External field assisted laser ablation in liquid an efficient strategy for nanocrystal synthesis and nanostructure assembly ( ) DOI http //dx doi org/10 1016/j pmatsci 2017 02 004 Reference JPMS 436 T[.]
DOI: Reference: http://dx.doi.org/10.1016/j.pmatsci.2017.02.004 JPMS 436 To appear in: Progress in Materials Science Received Date: Revised Date: Accepted Date: 27 January 2016 20 February 2017 21 February 2017 Please cite this article as: Xiao, J., Liu, P., Wang, C.X., Yang, G.W., External field-assisted laser ablation in liquid: an efficient strategy for nanocrystal synthesis and nanostructure assembly, Progress in Materials Science (2017), doi: http://dx.doi.org/10.1016/j.pmatsci.2017.02.004 This is a PDF file of an unedited manuscript that has been accepted for publication As a service to our customers we are providing this early version of the manuscript The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain External field-assisted laser ablation in liquid: an efficient strategy for nanocrystal synthesis and nanostructure assembly J Xiao, P Liu, C X Wang, G W Yang* State Key Laboratory of Optoelectronic Materials and Technologies, Nanotechnology Research Center, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, P R China *Corresponding author: stsygw@mail.sysu.edu.cn Abstract Laser ablation in liquid (LAL) has received considerable attention over the last decade, and is gradually becoming an irreplaceable technique to synthesize nanocrystals and fabricate functional nanostructures because it can offer effective solutions to some challenges in the field of nanotechnology The goal of this review is to offer a comprehensive summary of recent developments of LAL in nanocrystal synthesis and nanostructure fabrication First, we will introduce the fundamental processes of microsecond, nanosecond, and femtosecond LAL, and how the active species act differently in plasma, cavitation bubbles, and droplets in the different LAL processes Second, a variety of LAL-based techniques for nanomaterials synthesis and processing are presented, such as electric-, magnetic-, and temperature-field LAL, as well as electrochemically assisted LAL, pulsed laser deposition in liquid, and laser writing of nanopatterns in liquid Third, new progress in LAL-generated nanomaterials is described Fourth, we emphasize five applications of LAL-generated nanomaterials that have emerged recently in the fields of optics, magnetism, environment, energy, and biomedicine Finally, we consider the core advantages of LAL, the limitations of LAL and corresponding solutions, and the future directions in this promising research area Contents Introduction Laser ablation of a solid target in liquid 13 2.1 Fundamental physical process 14 2.1.1 Millisecond-laser ablation in liquid and melting process 14 2.1.2 Nanosecond-laser ablation in liquid and plasma formation 16 2.1.3 Picosecond-laser ablation in liquid and cavitation bubble 21 2.1.4 Femtosecond-laser ablation in liquid and multiple processes 23 2.2 Fundamental chemical process 26 2.2.1 Chemical reactions in plasma 26 2.2.2 Chemical reactions at interface between solid and liquid 30 LAL-based nanomaterials preparation and processing 33 3.1 Electrical field-assisted LAL for shape controlling of metal oxide nanocrystals 33 3.1.1 Metal oxides semiconductor nanocrystals with various shapes 33 3.1.2 Influence of electrical field on shape formation of nanocrystals 34 3.2 Electrical field-assisted LAL for nanostructures fabrication 37 3.2.1 Functional nanostructures of metal oxides fabrication 37 3.2.2 Orientated attachment mechanism of nanostructures fabrication 38 3.3 Room temperature ripening-assisted LAL for nanostructures fabrication 39 3.3.1 One-and two-dimensional nanostructures fabrication 39 3.3.2 Ostwald ripening mechanism of nanostructures fabrication 40 3.4 Electrochemistry-assisted LAL for complex nanostructures fabrication 44 3.4.1 Fabricating simple polyoxometalate nanostructures 44 3.4.2 Chemical reactions in fabrication of nanostructures 46 3.5 Magnetic field-assisted LAL for magnetic nanochains fabrication 48 3.5.1 Fabrication of one-dimensional chain bundle of magnetic nanoparticles 48 3.5.2 Magnetic field induced orientated attachment mechanism 50 Nanopatterning in liquid 54 4.1 Pulsed-laser deposition in liquid for nanopattern fabrication 54 4.1.1 Pulsed-laser deposition in liquid 54 4.1.2 Fabrication of nanoparticles pattern on transparent substrates 54 4.2 Laser-writing of functional nanopatterns in liquid 55 4.2.1 Fabrication of nanopatterns with heterostructure 55 4.2.2 Phase transformation upon laser-writing in liquid 56 New progress in nanomaterials synthesis based on LAL 57 5.1 Nanoparticle–polymer composites 57 5.2 Doped semiconductor nanocrystals 60 5.3 Submicrometer spherical particles 63 5.4 Monodispersed colloid quantum dots 66 Applications in nanocrystals synthesis and nanostructure fabrication 68 6.1 Functional nanostructures for optics 69 6.1.1 Fluorescence emission 69 6.1.2 Visible light scattering 73 6.1.3 Nonlinear optics 75 6.2 Functional nanostructures for magnetics 75 6.3 Functional nanostructures for environmental applications 77 6.3.1 Adsorption 77 6.3.2 Photocatalytic degradation 79 6.3.3 Sensing 83 6.4 Functional nanostructures for green energy 87 6.4.1 Supercapacitor 87 6.4.2 Lithium-ion battery 88 6.4.3 Solar cell 89 6.4.4 Hybrid light-emitting diode 91 6.4.5 Water-splitting photocatalyst 92 6.4.6 Electrocatalyst 94 6.5 Functional nanostructures for biomedicine 96 6.5.1 Biomolecules carrier 96 6.5.2 Positive contrast agent 97 6.5.3 Bio-recognition 99 Conclusion and Perspective 100 7.1 Main advantages of LAL 100 7.1.1 Surface .100 7.1.2 Metastable structures 104 7.2 The main disadvantages of LAL and methods to address them 106 7.2.1 Productivity 106 7.2.2 Size and dispersity