Journal articles: 'Pulsed-laser Induced Chemical Synthesis'

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Avilova, Ekaterina A., Evgeniia M. Khairullina, Andrey Yu Shishov, Elizaveta A. Eltysheva, Vladimir Mikhailovskii, Dmitry A. Sinev, and Ilya I. Tumkin. "Direct Laser Writing of Copper Micropatterns from Deep Eutectic Solvents Using Pulsed near-IR Radiation." Nanomaterials 12, no. 7 (March 29, 2022): 1127. http://dx.doi.org/10.3390/nano12071127.

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In this study, we developed a method for the fabrication of electrically conductive copper patterns of arbitrary topology and films on dielectric substrates, by improved laser-induced synthesis from deep eutectic solvents. A significant increase in the processing efficiency was achieved by acceptor substrate pretreatment, with the laser-induced microplasma technique, using auxiliary glass substrates and optional laser post-processing of the recorded structures; thus, the proposed approach offers a complete manufacturing cycle, utilizing a single, commercially available, pulsed Yb fiber laser system. The potential implications of the presented research are amplified by the observation of laser-induced periodic surface structures (LIPSSs) that may be useful for the further tuning of tracks’ functional properties.

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Švrček, Vladimir. "Nanocrystalline silicon and carbon nanotube nanocomposites prepared by pulsed laser fragmentation." Pure and Applied Chemistry 80, no. 11 (January 1, 2008): 2513–20. http://dx.doi.org/10.1351/pac200880112513.

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This paper outlines the synthesis of nanocrystalline silicon (nc-Si) by nanosecond pulsed laser fragmentation of Si micrograins in liquid solutions, and characterization of the products. We compare micrograin fragmentations in deionized water, and in undoped and phosphorus-doped ethylpolysilicate (C2H5O[SiO(C2H5O)2]n C2H5) based polymers. We show that dissolution and subsequent laser fragmentation of micrograins is more efficient in both polymeric media than in water. In the case of water, micrograin surface wetting by ethanol prior to introduction into water is essential to achieve fragmentation. Prepared nc-Si/polymer nanocomposites display visible photoluminescence (PL) (~430 nm) at room temperature. The phosphorus polymer induces a blue shift of the PL peak. In addition, induced shock waves generated at sufficiently high laser irradiation intensities (>4.3 mJ/pulse) cause carbon nanotube (CNT) cavities to be filled by freshly prepared luminescent nc-Si/polymer nanocomposite.

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Polman, A., W. C. Sinke, M. J. Uttormark, and Michael O. Thompson. "Pulsed-laser induced transient phase transformations at the Si–H2O interface." Journal of Materials Research 4, no. 4 (August 1989): 843–56. http://dx.doi.org/10.1557/jmr.1989.0843.

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Phase transformations at the Si–H2O interface, induced by nanosecond pulsed laser irradiation, were studied in real time. Si samples were irradiated using a 4 ns pulse from a Q-switched frequency-doubled Nd:YAG laser while immersed in the transparent liquid. Using time-resolved conductivity and reflectivity techniques, in combination with modeling of optical parameters and heat flow, transient processes in the Si, the H2O, and at the interface have been unraveled. In the liquid, local rapid heating occurs as a result of heat flow across the interface, and formation of a low-density steam phase occurs on a nanosecond timescale. Expansion of this phase is followed by a collapse after 200 ns. These rapid phase transformations in the water initiate a shock wave with a pressure of 0.4± 0.3 kbar. Transient phase transformations and the heat flow into the water during the laser pulse influence the energy coupling into the sample, resulting in an effective laser pulse shortening. The pulse shortening and the additional heat flow into the water during solidification result in a 30% enhancement of the solidification velocity for 270 nm deep melts. Cross-section transmission electron microscopy data reveal that the Si surface is planar after irradiation and is inert to chemical reactions during irradiation. Recent experiments described in the literature concerning pulsed-laser induced synthesis at the solid-liquid interface are reviewed and discussed in the context of the fundamental phenomena presently observed.

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Ghaisas, Smita, R. D. Vispute, S. B. Ogale, S. M. Choudhari, S. M. Kanetkar, S. K. Kulkarni, S. Mahamuni, S. Badrinarayan, and S. V. Ghaisas. "The study of pulsed laser deposited films from a pressed, sintered, W–C mixture at two different fluences." Journal of Materials Research 7, no. 12 (December 1992): 3250–54. http://dx.doi.org/10.1557/jmr.1992.3250.

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The reactive aspect of pulsed laser induced vaporization has been explored via synthesis of tungsten carbide films from an unreacted sintered mixture of the W–C system. Using low-angle x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS), it is shown that stoichiometry and the extent of chemical compound formation in the deposited films depend upon the laser fluence. Two cases with energy density 20 J/cm2 and 40 J/cm2 are discussed and compared. An attempt has been made to illustrate the mechanism behind the reactive aspect of the deposition.

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KUMAR, DHIRAJ, SUNIL KUMAR, and H. S. BHATTI. "LASER-INDUCED PHOTOLUMINESCENT STUDIES OF Al-DOPED ZINC OXIDE NANOPARTICLES." International Journal of Nanoscience 09, no. 05 (October 2010): 439–45. http://dx.doi.org/10.1142/s0219581x10007101.

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In this paper, addition of aluminum in zinc oxide is incorporated using low-temperature chemical synthesis route. Aluminum ions help in crystallization of zinc oxide nanoparticles. Characterization of the synthesized nanoparticles of zinc oxide has been done using Transmission electron microscope (TEM), and X-ray diffraction (XRD) analysis, Energy-resolved photoluminescence (PL) spectra and Time-resolved laser-induced photoluminescence (TRPL) at room temperature. Transmission electron microscopic observations and X-Ray diffraction studies indicate highly crystalline nature and particle size of the order of 20 nm in ZnO:Al . Time-resolved laser-induced photoluminescence measurements have been done using pulsed nitrogen laser as an excitation source, operated at wavelength 337.1 nm and having high peak output power of 1 MW. The results show that at higher concentrations of Al doping in host ZnO phosphor, emission intensity is more by several orders of magnitude and lifetime shortening indicates that these nanoparticles are more efficient as compared with lower concentrations of dopant.

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Flimelova, Miroslava, and Yury V. Ryabchikov. "A Facile Route of Manufacturing of Silicon-Based Nanostructures with Tuned Plasmonic Properties." Journal of Physics: Conference Series 2015, no. 1 (November 1, 2021): 012128. http://dx.doi.org/10.1088/1742-6596/2015/1/012128.

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Abstract An environment-friendly method of pulsed laser ablation in liquids is successfully employed for structural modification of silicon nanoparticles leading to a considerable narrowing of their size distribution accompanied with a reduction of the mean size. Contamination-free conditions of synthesis ensure the chemical purity of formed nanostructures that may reduce toxicity issues. Such a laser-induced modification leads to the appearance of plasmonic properties in semiconductor-based nanomaterials. Their spectral position can easily be varied in the whole visible range. Combined in one nanoparticle properties of semiconductors and noble metals can strongly promote applications of composite laser-synthesized nanoparticles for biosensing (using their plasmonic-based surface-enhanced ability) and bioimaging (using their both optical and magnetic abilities) purposes.

