Electrical Property of Laser-Sintered Nanopastes with Reduced Metal Nanoparticles Prepared by Laser Ablation in Liquids
TL;DR: In this paper, the laser-sintered metal nanopastes were analyzed by SEM and EDX, and their resistivities were evaluated by four-terminal method, and the results showed that they have 2.5-to 11-times higher resistivities than those of common metals fabricated in blast furnaces.
Abstract: Reduced iron, aluminum, copper, and magnesium nanoparticles were produced from iron oxide (Fe3O4), aluminum oxide (Al2O3), copper oxide (CuO), and magnesium oxide (MgO) powders by using laser ablation in liquids, and nanopastes were synthesized with the reduced iron, aluminum, copper, and magnesium nanoparticles. The nanopastes were sintered by using a continuous-wave fiber laser in air atmosphere. The laser-sintered nanopastes consist of polycrystalline metal. The structures of the laser-sintered metal nanopastes were analyzed by SEM and EDX, and their resistivities were evaluated by four-terminal method. The metal nanopastes sintered by hot plate have 2.5- to 11-times-higher resistivities than those of common metals fabricated in blast furnaces. Moreover, the laser-sintered metal nanopastes have 9.5- to 45-times-higher resistivities than those of common metals fabricated in blast furnaces.
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Cites methods from "Electrical Property of Laser-Sinter..."
...We also investigated application of these inexpensive metal nanoparticles in printed electronics, and so on [12]....
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TL;DR: In this paper, the authors investigated the possibility of reducing metal oxide in a metal by using high-voltage pulses in order to save electrical consumption power compared with conventional methods that use high-temperature and high-pressure plasma such as arc discharge.
Abstract: Metal nanoparticles have become attractive as original materials for nano-inks and nano-pastes, which are used in printed electronics. Synthesizing various metal nanoparticles has been researched. We investigated the possibility of reducing metal oxide in a metal by using high-voltage pulses in this paper. This method should save electrical consumption power compared with conventional methods that use high-temperature and high-pressure plasma such as arc discharge. Reduced Al nanoparticles were obtained by applying high-voltage pulses to solutions. By analyzing elements and the composition of reduced Al nanoparticles by STEM and EDX, a large amount of reduced Al nanoparticles with diameters of a few 100 nm and thin oxide film of around 1 nm on metal surfaces were produced in experiments for reducing Al oxide. It was found from hydrogen generation using reduced Al nanoparticles by applying high-voltage pulses to solutions to evaluate reduction rate that a high reduction efficiency of 97% was obtained at maximum. We concluded that using high-voltage pulses for reduction can be suitably applied to printed electronics because the oxide film on reduced Al nanoparticles is thin. Also, because this method is similar to laser ablation in liquids using pulse lasers, the similarities were discussed in this paper.
2 citations
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TL;DR: In this article, the reduction in the skin effect for the sintered Si nanopolycrystalline body as an electricity conductor at a high frequency due to its nano-structure was studied.
Abstract: Reduction in the skin effect for the sintered Si nanopolycrystalline body as an electricity conductor at a high frequency due to its nano-structure was studied. Singular vanishing of electrical resistances near a local high magnetic harmonic frequency of a few MHz was observed. This phenomenon has not been observed for conventional ferromagnetic metals. The measured electrical resistances changed to almost 0 m{\Omega} at room temperature. At the same time, negative resistance of the sintered Si nano-polycrystalline body was observed. It will be applicable to electronic transmittance lines or semiconductors. Numerical calculation was also performed on the electrical resistance with frequency dependency while considering the electric field and magnetic field in the sintered Si nanopolycrystalline body. The calculation could explain the variation of the relative permittivity of the Si nanopolycrystalline and the phenomenon for vanishing the resistivity at frequency of MHz theoretically. Reduced Si nanoparticles from SiO2 powder were synthesized by laser ablation in liquid. A Si nano-polycrystalline body made of the reduced Si nanoparticles was fabricated. It was found by measuring the magnetization property of the body that the sintered Si nano-polycrystalline body has ferromagnetism. High-density dangling bonds cause the sintered Si nanopolycrystalline to have ferromagnetism. In this study, the density of the unpaired electrons in the sintered Si nanopolycrystalline was observed using ESR. It has been clarified that the Si nanopowder and the sintered Si nanopolycrystalline have numerous dangling bonds. Both densities of the dangling bonds were evaluated.