control 109 7.3 Future directions of LAL 111 7.3.1 Mechanisms exploration 111 7.3.2 Extending applications .113 Acknowledgments 118 References 119 Introduction Although nanomaterials have been investigated extensively in recent decades, researchers still face fundamental challenges For example, how to control the phase, size, and shape of building blocks in nanomaterials synthesis, how to facilely fabricate functional nanostructures using these building blocks, and how to achieve the transformation from simple synthesis of nanomaterials to complex fabrication of functional nanounits [1–4] To address these issues, researchers have developed a series of conventional techniques to achieve a variety of functional objectives; for example, thermal chemical vapor transport based on the vapor–liquid–solid process for nanowires [5–8], solution-based chemical reactions for nanocrystals [9–11], and template assembly based on DNA molecules to obtain complex nanostructures [12–14] Among these methods, laser ablation in liquid (LAL) has drawn great attention in recent years because of its distinctive geometries [15–20] These include novel metastable nanophases and nanoparticle colloids with extremely high stability and purity LAL is a facile general technique with an almost unlimited variety of prospective materials and solvents [16,17] Compared with conventional production processes of nanomaterials, such as gas-phase methods, which usually produce agglomerated micro- or nanopowders that are difficult to disperse to form functional matrices, and chemical methods, which generally provide nanomaterials with impurities originating from additives and precursor reaction products, LAL has the following advantages (i) LAL is a chemically simple and clean because the process has little byproduct formation, simple starting materials, and no need for catalyst These factors ensure production of highly pure clean surfaces that often possess high surface activity [21] (ii) LAL is conducted under ambient conditions and does not require extreme temperature and/or pressure Despite the mild conditions, LAL still allows access to a variety of metastable phases that may not usually be attainable (iii) LAL is a facile general method with an almost unlimited scope of suitable materials and solvents Because new phase formation in LAL involves both a liquid and solid, researchers can choose and combine interesting solid targets and liquids to synthesize nanocrystals and fabricate nanostructures for fundamental research and potential applications [22] (iv) In some cases, the phase, size, and shape of nanostructures can be readily controlled by tuning laser parameters and assisting factors, allowing both nanocrystal synthesis and nanostructure fabrication in one-step For example, Koshizaki et al [23] used laser selective heating to synthesize submicron spheres of different size by changing the laser parameters Yang and colleagues used magnetic field-assisted laser ablation in liquid (MFLAL) [23] to fabricate microfibers of an iron–carbon composite [24], submicron Co3C particle chains [25], and one-dimensional chains of iron-based bimetallic alloying nanoparticles [26] Therefore, LAL has been proven a general and effective technique to synthesize nanomaterials and fabricate functional nanostructures Note that the achievements realized in this field in very recent years have greatly exceeded those made in the previous two decades Therefore, it is timely to review the recent progress of LAL applications in the preparation and processing of nanomaterials Next we briefly summarize the recent developments in LAL Fig 1a and b show the increasing number of articles and corresponding citations from 2000 to Nov 1st, 2016 in the field of LAL These data were obtained by searching the entry “Laser ablation in liquids” in the Web of Science Using different search string and data set refinement may provide different results [27] These two indexes steadily increase over the years, indicating the rapid development of LAL research Fig 2a and b present the advanced optical detection techniques used in LAL, such as optical emission spectroscopy for plasma characterization, the fast shadowgraph method to probe plasma and cavitation bubble dynamics, laser scattering to determine the delivery mechanisms of the produced materials in the liquids, and small-angle X-ray scattering to observe nanoparticle formation in a cavitation bubble [28,29] Additionally, researchers have developed various innovative types of equipment to achieve LAL under extreme conditions Fig 2c depicts a photograph of a high-pressure cell designed for in situ experiments at temperatures up to 400 K and pressures up to 30 MPa [30] All these experimental and detection devices greatly enrich the research on mechanism exploration and nanocrystal synthesis The introduction of new laser, detection, and experimental devices makes LAL become a more powerful and efficient approach to fabricate new nanocrystals and explore synthetic mechanisms Because of the almost unlimited number of materials and various liquid solvents suitable for LAL, it has been used to synthesize a huge variety of advanced materials [23,31] Meanwhile, picosecond (ps) lasers that operate .. .External field- assisted laser ablation in liquid: an efficient strategy for nanocrystal synthesis and nanostructure assembly J Xiao, P Liu, C X Wang, G W Yang* State Key Laboratory... size, and shape of nanostructures can be readily controlled by tuning laser parameters and assisting factors, allowing both nanocrystal synthesis and nanostructure fabrication in one-step For example,... researchers can choose and combine interesting solid targets and liquids to synthesize nanocrystals and fabricate nanostructures for fundamental research and potential applications [22] (iv) In some