液相激光烧蚀法制备纳米材料的研究进展

液相激光烧蚀方法,主要是利用激光与液态介质相互作用、产生局域高温高压非平衡过程而获得纳米材料的方法,能够有效合成常规手段无法合成的新型纳米材料。阐述了液相激光烧蚀法(包括非反应性液相激光烧蚀和反应性液相激光烧蚀)制备纳米材料的基本原理和国内外研究现状,并指出这一领域存在的主要问题与发展方向。     

飞秒激光加工低维纳米材料及应用

飞秒激光具有脉宽超短、瞬时功率密度超高、非线性加工的特点,对低维纳米材料的制备和加工有着独特的优势,且具有广泛的材料适应性,能够方便快捷地针对需要精确靶向定位和图案化加工的纳米材料做出加工策略。本文综述了飞秒激光对低维纳米材料的制备加工和改性的研究现状,介绍了时空整形飞秒脉冲激光方法下制备的功能性量子点、纳米线、二维薄膜材料,和这些材料在化学催化、生物化学检测、生物相容性及电子器件等领域的应用,分析讨论了激光液相烧蚀制备纳米材料和集成化器件加工当前所面临的挑战和今后的研究重点。     

真空及大气下激光对复合材料的烧蚀试验对比

激光与物质相互作用受到环境因素的影响。为了研究真空及大气环境下激光对复合材料的烧蚀模式和烧蚀规律,开展了激光辐照碳纤维复合材料对比试验。在不同辐照能量水平下,研究了两种环境中激光对复合材料的烧蚀特征,获得了复合材料瞬态温度响应数据,并对烧蚀样品进行了显微观测。试验结果表明,环境因素的影响与入射激光能量水平紧密相关。在低辐照能量水平下,复合材料表面烧蚀形貌具有差异,但瞬态热响应非常接近。在较高辐照能量水平下,复合材料烧蚀形貌差异较大:在真空环境下复合材料的环氧树脂发生热解和挥发,碳纤维束发生脱层;在大气环境下复合材料的环氧树脂发生明显的氧化反应,碳纤维束轻微脱层。最后,结合样品显微观测结果,分析了真空及大气环境下激光对复合材料烧蚀模式差异的原因,为建立激光烧蚀理论模型提供了参考。     

纳米光子学材料漫谈

评述纳米光子学材料的制备.纳米光子学材料的种类繁多,不同的纳米形态、结构具有不同的特性,其制备方法更是成千上万种.列举20种形态的纳米光子学材料,阐明它们的制备方法、特性和应用前景.     

靶面激光光斑尺寸原位测量的研究

提供了一种简便易行的靶面激光光斑尺寸原位测量的方法。从高斯光束的横向光强分布特性出发,建立了激光烧蚀斑半径与辐照激光能量、光斑尺寸、烧蚀阈值间的关系式,模拟分析发现辐照激光光斑尺寸对烧蚀斑半径随辐照能量变化曲线有较大影响。对于脉宽为2 ms,波长为1064 nm的激光,实验测量了不同能量激光辐照下相纸烧蚀斑半径,并用推导出的关系式拟合测量数据,获得了靶面处光斑尺寸和样品烧蚀阈值。同时,也测量了不同位置处的光斑尺寸和样品烧蚀阈值,对高斯光束束腰位置和样品烧蚀阈值的光斑尺寸效应进行了验证。研究结果表明该技术结果可靠,简单高效。该技术可以为高能激光与固体物质相互作用的基础研究和激光加工等应用领域中实现简单方便地测量靶面光斑尺寸提供帮助。     

飞秒激光扫描不同温度下的硅片诱导形成微结构的差别

不同温度下利用钛宝石激光器输出的飞秒激光脉冲(脉宽42fs,中心波长800nm,最大单脉冲能量3.6mJ),通过扫描方式在硅表面诱导产生表面微结构。采用光学显微镜和扫描电镜观察飞秒激光诱导硅表面微结构的形貌,发现不同温度下硅片表面形成的微结构区域和形貌出现明显的差异。根据观测结果,分析比较了不同温度条件下硅材料微结构形成的能量阈值。随着温度升高,形成的微结构区域减小,飞秒激光诱导形成硅表面微结构的能量阈值升高。这对于研究飞秒激光与物质的相互作用有一定的参考价值,也能对将来实现硅表面微结构的制作提供参考。     