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Rajan, Magesh T., Rizbi Hassan, and Haiping Hong. "Laser Plasma Induced Cu2O Nanoparticle Synthesis in Ethanol and Nanofluid Particle Characterization." Journal of Nanofluids 8, no. 8 (December 1, 2019): 1676–82. http://dx.doi.org/10.1166/jon.2019.1718.

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Nanofluids with nanoscale colloidal suspensions having condensed nanomaterials have been found to show highly-enhanced physical, chemical, thermal and transport properties and signifies great potential in many fields. In this article, laser induced plasmas at liquid-metal phase boundaries is investigated for copper oxide (Cu2O) nanoparticle synthesis in ethanol without any surfactants. The nanoparticles are generated using 1064 nm NdYAG laser ablation in a water confined plasma with 1.5 J laser energy pulsed at 10 Hz for 4 minutes, which resulted in narrow size distribution of nanoparticles of size ranging from 2 to 12 nm dispersed in ethanol sans surfactant. The synthesized Cu2O nanoparticles in ethanol are characterized for their sizes, surface morphology, crystalline structures and elemental compositions etc. The dynamic light scattering (DLS) measurements show Cu2O nanoparticles synthesized have an average size of 4.5 nm. The scanning electron microscope (SEM) measurements show Cu2O nanoparticles exhibit isolated and agglomerated nanoparticles with near-spherical and irregular surface morphologies. Transmission electron microscopy (TEM) measurements show Cu2O nanoparticles with near-spherical and irregular shapes, and the average size of the nanoparticles is ˜4.5 nm. Selected area electron diffraction (SAED) measurements show poly crystalline structure present in the Cu2O nanoparticles. The energy-dispersive X-ray spectroscopy (EDX) measurements show the purity of Cu2O nanoparticles with identification of significant Cu and O elements. X-ray diffraction (XRD) measurements confirm that the Cu2O nanoparticles are polycrystalline in nature and confirmed the presence of single phase of Cu2O nanoparticles.

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Furusato, Tomohiro, Mitsuru Sasaki, Yoshinobu Matsuda, and Takahiko Yamashita. "Underwater shock wave induced by pulsed discharge on water." Journal of Physics D: Applied Physics 55, no. 11 (December 13, 2021): 115203. http://dx.doi.org/10.1088/1361-6463/ac3f57.

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Abstract Plasmas on liquids have provided significant applications in material, environmental, and biological sciences. The mechanisms of these chemical reactions in liquids have been primarily described by the plasma–liquid interactions and convection by an electrohydrodynamic flow. Although shock waves play a significant role in radical formation, agitation and cell destruction, not much information is available on underwater shock waves induced by the surface discharge on water. In this study, an underwater shock wave generated by the pulsed surface discharge on water using the laser shadowgraph method has been demonstrated. The results reveal that the shock wave generated by the discharge on water was transmitted into the water. The mean velocity of the shock wave reached 1.7 km s−1. The results indicate that the surface discharge accelerates the reaction in the water by the combined action of the underwater shock wave and the plasma reaction at the air–water interface. The results are expected to aid in the understanding the mechanisms of existing applications, such as decomposition, synthesis, and sterilization.

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A. Thuhaib, Omar, and Hassan Hashim. "Characterization and Synthesis of CdO and CDO1-x:Sx Films by Pulsed Laser Deposition." Al-Nahrain Journal of Science 24, no. 4 (December 1, 2021): 26–31. http://dx.doi.org/10.22401/anjs.24.4.04.

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In this work, we analyze the effects of S doping on the structural and optical characteristics of pure cadmium oxide (CdO) filmsat varying concentrations of CdO1−x:Sx(X=0.2, 0.4, and 0.6), Sulfur is a chemical element with the atomic number 16 and the symbol S. The films were created using a laser-induced plasma (LIP) with a wavelength of 1064 nm and a duration of 9 ns at a pressure of 2.5×10−2mbar.X-ray diffraction studies revealed that all of the produced films are polycrystalline. The topography of the film's surface was evaluated using AFM, and the findings revealed that as the amount of doping increases, so does the grain size, along with an increase in the average roughness. The absorbance spectrum of the wavelength range (350-1100) nm was used to investigate the optical characteristics of all films. This rise might be the so-called Borsstein-Moss displacement has been viewed as a result of this. because the lowest layers of the conduction beams are densely packed with Because electrons require more energy to move, it seems as though the energy disparity widens.

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Mollah, S., S. J. Henley, C. E. Giusca, and S. R. P. Silva. "Photo-Chemical Synthesis of Iron Oxide Nanowires Induced by Pulsed Laser Ablation of Iron Powder in Liquid Media." Integrated Ferroelectrics 119, no. 1 (November 12, 2010): 45–54. http://dx.doi.org/10.1080/10584587.2010.503790.

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Nancy, Parvathy, Jiya Jose, Nithin Joy, Sivakumaran Valluvadasan, Reji Philip, Rodolphe Antoine, Sabu Thomas, and Nandakumar Kalarikkal. "Fabrication of Silver-Decorated Graphene Oxide Nanohybrids via Pulsed Laser Ablation with Excellent Antimicrobial and Optical Limiting Performance." Nanomaterials 11, no. 4 (March 30, 2021): 880. http://dx.doi.org/10.3390/nano11040880.

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The demand for metallic nanoparticle ornamented nanohybrid materials of graphene oxide (GO) finds copious recognition by virtue of its advanced high-tech applications. Far apart from the long-established synthesis protocols, a novel laser-induced generation of silver nanoparticles (Ag NPs) that are anchored onto the GO layers by a single-step green method named pulsed laser ablation has been exemplified in this work. The second and third harmonic wavelengths (532 nm and 355 nm) of an Nd:YAG pulsed laser is used for the production of Ag NPs from a bulk solid silver target ablated in an aqueous solution of GO to fabricate colloidal Ag-GO nanohybrid materials. UV-Vis absorption spectroscopy, Raman spectroscopy, and TEM validate the optical, structural, and morphological features of the hybrid nanomaterials. The results revealed that the laser-assisted in-situ deposition of Ag NPs on the few-layered GO surface improved its antibacterial properties, in which the hybrid nanostructure synthesized at a longer wavelength exhibited higher antibacterial action resistance to Escherichia coli (E. coli) than Staphylococcus aureus (S. aureus) bacteria. Moreover, nonlinear optical absorption (NLA) of Ag-GO nanohybrid was measured using the open aperture Z-scan technique. The Z-scan results signify the NLA properties of the Ag-GO hybrid material and have a large decline in transmittance of more than 60%, which can be employed as a promising optical limiting (OL) material.

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Rybaltovsky, Alexey, Evgeniy Epifanov, Dmitriy Khmelenin, Andrey Shubny, Yuriy Zavorotny, Vladimir Yusupov, and Nikita Minaev. "Two Approaches to the Laser-Induced Formation of Au/Ag Bimetallic Nanoparticles in Supercritical Carbon Dioxide." Nanomaterials 11, no. 6 (June 11, 2021): 1553. http://dx.doi.org/10.3390/nano11061553.

