvesting efficiency; (iii) the use of the solvent properties to form islands of perovskite using de-wetting on the surface; and (iv) the possibilities to form a transparent contact that makes the solar cell fully semitransparent. Finally, the potential and future features of semitransparent perovskite solar cells are presented.
关键词： Transparent Contact,Dewetting,Solar Cells,Perovskite,Thin Films,Semitransparent,Self-assembly
更新于2025-09-23 15:21:01
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Inkjet printing a small-molecule binary emitting layer for organic light-emitting diodes
摘要： For inkjet-printed organic light-emitting diodes, it is critical to obtain a homogeneous small molecular-based emitting film. In contrast to the conventional strategy of utilizing mixed solvents, we have successfully inkjet printed a binary electrophosphorescent emitter with a single solvent. The binary emitter consists of a new host material of 3-(3,6-di-t-butylcarbazol-9-yl)-3'-(2-(4-t-butylphenyl)benzoimidazol-1-yl)-[1,1'-biphenyl], and an iridium complex dopant of bis(2-methyldibenzo[f,h]quinoxaline)(acetylacetonate)- iridium(III) (Ir(MDQ)2(acac)). Compatible with Ir(MDQ)2(acac), the newly developed host is highly soluble and amorphous with a glass transition temperature of 137 oC upon cooling from the melt. The inkjet printability and film morphology of the emitting layer are strongly dependent both on substrates and the solvents. With the o-dichlorobenzene (o-DCB) as the single solvent, and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4?-(N-(p-butylphenyl))diphenylamine)] (TFB) as the hole transporting layer, a uniform emitter film morphology without any coffee ring is obtained. The phosphorescent OLEDs with the inkjet-printed emitter yields a maximum current efficiency of 17.89 cd/A, comparable to that of the Ir(MDQ)2(acac)?based OLEDs with spin-cast emitter.
关键词： Dewetting,Coffee ring,Inkjet printing,Phosphorescent OLEDs,Small molecules
更新于2025-09-23 15:21:01
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<i>In Situ</i> Characterization of the Triphase Contact Line in a Brush-Coating Process: Toward the Enhanced Efficiency of Polymer Solar Cells
摘要： Solution processes have been widely used for making polymer ?lms in organic photoelectric devices but su?er from di?culties in controlling the ?lm formation. Here, by in situ characterization triphase contact lines (TCLs) in a brush-coating process, we clarify how TCLs a?ect the quality of as-prepared ?lms. By ?ne-tuning the dewetting of a binary polymer solution (P3HT:PCBM) via di?erent directions, TCLs with di?erent patterns lead to ?lms with di?erent morphologies. High-quality nanothin ?lms with larger crystallized sizes and higher orientations were enabled when TCLs were parallel to the brush edge, based on which the polymer solar cell shows higher power conversion e?ciency (2.665%) compared with that of the spin-coated ?lm.
关键词： in situ characterization,the Chinese brush,dewetting,triphase contact line,polymer ?lms
更新于2025-09-23 15:21:01
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Antifungal Properties of Pure Silver Films with Nanoparticles Induced by Pulsed-Laser Dewetting Process
摘要： Silver particles were prepared by dewetting Ag ?lms coated on glass using a ?ber laser. The size of the particles was controlled in the range of 92 nm–1.2 μm by adjusting the thickness of the Ag ?lm. The structural properties and surface roughness of the particles were evaluated by means of scanning electron microscopy. In addition, the antifungal activity of the Ag particles was examined using spore suspensions of Colletotrichum gloeosporioides. It is shown that particles with a size of 1.2 μm achieved 100% inhibition of conidia growth of C. gloeosporioides after a contact time of just 5 min. Furthermore, the smaller particles also achieved good antifungal activity given a longer contact time. Similar results were observed for spore germination and pathogenicity tests performed on mango fruit and leaves. Overall, the results con?rm that Ag particles have an excellent antifungal e?ect on C. gloeosporioides.
关键词： colletotrichum gloeosporioides,dewetting,Ag,laser
更新于2025-09-23 15:21:01
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An In-situ Transmission X-ray Microscope to Observe the Dewetting Process of Au Thin Films induced by Nanosecond Pulsed Laser Irradiation
摘要： We coupled an in-situ transmission X-ray microscope (TXM) with a Nd:YAG pulsed laser with a 532-nm wavelength and a 6-ns pulse width. This system was employed to investigate the photo-induced morphological evolution in Au thin films during shot-by-shot irradiation by a single laser pulse. Based on results for Au thin films with thicknesses of 10 and 20 nm, we successfully demonstrated the in-situ TXM system to be a powerful tool for imaging the photo-induced transition from metal thin films to metal nanoparticles. We also found that the sequence of steps leading to this transition depended critically on the thickness of the Au films.