Emerging Mono-Elemental Bismuth Nanostructures: Controlled Synthesis and Their Versatile Applications

Bismuth (Bi), as a nontoxic and inexpensive diamagnetic heavy metal, has recently been utilized for the preparation of a variety of nanomaterials, such as nanoparticles, nanowires, nanotubes, nanosheets, etc., with a tunable bandgap, unique structure, excellent physicochemical properties, and compositional features for versatile properties, such as near-infrared absorbance, high X-ray attenuation coefficient, excellent photothermal conversion efficiency, and a long circulation half-life. These features have endowed mono-elemental Bi nanomaterials with desirable performances for electronics/optoelectronics, energy storage and conversion, catalysis, nonlinear photonics, sensors, biomedical applications, etc. This review summarizes the controlled synthesis of mono-elemental Bi nanomaterials with different shapes and sizes, highlights the state-of-the-art progress of the desired applications of mono-elemental Bi nanomaterials, and presents some personal insights on the challenges and future opportunities in this research area. It is hoped that the controllable manipulation techniques of Bi nanomaterials, along with their unique properties, can shed light on the next-generation devices based on Bi nanostructures and Bi-related nanomaterials.     

Ternary Oxide Nanocrystals: Universal Laser‐Hydrothermal Synthesis,Optoelectronic and Electrochemical Applications

Ternary oxide nanocrystals (TONs) have received growing attention for their great potential applications in optoelectronics and electrochemistry despite the current scarcity of universal, facile, and green synthesis methods. Here, we introduce a universal laser‐hydrothermal approach for various TONs and demonstrate their potential for high‐performance photodetectors (PDs) and pseudocapacitors. The obtained clean surface is derived by laser ablation in liquid (LAL) and subsequent hydrothermal growth. The LAL‐generated precursors contain many kinds of highly reactive species, including H⁺, OH^?, metal ions, and clusters, which facilitate the fast and facile formation of various TONs in the subsequent hydrothermal process. The universality of the method is systematically proven by the synthesis of a series of TONs, including Zn₂GeO₄, NiCo₂O₄, Zn₂SnO₄, ZnFe₂O₄, ZnMnO₃, and Fe₂GeO₄. Significantly, the absence of chemical additives, such as surfactants, guarantees highly clean surfaces, which further benefits the electron transport through the nanocrystals, and thus in the resultant devices. This is also exemplified by a Zn₂GeO₄‐nanorod‐based, deep‐ultraviolet PD and NiCo₂O₄ nanocrystal supercapacitors.     

飞秒激光辅助制备熔石英表面的网格状微流体

报道了一种利用飞秒激光直写后再用化学腐蚀熔石英表面制备得到网格状微流体沟道,然后在其表面覆盖一层PDMS薄膜制备网格状半密闭微流体通道的方法。微流体沟道的形成机制可以定义为飞秒激光辐照导致基底材料改性,而改性区域对HF水溶液的溶解度增强。使用光学显微镜和扫描电子显微镜(SEM)表征了网格状微流体通道的形貌。此外,为了测试该微流体结构的流动特性,进行了液体注入实验。     

钛的ns脉冲激光氮化

报道用５ｎｓ脉冲激光通过激光气体合金化形成氮化钛的研究。通过探测发射光谱观察了氨化过程，用光学显微镜和扫描电子显微镜观察了氨化层的表面形貌，激光烧蚀飞行时间质谱和Ｘ射线衍射标征了氮化层。激光脉冲起着熔化钛表面和激活氮的作用，导致钛的液相氮化。同时，也发现生成的氨化层是富Ｔｉ的，由δ－ＴｉＮ和α—Ｔｉ组成。     

3D Microfluidic Surface‐Enhanced Raman Spectroscopy (SERS) Chips Fabricated by All‐Femtosecond‐Laser‐Processing for Real‐Time Sensing of Toxic Substances