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Two approaches are proposed for the synthesis of bimetallic Au/Ag nanoparticles, using the pulsed laser ablation of a target consisting of gold and silver plates in a medium of supercritical carbon dioxide. The differences between the two approaches related to the field of “green chemistry” are in the use of different geometric configurations and different laser sources when carrying out the experiments. In the first configuration, the Ag and Au targets are placed side-by-side vertically on the side wall of a high-pressure reactor and the ablation of the target plates occurs alternately with a stationary “wide” horizontal beam with a laser pulse repetition rate of 50 Hz. In the second configuration, the targets are placed horizontally at the bottom of a reactor and the ablation of their parts is carried out by scanning from above with a vertical “narrow” laser beam with a pulse repetition rate of 60 kHz. The possibility of obtaining Ag/Au alloy nanoparticles is demonstrated using the first configuration, while the possibility of obtaining “core–shell” bimetallic Au/Ag nanoparticles with a gold core and a silver shell is demonstrated using the second configuration. A simple model is proposed to explain the obtained results.

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Kitahama, Katsuki, Kazuhiko Hirata, Hirohide Nakamatsu, Shichio Kawai, Naoji Fujimori, Takahiro Imai, Hiroshi Yoshino, and Akira Doi. "Synthesis of diamond by laser‐induced chemical vapor deposition." Applied Physics Letters 49, no. 11 (September 15, 1986): 634–35. http://dx.doi.org/10.1063/1.97063.

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Popov, Anton A., Gleb V. Tikhonowski, Pavel V. Shakhov, Elena A. Popova-Kuznetsova, Gleb I. Tselikov, Roman I. Romanov, Andrey M. Markeev, Sergey M. Klimentov, and Andrei V. Kabashin. "Synthesis of Titanium Nitride Nanoparticles by Pulsed Laser Ablation in Different Aqueous and Organic Solutions." Nanomaterials 12, no. 10 (May 13, 2022): 1672. http://dx.doi.org/10.3390/nano12101672.

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Owing to a strong photothermal response in the near-IR spectral range and very low toxicity, titanium nitride (TiN) nanoparticles (NPs) synthesized by pulsed laser ablation in liquids (PLAL) present a novel appealing object for photo-induced therapy of cancer, but the properties of these NPs still require detailed investigation. Here, we have elaborated methods of femtosecond laser ablation from the TiN target in a variety of liquid solutions, including acetonitrile, dimethylformamide, acetone, water, and H2O2, to synthesize TiN NPs and clarify the effect of liquid type on the composition and properties of the formed NPs. The ablation in all solvents led to the formation of spherical NPs with a mean size depending on the liquid type, while the composition of the NPs ranged from partly oxidized TiN to almost pure TiO2, which conditioned variations of plasmonic peak in the region of relative tissue transparency (670–700 nm). The degree of NP oxidation depended on the solvent, with much stronger oxidation for NPs prepared in aqueous solutions (especially in H2O2), while the ablation in organic solvents resulted in a partial formation of titanium carbides as by-products. The obtained results contribute to better understanding of the processes in reactive PLAL and can be used to design TiN NPs with desired properties for biomedical applications.

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Kizaki, Yoshimi, Toshio Kandori, and Yoshiyasu Fujitani. "Synthesis and Characterization of Si3N4Powder Produced by Laser-Induced Chemical Reaction." Japanese Journal of Applied Physics 24, Part 1, No. 7 (July 20, 1985): 800–805. http://dx.doi.org/10.1143/jjap.24.800.

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Fauteux, Christian, Riadh Smirani, Joseph Pegna, My Ali El Khakani, and Daniel Therriault. "Fast synthesis of ZnO nanostructures by laser-induced chemical liquid deposition." Applied Surface Science 255, no. 10 (March 2009): 5359–62. http://dx.doi.org/10.1016/j.apsusc.2008.09.094.

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Liu, Zhikun, Zeyuan Cao, Biwei Deng, Yuefeng Wang, Jiayi Shao, Prashant Kumar, C. Richard Liu, Bingqing Wei, and Gary J. Cheng. "Ultrafast and scalable laser liquid synthesis of tin oxide nanotubes and its application in lithium ion batteries." Nanoscale 6, no. 11 (2014): 5853–58. http://dx.doi.org/10.1039/c3nr06444a.

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Alabdulkarim, Mohamad E., Wendy D. Maxwell, Vibhor Thapliyal, and James L. Maxwell. "A Comprehensive Review of High-Pressure Laser-Induced Materials Processing, Part I: Laser-Heated Diamond Anvil Cells." Journal of Manufacturing and Materials Processing 6, no. 5 (September 29, 2022): 111. http://dx.doi.org/10.3390/jmmp6050111.

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Laser-heated diamond anvil cell (LH-DAC) experimentation has emerged as a leading technique for materials processing at extreme pressures and temperatures. LH-DAC systems are often employed to better characterise the structure and properties of materials in applications ranging from condensed matter physics to geophysical research to planetary science. This article reviews LH-DAC and related laser-based characterisation, as the first part of a series within the broader context of all high-pressure laser-induced material processing. In part I of this review, a synopsis of laser-heated diamond anvil cell experimental methods, developmental history, fundamental physicochemical processes, and emerging research trends are provided. Important examples of minerals/materials modified during LH-DAC investigations (since their inception) are also tabulated, including key phase transformations, material syntheses, laser parameters, and process conditions—as a reference for the reader and as a guide for directing future research efforts. Note that laser-dynamic-compression within diamond anvil cells (LDC-DAC experimentation) and laser-induced reactive chemical synthesis within diamond anvil cells (LRS-DAC experimentation) are treated separately, as Parts II and III of this review.

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Glumac, N. G., Y.-J. Chen, and G. Skandan. "Diagnostics and Modeling of Nanopowder Synthesis in Low Pressure Flames." Journal of Materials Research 13, no. 9 (September 1998): 2572–79. http://dx.doi.org/10.1557/jmr.1998.0359.

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Laser-induced fluorescence, thermophoretic sampling, laser light scattering, and emission spectroscopy have been used to probe low pressure hydrogen/oxygen flames in which 3–50 nm, loosely agglomerated oxide nanopowders have been synthesized at high production rates by the pyrolysis of precursor vapors, followed by condensation in the gas phase. These measurements have enabled the identification of pyrolysis, condensations, and particle growth regions in the flame. Flame simulations using a one-dimensional stagnation flow model, with complex chemistry, demonstrate that the chemical and thermal flame structure can be accurately predicted for flames without a precursor. Furthermore, some flame structure changes induced by the addition of a precursor can be simulated by addition of analogous species to the chemical mechanism.

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Endoh, Shigehisa, and Kazuo Takeuchi. "Fine silicon powder synthesis by the laser induced reaction." Advanced Powder Technology 3, no. 3 (1992): 219–26. http://dx.doi.org/10.1016/s0921-8831(08)60671-8.