关键词： In-situ transmission X-ray microscope,Zernike phase contrast,Photo-induced dewetting process,Au nanoparticles
更新于2025-09-16 10:30:52
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Surface resonance properties of pure Cu and Cu80Zr20 metallic glass films with nanoparticles induced by pulsed-laser dewetting process
摘要： Pure Cu and Cu80Zr20 thin films with a thickness of 10 nm were deposited on glass substrates using a high-vacuum sputtering system. A pulsed-laser dewetting process was then performed using a NIR laser system. For the pure Cu film, nanoparticles were produced for the accumulated energy (AE) densities in the range of 0.6~11 J/cm2. The particle size was found to increase with increasing scanning speed and repetition rate, and with decreasing power. For the Cu80Zr20 thin film, nanoparticles were formed under all AE values under consideration. The nanoparticles consisted almost entirely of Cu; with the Zr atoms being repelled to the bottom of the nanoparticle and surroundings. The optical absorption peak wavelengths for the Cu and Cu80Zr20 films produced under different dewetting conditions all lay in the range of 580~700 nm. Hence, it was inferred that the nanoparticles produced in the two films had a similar size, shape and composition.
关键词： surface resonance properties,Pulsed-laser dewetting,metallic glass,nanoparticle
更新于2025-09-12 10:27:22
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Dewetting Metal Nanofilms—Effect of Substrate on Refractive Index Sensitivity of Nanoplasmonic Gold
摘要： The localized surface plasmon resonance (LSPR) sensitivity of metal nanostructures is strongly dependent on the interaction between the supporting substrate and the metal nanostructure, which may cause a change in the local refractive index of the metal nanostructure. Among various techniques used for the development of LSPR chip preparation, solid-state dewetting of nano?lms offers fast and cost effective methods to fabricate large areas of nanostructures on a given substrate. Most of the previous studies have focused on the effect of the size, shape, and inter-particle distance of the metal nanostructures on the LSPR sensitivity. In this work, we reveal that the silicon-based supporting substrate in?uences the LSPR associated refractive index sensitivity of gold (Au) nanostructures designed for sensing applications. Speci?cally, we develop Au nanostructures on four different silicon-based ceramic substrates (Si, SiO2, Si3N4, SiC) by thermal dewetting process and demonstrate that the dielectric properties of these ceramic substrates play a key role in the LSPR-based refractive index (RI) sensitivity of the Au nanostructures. Among these Si-supported Au plasmonic refractive index (RI) sensors, the Au nanostructures on the SiC substrates display the highest average RI sensitivity of 247.80 nm/RIU, for hemispherical Au nanostructures of similar shapes and sizes. Apart from the signi?cance of this work towards RI sensing applications, our results can be advantageous for a wide range of applications where sensitive plasmonic substrates need to be incorporated in silicon based optoelectronic devices.
关键词： refractive index sensitivity,metal nano?lm,localized surface plasmonic resonance,dewetting
更新于2025-09-11 14:15:04
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Dewetting of monolayer water and isopropanol between MoS2 nanosheets
摘要： Understanding dewetting of solvent molecules confined to layered material (LM) interfaces is crucial to the synthesis of two-dimensional materials by liquid-phase exfoliation. Here, we examine dewetting behavior of water and isopropanol/water (IPA/H2O) mixtures between molybdenum disulfide (MoS2) membranes using molecular dynamics (MD) simulations. We find that a monolayer of water spontaneously ruptures into nanodroplets surrounded by dry regions. The average speed of receding dry patches is close to the speed of sound in air. In contrast, monolayer mixtures of IPA/H2O between MoS2 membranes slowly transform into percolating networks of nanoislands and nanochannels in which water molecules diffuse inside and IPA molecules stay at the periphery of islands and channels. These contrasting behaviors may explain why IPA/H2O mixtures are much more effective than H2O alone in weakening interlayer coupling and exfoliating MoS2 into atomically thin sheets.
关键词： molecular dynamics simulations,liquid-phase exfoliation,isopropanol/water mixtures,two-dimensional materials,layered material interfaces,dewetting,solvent molecules,MoS2 membranes
更新于2025-09-10 09:29:36