A novel all‐femtosecond‐laser‐processing technique is proposed for the fabrication of 2D periodic metal nanostructures inside 3D glass microfluidic channels, which have applications to real‐time surface‐enhanced Raman spectroscopy (SERS). In the present study, 3D glass microfluidic channels are fabricated by femtosecond‐laser‐assisted wet etching. This is followed by the space‐selective formation of Cu‐Ag layered thin films inside the microfluidic structure via femtosecond laser direct writing ablation and electroless metal plating. The Cu‐Ag films are subsequently nanostructured by irradiation with linearly polarized beams to form periodic surface structures. This work demonstrates that a double exposure to laser beams having orthogonal polarization directions can generate arrays of layered Cu‐Ag nanodots with dimensions as small as 25% of the laser wavelength. The resulting SERS microchip is able to detect Rhodamine 6G, exhibiting an enhancement factor of 7.3 × 10⁸ in conjunction with a relative standard deviation of 8.88%. This 3D microfluidic chip is also found to be capable of the real‐time SERS detection of Cd²⁺ ions at concentrations as low as 10 ppb in the presence of crystal violet. This technique shows significant promise for the fabrication of high performance microfluidic SERS platforms for the real‐time sensing of toxic substances with ultrahigh sensitivity.     

Si/Ge复合纳米结构的制备及表征

以Si和GeO2为原料,通过简单直接的热蒸发法在衬底的不同温度区域上得到了章鱼状、羽毛球状、拖把状等不同形貌的Si/Ge/O复合纳米结构。利用扫描电镜（SEM）研究了不同衬底区域纳米结构的形态,结合透射电镜（TEM）的明场像和扫描透射（STEM）模式下能谱的面扫描,系统地研究了不同形貌纳米结构的成分分布,并对生长过程进行了探讨。     

高能纳秒激光烧蚀单晶硅的微观结构

高能纳秒激光烧蚀硅时,往往会伴随着相爆炸过程,它决定了烧蚀的形貌特征。基于相爆炸的物理过程,分析了相应的烧蚀形貌：相爆炸的发生会使得硅材料发生大范围的去除,高温熔化材料的混合物向外喷溅,冷却形成放射状的冷却条,期间分布着冷却的球状微粒;超热液体的去除部位形成一个类似花瓣状坑,在坑中由于入射光与散射光的干涉形成条纹,其周期与激光光波相似。     

飞秒激光在6H-SiC表面诱导偏振依赖纳米结构特性研究

激光诱导偏振依赖纳米结构是一种有效实现纳米图案化的技术,并且一直备受研究者的青睐。利用飞秒激光微加工技术,对6H-SiC晶体表面激光诱导偏振依赖纳米结构特性进行了研究。通过改变入射激光加工偏振态和延迟时间样品表面诱导产生了直径约为150 nm的球形纳米颗粒、椭圆形纳米颗粒和空间周期约为150 nm的高空间频率表面条纹结构。实验结果表明,入射激光偏振特性会直接影响诱导产生的微结构形貌,并且优先入射的飞秒激光对最终产生的表面微结构形貌有决定性作用。初步探讨了偏振依赖纳米结构形成的物理机制,表面等离激元(surface plasmon polariton, SPP)在表面微纳米结构的产生过程中扮演着重要角色,研究结果对激光诱导表面周期结构(laser-induced periodic surface structures, LIPSS)可控制备具有重要意义。     

飞秒激光组装一维纳米材料及其应用

一维纳米材料具有众多优异的特性,是构建微纳米功能性器件的基石。实现一维纳米材料在二维和三维空间的高精度和高定向组装是充分发挥其应用潜力的关键,同时也是制造难点。在众多纳米材料组装技术中,飞秒激光直写诱导组装技术具有独特优势,可实现一维纳米材料在任意三维结构中的可设计、高定向及高精度的组装。首先简要介绍了一维纳米材料组装研究的背景,并总结了非激光直写组装技术的研究现状和存在的挑战,然后较详细介绍了飞秒激光直写技术在一维纳米材料组装研究中的进展,重点回顾了金属(包括Au和Ag纳米线)、半导体(包括CNTs和ZnO)一维纳米材料的飞秒激光直写组装及微纳光电子功能器件的制造。并讨论了诱导一维纳米材料定向排布的光学力和非光学力(包括剪切力、体积收缩应力和空间限制)的作用机理,理论计算和实验研究结果验证了飞秒激光诱导的非光学力作用是导致一维纳米材料定向排布的主要原因。最后探讨了目前飞秒激光组装技术面临的一些问题和未来在高精度纳米材料组装和三维功能器件集成方面的发展趋势。     