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Um, Seung‐Hoon, Yong‐Woo Chung, Youngmin Seo, Hyunseon Seo, Myoung‐Ryul Ok, Yu‐Chan Kim, Hyung‐Seop Han, Justin J. Chung, James R. Edwards, and Hojeong Jeon. "Robust Hydroxyapatite Coating by Laser‐Induced Hydrothermal Synthesis." Advanced Functional Materials 30, no. 48 (September 15, 2020): 2005233. http://dx.doi.org/10.1002/adfm.202005233.

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Lee, Yeong A., Kyuyeon Jang, and Hana Yoon. "A Facile and Scalable Fabrication of High-Performance Flexible Laser-Induced-Graphene Micro-Supercapacitors Using Ultrafast Pulse Laser." ECS Meeting Abstracts MA2022-02, no. 7 (October 9, 2022): 2562. http://dx.doi.org/10.1149/ma2022-0272562mtgabs.

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The rapid growth of wearable and portable electronics has promoted the development of microscale energy storage devices. Among these devices, microsupercapacitors (MSCs) have emerged as promising flexible energy storage devices owing to their high power density, high charge/discharge rate, and long-term cycling stability.[1,2,3] Most synthesis method of graphene electrodes for flexible MSCs rely on complex processes or chemical synthesis routes, such as photolithography, mechanical exfoliation, or chemical and thermal reduction. On the other hand, laser direct writing are a simple, design-flexible, highly scalable, and cost-effective method for graphene production. Here, we developed two types of green flexible microsupercapacitor using femtosecond pulse laser. First, we report a high performance sticker-type flexible microsupercapacitor using highly swollen reduced-graphene oxide electrodes fabricated by an ultrashort pulse laser.[4] Second, we demonstrate the direct fabrication of highly conductive, intrinsically flexible, and green microelectrodes from naturally fallen leaves in ambient air using femtosecond laser pulses without any additional materials.[5] Both types of MSCs not only showed excellent electrochemical performance, but were confirmed to work as a power supply for various applications such as LED and thermometer. Therefore, our flexible microsupercapacitors can be widely applied as energy-storage devices for flexible/wearable electronics.

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Zhang, Aodong, Jian Xu, Yucen Li, Ming Hu, Zijie Lin, Yunpeng Song, Jia Qi, Wei Chen, Zhaoxiang Liu, and Ya Cheng. "Three-Dimensional Large-Scale Fused Silica Microfluidic Chips Enabled by Hybrid Laser Microfabrication for Continuous-Flow UV Photochemical Synthesis." Micromachines 13, no. 4 (March 30, 2022): 543. http://dx.doi.org/10.3390/mi13040543.

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We demonstrate a hybrid laser microfabrication approach, which combines the technical merits of ultrafast laser-assisted chemical etching and carbon dioxide laser-induced in situ melting for centimeter-scale and bonding-free fabrication of 3D complex hollow microstructures in fused silica glass. With the developed approach, large-scale fused silica microfluidic chips with integrated 3D cascaded micromixing units can be reliably manufactured. High-performance on-chip mixing and continuous-flow photochemical synthesis under UV irradiation at ~280 nm were demonstrated using the manufactured chip, indicating a powerful capability for versatile fabrication of highly transparent all-glass microfluidic reactors for on-chip photochemical synthesis.

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Oshima, Yoshito, Hiroshi Kawamoto, Kayoko Iguchi, and Seiichiro Koda. "A novel laser-induced synthesis of 1,1-dichloroethylene from 1,1-dichloroethane." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 26, no. 3 (1993): 280–85. http://dx.doi.org/10.1252/jcej.26.280.

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Auciello, O., A. I. Kingon, and S. B. Krupanidhi. "Sputter Synthesis of Ferroelectric Films and Heterostructures." MRS Bulletin 21, no. 6 (June 1996): 25–30. http://dx.doi.org/10.1557/s0883769400046042.

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Ferroelectric films can display a wide range of dielectric, ferroelectric, piezoelectric, electrostrictive, and pyroelectric properties. The potential utilization of these properties in a new generation of devices has driven the intensive studies on the synthesis, characterization, and determination of processing-microstructure-property relationships of ferroelectric thin films during the last five years. In addition there has been an increased drive for integrating ferroelectric film-based heterostructures with different substrate materials to demonstrate numerous devices that exploit the dielectric, ferroelectric, piezoelectric, electrostrictive, and pyroelectric properties of these materials. For example the high dielectric permittivities of perovskite-type materials can be advantageously used in dynamic random-access memories (DRAMs), while the large values of switchable remanent polarization of ferroelectric materials are suitable for nonvolatile ferroelectric random-access memories (NVFRAMs).Various vapor-phase deposition techniques such as plasma and ion-beam sputter deposition (PSD and IBSD, respectively), pulsed laser-ablation deposition (PLAD), electron-beam or oven-induced evaporation for molecular-beam epitaxy (MBE), and chemical vapor deposition (CVD) have been applied to produce ferroelectric films and layered heterostructures. See References 4–7 for recent reviews. However, work is still necessary to optimize the techniques to produce device-quality films on large semiconductor substrates in a way that is fully compatible with existing semiconductor process technology. Therefore research efforts should be focused on the optimization of suitable process methods and on the investigation of processing-composition-microstructure property relationships. These efforts are the focus of this article with emphasis on PSD and IBSD techniques.

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Fantoni, R., E. Borsella, S. Piccirillo, R. Ceccato, and S. Enzo. "Laser synthesis and crystallographic characterization of ultrafine SiC powders." Journal of Materials Research 5, no. 1 (January 1990): 143–50. http://dx.doi.org/10.1557/jmr.1990.0143.

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High purity, ultrafine SiC powders have been produced from gas phase reactants (SiH4, C2H2) in a CO2 laser induced process. The flow reactor designed to operate with a medium power (10–50 W) continuous wave CO2 laser source is described. The mechanism of gas phase reactions involved has been investigated by means of on-line optical diagnostics. Powders produced have been characterized by means of conventional chemical and spectroscopic methods. The x-ray results point out a growth mechanism by coalescence; i.e., whole islands move in the flame to take part in binary collisions, analogously to that observed for particles produced by inert gas evaporation.

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Pan, Zhengwei, Hualun Li, and Litong Zhang. "Laser synthesis and crystallization of nanocomposite Si/C/N powder." Journal of Materials Research 13, no. 7 (July 1998): 1996–2002. http://dx.doi.org/10.1557/jmr.1998.0280.

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Ultrafine preceramic Si/C/N composite powders have been prepared from hexamethyldisilazane (HMDS) by laser-induced gas phase reaction, using a new kind of tworeaction-zone reactor which could efficiently increase laser efficiency and production yield compared with a one-reaction-zone reactor. The as-formed products were nanosized (50–80 nm), amorphous powders containing Si–C and Si–N bonds homogeneously mixed with some excess carbon. The production yield was in the range of 88–120 g/h. Changes of chemical composition and crystallization of the powders during heat treatment at 1350 and 1550 °C under nitrogen for 1 h were studied.

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Kornowski, Andreas, Michael Giersig, Ralf Vogel, Abdelkarim Chemseddine, and Horst Weller. "Nanometer-sized colloidal germanium particles: Wet-chemical synthesis, laser-induced crystallization and particle growth." Advanced Materials 5, no. 9 (September 1993): 634–36. http://dx.doi.org/10.1002/adma.19930050907.