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TL;DR: In this article, the reduction in the skin effect for the sintered Si nanopolycrystalline body as an electricity conductor at a high frequency due to its nanostructure was studied.
Abstract: Reduction in the skin effect for the sintered Si nanopolycrystalline body as an electricity conductor at a high frequency due to its nanostructure was studied. Singular disappearance of electrical resistances near a local high magnetic harmonic frequency of a few MHz was observed. This phenomenon has not been observed for conventional ferromagnetic metals. The measured electrical resistances changed to almost 0 mΩ at room temperature. At the same time, negative resistance of the sintered Si nanopolycrystalline body was observed. It will be applicable to electronic transmittance lines or semiconductors. Numerical calculation was also performed on the electrical resistance with frequency dependency while considering the electric field and magnetic field in the sintered Si nanopolycrystalline body. The experimental and calculated results are compared. The calculation could explain the variation of the relative permittivity of the Si nanopolycrystalline body and the phenomenon for the theoretical disappearance of the resistivity at the MHz frequency. Reduced Si nanoparticles from SiO2 powder were synthesized by laser ablation in liquid. A Si nanopolycrystalline body made of the reduced Si nanoparticles was fabricated. It was found by measuring the magnetization property of the body of the sintered Si nanopolycrystalline body which is ferromagnetic. Dangling bonds (unpaired electrons) have long been known to occur due to defects in Si crystals. Perfect Si without defective crystals has no dangling bonds. However, Si nanoparticles have many dangling bonds. High-density dangling bonds cause the sintered Si nanopolycrystalline body to have ferromagnetism. In this study, the density of the unpaired electrons in the sintered Si nanopolycrystalline body was observed using ESR. It has been clarified that the Si nanopowder and the sintered Si nanopolycrystalline body have numerous dangling bonds. Both densities of the dangling bonds were evaluated.
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References
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TL;DR: In this paper, inkjet-printed Cu nanoparticle structures were sintered on a polyimide substrate with a continuous-wave 808-nm diode laser, and the electrical resistance of the samples was measured.
Abstract: Copper is an interesting
material for printed electronics inks because, for example, of its good
conductivity and lower raw material price compared to silver. However,
post-processing Cu inks is challenging because of non-conductive copper oxide.
In this work, inkjet-printed Cu nanoparticle structures were sintered on a
polyimide substrate with a continuous-wave 808-nm diode laser. Laser sintering
was tested by varying the sintering parameters (optical power and scanning
velocity), and the electrical resistance of the samples was measured. A minimum
sheet resistance of approx.90 mΩ/□
was obtained. All tests were run in room conditions. Sintered structures were
then analyzed from SEM images. Results showed that laser sintering produces
good repeatability, that a scanning velocity increment positively affects the
process window, and that multiple sintering cycles do not increase
conductivity.
33 citations
"Electrical Property of Laser-Sinter..." refers background or methods in this paper
...Co pper nanoparticle ink or copper nanopastes sintered by l aser with low resistivity can be produced under a narrow lase r-int nsity regime [5] or a reducing atmosphere by using nitrog en as [4]....
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...Moreover, copper nanopa rticle ink or copper nanopastes oxidize easily under sinte ring, and the sintered metals have high resistivities [5]....
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...These pastes, however, are expensive, so c opper nanopaste or copper-nanoparticle inks (which are lo wer cost) have been researched [4-6]....
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TL;DR: The 1064 nm nanosecond laser-induced fragmentative decomposition of fine CuO powder in acetone, at the laser fluence of typically ∼ 1 J/cm2, generated ∼10 nm Cu nanoparticles (NPs) at the production rate, ∼ 1 mg/min, for the input laser power of only ∼ 0.5 W as discussed by the authors.