透明介质材料的超快激光微纳加工研究进展

透明介质材料具有高透光性、高耐热性和良好的耐腐蚀性,被广泛应用于航空航天、微电子器件和光学元件等领域,这些应用对透明介质材料微纳加工的精度与质量提出了一定的要求。超快激光具有超高的峰值强度与超短的脉冲持续时间,可突破衍射极限并极小化热影响区,具有出色的加工精度与加工质量,为透明介质材料的微纳尺度加工提供了多样化的手段。综述了透明介质材料的超快激光微纳加工研究进展,包括超快激光加工透明介质材料的内部结构、相关机理和应用领域三个方面,并对透明介质材料的超快激光微纳加工进行了总结与展望。     

激光烧蚀法制备准一维纳米材料

介绍了当前激光烧蚀法制备纳米丝、纳米管和纳米电缆的研究现状,讨论了准一维纳米材料激光烧蚀法制备的系统设备和制备条件,分析了激光烧蚀法制备准一维纳米材料的特点和发展趋势.认为准一维纳米材料是气相粒子在高温催化剂作用下生成的.激光烧蚀法具有洁净、可控性强及适应面广的特点.     

Etching‐Free Epitaxial Growth of Gold on Silver Nanostructures for High Chemical Stability and Plasmonic Activity

A robust method for epitaxial deposition of Au onto the surface of Ag nanostructures is demonstrated, which allows effective conversion of Ag nano­structures of various morphologies into Ag@Au counterparts, with the anisotropic ones showing excellent plasmonic properties comparable to the original Ag nanostructures while significantly enhanced stability. Sulfite plays a determining role in the success of this epitaxial deposition as it strongly complexes with gold cations to completely prevent galvanic replacement while it also remains benign to the Ag surface to avoid any ligand‐assisted oxidative etching. By using Ag nanoplates as an example, it is shown that the corresponding Ag@Au nanoplates possess remarkable plasmonic properties that are virtually Ag‐like, in clear contrast to Ag@Au nanospheres that exhibit much lower plasmonic activities than their Ag counterparts. As a result, they display high durability and activities in surface‐enhanced Raman scattering applications. This strategy may represent a general platform for depositing a noble metal on less stable metal nanostructures, thus opening up new opportunities in rational design of functional metal nanomaterials for a broad range of applications.     

重复激光脉冲作用下薄膜损伤演化规律研究

为了深入研究重复激光脉冲的能量效应对光学薄膜的烧蚀机理,采用实验观测与热力学分析相结合的方法进行了研究。通过观察光学薄膜烧蚀形貌随入射激光脉冲数量增加发生改变的典型形貌特征,分析了激光与等离子体相互作用的热力学过程,得到了在激光重复脉冲作用下光学薄膜的损伤特性及其演化规律。结果表明,薄膜在重复脉冲作用下,其表面会变得粗糙,这会大大增加对激光的吸收效应,从而加速了薄膜的破坏,最终被完全去除而露出基底;同时,烧蚀物会在热膨胀作用下向激光作用区域外扩散,在激光烧蚀中心区域外进行沉积,而形成更大范围的污染。由于激光光强为高斯分布,重复脉冲作用的效应主要是对在光束中心区域的薄膜进行集中烧蚀,会不断增加烧蚀的损伤程度,而对烧蚀面积的增加效应极为有限。这一研究结果为重复激光脉冲对薄膜烧蚀机理的建立提供了参考。     

532 nm nanosecond pulse laser triggered synthesis of ZnO2 nanoparticles via a fast ablation technique in liquid and their photocatalytic performance

Cubic phase zinc peroxide nanoparticles (ZnO₂ NPs) with an average diameter of ca. 9–15 nm have been synthesized via a fast nanosecond pulse laser ablation in liquid technique (PLAL), using H₂O₂ aqueous solution as the ablation media and a 532 nm pulsed laser as the irradiation source and low-cost zinc powder as the solid target. Both the laser energy and ablation time potentially have a substantial influence on the formation of ZnO₂ NPs. Due to its relatively high oxidation level as well as its hydrophilic wetting behavior, the as-synthesized ZnO₂ NPs exhibit efficient photocatalytic degradation ability of Rhodamine B (RB) whilst remaining stable to photodegradation. The possible mechanisms of the photocatalytic behavior have been discussed in what follows.