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Musci, M., M. Notaro, F. Curcio, C. Casale, and G. De Michele. "Laser synthesis of vanadium-titanium oxide catalysts." Journal of Materials Research 7, no. 10 (October 1992): 2846–52. http://dx.doi.org/10.1557/jmr.1992.2846.

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A laser-induced process has been studied and developed for the synthesis either of pure TiO2 powders for use as a catalyst support or of mixed Ti1−xVxO2 oxides to be used directly as catalysts in the selective catalytic reduction of nitrogen oxides with ammonia. The radiation source is a 600 W cw CO2 laser and the precursors are titanium and vanadium alkoxides whose vapors are carried under the laser beam by controlled flows of an inert gas and of a reaction sensitizer. The study of the process has been mainly devoted to the optimization of the production rate and of the reaction efficiency. The powder characteristics, related to the process parameters, have been investigated through different techniques. The results show that the particles are monodispersed, unaggregated, monocrystalline with anatase structure and their diameters can be as small as 50 A. Vanadium contents up to X = 0.25 have been obtained in Ti1−xVxO2 compounds, without V2O5 segregation. Finally, a comparison between the behavior of surface VOx active sites has been carried out in catalysts prepared by chemical impregnation of TiO2 and in the mixed Ti–V oxide powders.

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Crunteanu, A., M. Charbonnier, M. Romand, F. Vasiliu, D. Pantelica, F. Negoita, and R. Alexandrescu. "Synthesis and characterization of carbon nitride thin films obtained by laser induced chemical vapour deposition." Surface and Coatings Technology 125, no. 1-3 (March 2000): 301–7. http://dx.doi.org/10.1016/s0257-8972(99)00577-0.

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Park, Jaeho, Kyungwoo Lee, Jaehong Lee, Hae Won Hwang, Goeen Jeong, Kyung Yeun Kim, Yu-Chan Kim, et al. "Improvement of Yttrium Oxyfluoride Coating with Modified Precursor Solution for Laser-Induced Hydrothermal Synthesis." Coatings 12, no. 6 (May 27, 2022): 740. http://dx.doi.org/10.3390/coatings12060740.

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In the semiconductor manufacturing process, the inner walls of the equipment are coated with yttrium-based oxides for etch resistance against plasma exposure. Yttrium oxyfluoride (YOF) particle synthesis and coating methods have been actively studied owing to their high erosion resistance compared to Y2O3 and Al2O3. Owing to the formation of a rough and porous coating layer by thermal spray-coating, the coating layer disintegrates, as the etching process has been conducted for a long time. Laser-induced synthesis and coating technology offer several advantages, including simplified process steps, ease of handling, and formation of a dense coating layer on the target material. In this study, YOF was coated on an aluminum substrate using a modified precursor solution. The NaF and HMTA were added to the precursor solution, resulting in enhanced synthetic reactivity and stabilizing the oxides. The material coated on the surface was analyzed based on the characteristics of composition, chemical bonding, and phase identification. We found that the coating properties can be improved by using an appropriate combination of modified precursor solutions and laser parameters. Therefore, the findings in this study are expected to be utilized in the field of coating technology.

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Dong, Xuan Xuan, Lei Zhang, and Jian Fu. "Laser-Induced Thermal Bubble-Mixing on a Microfluidic Platform for Lab-on-a-Chip Applications." Advanced Materials Research 557-559 (July 2012): 2197–201. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.2197.

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This paper discusses the study of the multimode evolution of microfiber taper and its potential application of micromixer in the lab-on-a-chip. By using numerical simulation, multimode interference effects are demonstrated in the taper transition of a micro-nano fiber. Due to the leaked optical energy gasifies the solution surrounding the taper and produces air bubbles, the laminar flow effect is destroyed with the help of disturbance of air bubble and two solutions are mixed quickly. Therefore, it will be used in microfluidic platform for chemical analysis & testing, chemical synthesis and environmental monitoring.

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33

Bucharskaya, Alla B., Nikolai G. Khlebtsov, Boris N. Khlebtsov, Galina N. Maslyakova, Nikita A. Navolokin, Vadim D. Genin, Elina A. Genina, and Valery V. Tuchin. "Photothermal and Photodynamic Therapy of Tumors with Plasmonic Nanoparticles: Challenges and Prospects." Materials 15, no. 4 (February 21, 2022): 1606. http://dx.doi.org/10.3390/ma15041606.

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Cancer remains one of the leading causes of death in the world. For a number of neoplasms, the efficiency of conventional chemo- and radiation therapies is insufficient because of drug resistance and marked toxicity. Plasmonic photothermal therapy (PPT) using local hyperthermia induced by gold nanoparticles (AuNPs) has recently been extensively explored in tumor treatment. However, despite attractive promises, the current PPT status is limited by laboratory experiments, academic papers, and only a few preclinical studies. Unfortunately, most nanoformulations still share a similar fate: great laboratory promises and fair preclinical trials. This review discusses the current challenges and prospects of plasmonic nanomedicine based on PPT and photodynamic therapy (PDT). We start with consideration of the fundamental principles underlying plasmonic properties of AuNPs to tune their plasmon resonance for the desired NIR-I, NIR-2, and SWIR optical windows. The basic principles for simulation of optical cross-sections and plasmonic heating under CW and pulsed irradiation are discussed. Then, we consider the state-of-the-art methods for wet chemical synthesis of the most popular PPPT AuNPs such as silica/gold nanoshells, Au nanostars, nanorods, and nanocages. The photothermal efficiencies of these nanoparticles are compared, and their applications to current nanomedicine are shortly discussed. In a separate section, we discuss the fabrication of gold and other nanoparticles by the pulsed laser ablation in liquid method. The second part of the review is devoted to our recent experimental results on laser-activated interaction of AuNPs with tumor and healthy tissues and current achievements of other research groups in this application area. The unresolved issues of PPT are the significant accumulation of AuNPs in the organs of the mononuclear phagocyte system, causing potential toxic effects of nanoparticles, and the possibility of tumor recurrence due to the presence of survived tumor cells. The prospective ways of solving these problems are discussed, including developing combined antitumor therapy based on combined PPT and PDT. In the conclusion section, we summarize the most urgent needs of current PPT-based nanomedicine.

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Syubaev, Sergey, Stanislav Gurbatov, Evgeny Modin, Denver P. Linklater, Saulius Juodkazis, Evgeny L. Gurevich, and Aleksandr Kuchmizhak. "Laser Printing of Plasmonic Nanosponges." Nanomaterials 10, no. 12 (December 4, 2020): 2427. http://dx.doi.org/10.3390/nano10122427.