Abstract: The 1064 nm nanosecond laser-induced fragmentative decomposition of fine CuO powder in acetone, at the laser fluence of typically ∼1 J/cm2, generated ∼10 nm Cu nanoparticles (NPs) at the production rate, ∼1 mg/min, for the input laser power of only ∼0.5 W. This highly productive laser synthesis of CuNPs is also characterized by a large conversion yield (≥80%) from CuO powder to CuNPs, as achieved by sufficiently prolonged laser irradiation. They underwent rapid aerobic oxidation preferentially to Cu2O NPs, which are equally useful material for conductive pattern making. In whatever oxidation states, they also exhibited superior dispersivity in ketone solvents with neither intentional nor unintentional protective shell. The 1064 nm laser interaction of fine CuO powder is characterized by relatively small light absorption efficiency as compared to that in the visible region, which rather helps in preventing excess and/or nonuniform laser heating of each particle. Spectroscopic analysis of the laser-induced ...
27 citations
"Electrical Property of Laser-Sinter..." refers background in this paper
...Metal oxides have already been reduced a t low cost by using a pulsed laser with a high peak power in liquids [7-15]....
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TL;DR: According to the results of an experiment on hydrogen production using the reduced iron nanoparticles, the reaction efficiency of the hydrogen generation at a temperature of 673 K was more than 94% for the ideal amount of generated hydrogen.
Abstract: A recyclable energy cycle using a pulsed laser and base-metal nanoparticles is proposed In this energy cycle, iron nanoparticles reduced from iron oxides by laser ablation in liquid are used for hydrogen generation The laser energy can be stored in the base-metal nanoparticles as the difference between the chemical energies of iron oxide and iron According to the results of an experiment on hydrogen production using the reduced iron nanoparticles, the reaction efficiency of the hydrogen generation at a temperature of 673 K was more than 94% for the ideal amount of generated hydrogen
21 citations
TL;DR: In this paper, the authors constructed a theory to explain the mechanism of laser generation with a high optical-optical conversion efficiency for Nd3+- and Cr3+doped yttrium aluminum ceramics when sunlight or lamplight sources are used for pumping.
Abstract: We constructed a theory to explain the mechanism of laser generation with a high optical–optical conversion efficiency for Nd3+- and Cr3+-doped yttrium aluminum ceramics when sunlight or lamplight sources are used for pumping. As a result, a unique mechanism of laser action was found where the solar or lamp-light power could be converted to laser power with a high efficiency close to 80%, which has not previously been observed. The high conversion efficiency was not only considered to be based on one-to-one photon conversion but on two-photon excitation by a single photon with phonon assistance. Thus, the mechanism of lasing action should include a process where thermal energy is converted to photon energy. The theoretical results we obtained were consistent with those of the experiments.
19 citations
"Electrical Property of Laser-Sinter..." refers background or methods in this paper
...Metal oxides have already been reduced a t low cost by using a pulsed laser with a high peak power in liquids [7-15]....
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...The Nd/Cr:YAG ceramic is employed in solar-pumped laser [14]....
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...We previously proposed an energy cycle using solar-pumped pulse lasers and metals [12-15]....
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Journal Article•
TL;DR: In this article, the authors proposed an energy cycle that uses solar-pumpe d pulse and base me tal nanoparticles for laser ablation in liquid for the energy cycle.
Abstract: Research on the produce of re ne wable e ne rgy as a source of solar powe r has continuously ad vance d We have propose d an en ergy cycle that uses solar- pumpe d pulse lase rs and base me tal nanoparticles He re , Fe and Al nanoparticles we re pre pare d by lase r ablation in liquid for the e nergy cycle Solar powe r was confine d in base me tal nanoparticles Me ta l plates we re fabricate d by sinte ring metal paste with base me tal nanoparticles Electricity was ge ne rate d by air ce lls using the sintere d me tal plate A highly re pe titive laser pulse , which was an alte rnative to lasers drive n by solar power, was use d for laser ablation in liquid, and me tal oxides (Fe 3O4 or Al2O3) we re re duce d and metal nanoparticles were fabricate d Me tal plates with a low e lectrical resistance were fabricate d by sinte ring them at a low tempe rature of 520 K The e lectrical properties of the air ce lls fabricate d using sinte re d paste with nanoparticles as negative e lectrical cathodes we re the same as those of the air ce lls fabricate d in a blast furnace It was found that the sinte re d me tal nanopaste could be use d for air ce lls
11 citations