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Three-dimensional porous nanostructures made of noble metals represent novel class of nanomaterials promising for nonlinear nanooptics and sensors. Such nanostructures are typically fabricated using either reproducible yet time-consuming and costly multi-step lithography protocols or less reproducible chemical synthesis that involve liquid processing with toxic compounds. Here, we combined scalable nanosecond-laser ablation with advanced engineering of the chemical composition of thin substrate-supported Au films to produce nanobumps containing multiple nanopores inside. Most of the nanopores hidden beneath the nanobump surface can be further uncapped using gentle etching of the nanobumps by an Ar-ion beam to form functional 3D plasmonic nanosponges. The nanopores 10–150 nm in diameter were found to appear via laser-induced explosive evaporation/boiling and coalescence of the randomly arranged nucleation sites formed by nitrogen-rich areas of the Au films. Density of the nanopores can be controlled by the amount of the nitrogen in the Au films regulated in the process of their magnetron sputtering assisted with nitrogen-containing discharge gas.

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35

Ye, Ruquan, and Libei Huang. "Direct laser-assisted manufacturing and patterning of graphene from polymers." Special Issue with Awarded and Shortlisted Papers from the HKIE Outstanding Paper Award for Young Engineers/Researchers 2019 26, no. 4 (December 20, 2019): 166–74. http://dx.doi.org/10.33430/v26n4thie-2019-0018.

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Graphene is a two-dimensional material possessing unique electrical, optical and thermal properties. Broad applications based on its pristine form or hybrids have been developed and applied in various fields, including chemistry, biology, electrical engineering, aerospace and environmental management. To meet the market demand, great efforts have been taken to develop a cost-effective method for the synthesis and fabrication of graphene materials and electronics. Among all the reported methods, conventional physical and chemical methods such as liquid/ gas phase-based or mechanical exfoliation, chemical vapour deposition (CVD) and reduction of graphene oxide, were widely adopted in the early stage. In this study, the use of a CO2 infrared laser for direct manufacturing and patterning of graphene, namely laser-induced graphene (LIG) is introduced. It starts with the principle of the laser-induced transformation, including the influence of laser parameters on the morphology and property of graphene. Then the formation of composites and methods for continuous manufacturing will be discussed. A few representative applications of LIG will be showcased to demonstrate its versatility. These include the applications of single LIG devices and their integration into full devices. Finally, the limitation of LIG technique and future engineering practice will be highlighted.

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Kostopoulou, Athanasia, Konstantinos Brintakis, Maria Sygletou, Kyriaki Savva, Nikolaos Livakas, Michaila Akathi Pantelaiou, Zhiya Dang, Alexandros Lappas, Liberato Manna, and Emmanuel Stratakis. "Laser-Induced Morphological and Structural Changes of Cesium Lead Bromide Nanocrystals." Nanomaterials 12, no. 4 (February 20, 2022): 703. http://dx.doi.org/10.3390/nano12040703.

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Metal halide perovskite nanocrystals, an emerging class of materials for advanced photonic and optoelectronic applications, are mainly fabricated with colloidal chemistry routes. On the quest for new properties according to application needs, new perovskite systems of various morphologies and levels of doping and alloying have been developed, often also involving post-synthesis reactions. Recently, laser irradiation in liquids has been utilized as a fast method to synthesize or transform materials and interesting laser-induced transformations on nanocrystals were induced. These studies in general have been limited to small nanocrystals (~15 nm). In the case of halide perovskites, fragmentation or anion exchange have been observed in such laser-based processes, but no crystal structure transformations were actually observed or deliberately studied. Nanocrystals are more sensitive to light exposure compared to the corresponding bulk crystals. Additional factors, such as size, morphology, the presence of impurities, and others, can intricately affect the photon absorption and heat dissipation in nanocrystal suspensions during laser irradiation. All these factors can play an important role in the final morphologies and in the time required for these transformations to unfold. In the present work, we have employed a 513 nm femtosecond (fs) laser to induce different transformations in large nanocrystals, in which two phases coexist in the same particle (Cs4PbBr6/CsPbBr3 nanohexagons of ~100 nm), dispersed in dichlorobenzene. These transformations include: (i) the exfoliation of the primary nanohexagons and partial anion exchange; (ii) fragmentation in smaller nanocubes and partial anion exchange; (iii) side-by-side-oriented attachment, fusion, and formation of nanoplatelets and complete anion exchange; (iv) side-by-side attachment, fusion, and formation of nanosheets. Partial or complete Br-Cl anion exchange in the above transformations was triggered by the partial degradation of dichlorobenzene. In addition to the detailed analysis of the various nanocrystal morphologies observed in the various transformations, the structure–photoluminescence relationships for the different samples were analyzed and discussed.

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KORNOWSKI, A., M. GIERSIG, R. VOGEL, A. CHEMSEDDINE, and H. WELLER. "ChemInform Abstract: Nanometer-Sized Colloidal Germanium Particles: Wet-Chemical Synthesis, Laser-Induced Crystallization and Particle Growth." ChemInform 25, no. 4 (August 19, 2010): no. http://dx.doi.org/10.1002/chin.199404021.

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Gajdardziska-Josifovska, M., V. Lazarov, J. Reynolds, and V. V. Yakovlev. "Photon and Electron Beam Induced Phase Transformations in CDS Nanocrystals." Microscopy and Microanalysis 6, S2 (August 2000): 18–19. http://dx.doi.org/10.1017/s143192760003258x.

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One of the great challenges of nanotechnology is how to produce and modify objects at nanoscale dimensions. The search for physical and chemical methods for controlled synthesis, modification and characterization of semiconductor nanocrystals is of special interest due to their novel electronic and optical properties. Recently we have achieved the first laser-induced phase transformation in semiconductor nanocrystals [1], irradiating colloidal solutions of CdS nanocrystals with 7 ns pulses of 532 nm wavelength. We used established wet-chemistry methods to synthesize the CdS nanocrystals, and a combination of electron microscopy methods to determine the structure, size and composition of the nanocrystals. In the present paper we report a wavelength dependence of the laser-induced phase transformations in CdS. We also explore electron-induced transformations in comparison with their photon counterparts.Aqueous colloidal solutions of CdS nanocrystals were prepared by mixing of CdCl2 with Na2S in the presence of Sodium Mercaptoacetate and HC1 [2].

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39

Lim, Jaemook, Jimin Ham, Woohyun Lee, Eunseung Hwang, Won Chul Lee, and Sukjoon Hong. "A Transformative Gold Patterning through Selective Laser Refining of Cyanide." Nanomaterials 11, no. 8 (July 26, 2021): 1921. http://dx.doi.org/10.3390/nano11081921.

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Gold is an essential noble metal for electronics, and its application area is increasing continuously through the introduction of gold nanoparticle ink that enables rapid prototyping and direct writing of gold electrodes on versatile substrates at a low temperature. However, the synthesis of gold nanoparticles has certain limitations involving high cost, long synthesis time, large waste of material, and frequent use of chemicals. In this study, we suggest simultaneous laser refining of gold cyanide and selective fabrication of gold electrodes directly on the substrate without a separate synthesis step. Gold cyanide is commonly the first product of gold from the primitive ore, and the gold can be extracted directly from the rapid photothermal decomposition of gold cyanide by the laser. It was confirmed that laser-induced thermocapillary force plays an important role in creating the continuous gold patterns by aligning the refined gold. The resultant gold electrodes exhibited a low resistivity analogous to the conventional direct writing method using nanoparticles, and the facile repair process of a damaged electrode was demonstrated as the proof-of-concept. The proposed transformative approach for gold patterning, distinguished from the previous top-down and bottom-up approaches, has the potential to replace the well-known techniques and provide a new branch of electrode manufacturing scheme.

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Pereira, Sónia O., Nuno F. Santos, Alexandre F. Carvalho, António J. S. Fernandes, and Florinda M. Costa. "Electrochemical Response of Glucose Oxidase Adsorbed on Laser-Induced Graphene." Nanomaterials 11, no. 8 (July 23, 2021): 1893. http://dx.doi.org/10.3390/nano11081893.

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Carbon-based electrodes have demonstrated great promise as electrochemical transducers in the development of biosensors. More recently, laser-induced graphene (LIG), a graphene derivative, appears as a great candidate due to its superior electron transfer characteristics, high surface area and simplicity in its synthesis. The continuous interest in the development of cost-effective, more stable and reliable biosensors for glucose detection make them the most studied and explored within the academic and industry community. In this work, the electrochemistry of glucose oxidase (GOx) adsorbed on LIG electrodes is studied in detail. In addition to the well-known electroactivity of free flavin adenine dinucleotide (FAD), the cofactor of GOx, at the expected half-wave potential of −0.490 V vs. Ag/AgCl (1 M KCl), a new well-defined redox pair at 0.155 V is observed and shown to be related to LIG/GOx interaction. A systematic study was undertaken in order to understand the origin of this activity, including scan rate and pH dependence, along with glucose detection tests. Two protons and two electrons are involved in this reaction, which is shown to be sensitive to the concentration of glucose, restraining its origin to the electron transfer from FAD in the active site of GOx to the electrode via direct or mediated by quinone derivatives acting as mediators.

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Li, Yu Xin, and Pei Kang Bai. "Study on Microstructure and Mechanical Properties of Ni/TiC Composites by Laser Induced Self-Propagating High-Temperature Synthesis." Advanced Materials Research 239-242 (May 2011): 1072–75. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.1072.

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Ni/TiC composites have been produced using laser induced self-propagating high-temperature synthesis. The chemical composition and microstructure were investigated by means of X-ray diffraction and scanning electron microscope. The sintered density and mechanical properties such as bending strength and micro-hardness were also measured. The results showed that the synthesized products were consisted of TiC and Ni phases, which indicated that the TiC was synthesized by the in-situ reaction. Moreover, the results revealed that the sintered density increased and the micro-hardness and bending strength of the synthesized products gradually decreased with the increasing of Ni contents.

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Lee, Jun-Uk, Jeong-hoon Lee, Chan-Woo Lee, Su-Chan Cho, Sung-Moo Hong, Yong-won Ma, Sung-Yeob Jeong, and Bo-Sung Shin. "Green Synthesis of Laser-Induced Graphene with Copper Oxide Nanoparticles for Deicing Based on Photo-Electrothermal Effect." Nanomaterials 12, no. 6 (March 14, 2022): 960. http://dx.doi.org/10.3390/nano12060960.

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Homogenously dispersed Cu oxide nanoparticles on laser-induced graphene (LIG) were fabricated using a simple two-step laser irradiation. This work emphasized the synergetic photo-electrothermal effect in Cu oxide particles embedded in LIG. Our flexible hybrid composites exhibited high mechanical durability and excellent thermal properties. Moreover, the Cu oxide nanoparticles in the carbon matrix of LIG enhanced the light trapping and multiple electron internal scattering for the electrothermal effect. The best conditions for deicing devices were also studied by controlling the amount of Cu solution. The deicing performance of the sample was demonstrated, and the results indicate that the developed method could be a promising strategy for maintaining lightness, efficiency, excellent thermal performance, and eco-friendly 3D processing capabilities.

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43

Cheng, J., Xiao Ping Zou, Guang Zhu, Mao Fa Wang, and Yi Su. "High-Quality Single-Walled Carbon Nanotubes Synthesized by Floating Catalyst Chemical Vapor Depostion." Advanced Materials Research 47-50 (June 2008): 746–49. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.746.

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High-quality single-walled carbon nanotubes (SWNTs) are a key aspect in the emerging field nanotechnology. Although many approaches have been developed, the research on the synthesis of SWNTs is still needed. In this study, we report the synthesis of high-quality SWNTs by floating catalyst chemical vapor deposition, which employs ferrocene as the catalyst precursors. We obtained massive deposits at low temperature region. The deposits were characterized by scanning electron microscopy, transmission electron microscopy, and visual laser Raman spectroscopy. The Raman spectrum obtained from raw deposits shows clear radial breathing mode at the range from 180cm-1 to 300cm-1 and high-intensity graphite mode at 1577.7cm-1 with a shoulder at 1550.5cm-1, and almost no detectable peak around at 1545cm-1, which is induced by defects, is observed. These results indicate that the deposits are high-quality SWNTs.

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Khartchenko, S. S., and A. I. Kuzmin. "A mathematical model of laser-induced synthesis of ultrafine SiC powders." Symposium (International) on Combustion 26, no. 2 (1996): 1845–49. http://dx.doi.org/10.1016/s0082-0784(96)80005-1.

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Okla, Mohammad K., Mohamed A. El-Tayeb, Ahmed Ali Qahtan, Mostafa A. Abdel-Maksoud, Yahya B. Elbadawi, Mohamed Khamis Alaskary, Mansour A. Balkhyour, Abdelrahim H. A. Hassan, and Hamada AbdElgawad. "Laser Light Treatment of Seeds for Improving the Biomass Photosynthesis, Chemical Composition and Biological Activities of Lemongrass Sprouts." Agronomy 11, no. 3 (March 4, 2021): 478. http://dx.doi.org/10.3390/agronomy11030478.

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Compared to seeds and mature plants, sprouts are well characterized based on their nutritive values and biological properties. Moreover, laser light application is known to be a promising approach to improving plant growth, photosynthesis, and nutraceutical values. However, no studies have investigated the phytochemicals and biological activity of lemongrass (Cymbopogon proximus (Hochst. ex A.Rich.) Chiov.) sprouts or the further improvement of their quality by applying laser light treatment. We carried out a preliminary experiment for the optimization of laser treatment conditions, finding that a helium neon (He–Ne) laser at 632 nm and 5 mW for 5 min provided the most favorable conditions. We then investigated fresh weight, photosynthetic reactions, and primary and secondary metabolites, including sugars, amino acids, organic acids, essential oils, and phenolic compounds. Moreover, we studied the effect of laser light-induced changes in chemical compositions on the antioxidant, anti-diabetic, and anti-cholesterol activities of Cymbopogon proximus sprouts grown from laser-treated seeds. Laser light treatment increased the photosynthesis and respiration and hence the fresh weight of Cymbopogon proximus sprouts. Overall, sprouting increased most bioactive primary and secondary metabolites as compared to seeds. Increased photosynthesis by laser light improved carbon allocation and raised non-structural carbohydrates, which in turn led to improved synthesis of amino acids, organic acids, and essential oils, as well as phenolic and flavonoid compounds. As a result, laser light significantly improved the antioxidant capacity in terms of increasing the levels of ferric reducing antioxidant power (FRAP) (from 9.5 to 21 µmole trolox/g fresh weight (FW)), oxygen radical absorbance (ORAC) (from 400 to 1100 µmole trolox/100 g FW), and DPPH (from 5% to 25% of inhibation) and enhanced the hypocholesterolemic and antidiabetic activity through increasing the percentage of cholesterol micellar solubility (CMS) inhibition (from 42% to 62%) and glycemic index (from 33 to 17 µmole/g) over sprouts and seeds. In conclusion, the synergism of seed laser treatment and sprouting induced the health-promoting bioactive compounds in Cymbopogon proximus as compared to seeds, which can be applied at a large scale to improve the biochemical, physiological, and nutraceutical values of medicinal and crop sprouts.

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Hristovski, Ilija R., Luke A. Herman, Michael E. Mitchell, Nikolai I. Lesack, Jason Reich, and Jonathan F. Holzman. "Manifestations of Laser-Induced Graphene under Ultraviolet Irradiation of Polyimide with Varied Optical Fluence." Nanomaterials 12, no. 8 (April 7, 2022): 1241. http://dx.doi.org/10.3390/nano12081241.

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In this work, we put forward a rigorous study on ultraviolet (355-nm) laser irradiation of polyimide for the realization of high-quality laser-induced graphene (LIG) with micron-scale features. High-quality material and micron-scale features are desirable—but often at odds—given that small features demand tightly focused beam spots, with a predisposition to ablation. As such, we investigate the synthesis of LIG by correlating the material characteristics, as gleaned from scanning electron microscopy and Raman spectroscopy, to the incident optical fluence, as a measure of applied optical energy per unit area. The study reveals that high-quality LIG, with ratios of Raman 2D-to-G peak heights approaching 0.7, can be synthesized with micron-scale features, down to 18 ± 2 μm, given suitable attention to the optical fluence. Optimal characteristics are seen at optical fluences between 40 and 50 J/cm2, which promote graphenization and minimize ablation. It is hoped that these findings will lay a foundation for the application of LIG in future integrated technologies.

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Baykusheva, Denitsa, Daniel Zindel, Vít Svoboda, Elias Bommeli, Manuel Ochsner, Andres Tehlar, and Hans Jakob Wörner. "Real-time probing of chirality during a chemical reaction." Proceedings of the National Academy of Sciences 116, no. 48 (November 13, 2019): 23923–29. http://dx.doi.org/10.1073/pnas.1907189116.

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Chiral molecules interact and react differently with other chiral objects, depending on their handedness. Therefore, it is essential to understand and ultimately control the evolution of molecular chirality during chemical reactions. Although highly sophisticated techniques for the controlled synthesis of chiral molecules have been developed, the observation of chirality on the natural femtosecond time scale of a chemical reaction has so far remained out of reach in the gas phase. Here, we demonstrate a general experimental technique, based on high-harmonic generation in tailored laser fields, and apply it to probe the time evolution of molecular chirality during the photodissociation of 2-iodobutane. These measurements show a change in sign and a pronounced increase in the magnitude of the chiral response over the first 100 fs, followed by its decay within less than 500 fs, revealing the photodissociation to achiral products. The observed time evolution is explained in terms of the variation of the electric and magnetic transition-dipole moments between the lowest electronic states of the cation as a function of the reaction coordinate. These results open the path to investigations of the chirality of molecular-reaction pathways, light-induced chirality in chemical processes, and the control of molecular chirality through tailored laser pulses.

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Li, Chun Ping, Hao Ran Ba, and Kun Jin. "Effects of Fe Doping on the Crystal Structures and Photoluminescence of ZnO Nanorods." Key Engineering Materials 636 (December 2014): 105–9. http://dx.doi.org/10.4028/www.scientific.net/kem.636.105.

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The 5% Fe-doped ZnO nanorods (Zn0.95Fe0.05O) were prepared successfully by the wet-chemical synthesis method. Structure and morphology characterization were demonstrated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Laser power dependent photoluminescence (PL) spectra were measured to study the electronic structures of the Fe-doped ZnO-based diluted magnetic semiconductors. The contraction of lattice constant and structured green-yellow-red emissions were analyzed. Such investigations confirmed that the induced defects or impurities originating from Fe ions.

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Li, Chen, Jie Hu, Lan Jiang, Chenyang Xu, Xiaowei Li, Yunfeng Gao, and Liangti Qu. "Shaped femtosecond laser induced photoreduction for highly controllable Au nanoparticles based on localized field enhancement and their SERS applications." Nanophotonics 9, no. 3 (January 23, 2020): 691–702. http://dx.doi.org/10.1515/nanoph-2019-0460.

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AbstractGold nanoparticles (Au NPs) have a wide range of applications because of their localized surface plasmon resonance properties. Femtosecond laser is considered to be an effective method for preparing Au NPs because of its characteristics of ultrashort irradiation periods and ultrahigh intensities. In this study, a novel method is proposed to produce an Au NP-attached substrate using the spatially and temporally shaped femtosecond laser. Laser-induced periodic surface structures (LIPSS) are designed to obtain the localized optical field enhancement, which leads to the femtosecond laser spatially reshaping, enabling the deposition of Au NPs by photoreduction on silicon substrates. The Au NPs prepared by this method exhibit morphological controllability and chemical stability, especially excellent spatial selectivity and uniformity, resulting in the tunable and stable surface-enhanced Raman scattering (SERS) applications. Also, the temporally shaped femtosecond pulses are introduced to further increase the enhancement factors of the SERS. This method successfully achieves the controllable morphology synthesis and selective deposition of Au NPs on the substrate simultaneously, which provides a promising candidate for SERS substrates fabrication, and holds potential applications in optoelectronics, such as molecular detection and biosensors.

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Park, Sulgiye, Iwnetim I. Abate, Jin Liu, Chenxu Wang, Jeremy E. P. Dahl, Robert M. K. Carlson, Liuxiang Yang, et al. "Facile diamond synthesis from lower diamondoids." Science Advances 6, no. 8 (February 2020): eaay9405. http://dx.doi.org/10.1126/sciadv.aay9405.

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Carbon-based nanomaterials have exceptional properties that make them attractive for a variety of technological applications. Here, we report on the use of diamondoids (diamond-like, saturated hydrocarbons) as promising precursors for laser-induced high-pressure, high-temperature diamond synthesis. The lowest pressure and temperature (P-T) conditions that yielded diamond were 12 GPa (at ~2000 K) and 900 K (at ~20 GPa), respectively. This represents a substantially reduced transformation barrier compared with diamond synthesis from conventional (hydro)carbon allotropes, owing to the similarities in the structure and full sp3 hybridization of diamondoids and bulk diamond. At 20 GPa, diamondoid-to-diamond conversion occurs rapidly within <19 μs. Molecular dynamics simulations indicate that once dehydrogenated, the remaining diamondoid carbon cages reconstruct themselves into diamond-like structures at high P-T. This study is the first successful mapping of the P-T conditions and onset timing of the diamondoid-to-diamond conversion and elucidates the physical and chemical factors that facilitate diamond synthesis.

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Journal articles on the topic 'Pulsed-laser Induced Chemical Synthesis'

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