低维氮化硼纳米材料的合成与光致发光性能研究

发布时间：2018-04-14 16:39

  本文选题：氮化硼 + 纳米管　； 参考：《广西大学》2015年硕士论文

【摘要】：“低维材料”指的是一类在一个或多个维度处在纳米尺度范围内的新型材料,零维富勒烯、一维纳米管和二维纳米片就是这类材料的典型代表。与块体材料相比,低维材料由于存在量子尺寸效应和表面效应而展现出许多新的性能。氮化硼纳米材料经过近二十年的发展已经成为目前最具前景的无机纳米材料体系,低维氮化硼纳米材料具有极好的机械硬度、宽光学带隙、强紫外光发射、高热导率、卓越的热稳定性和化学惰性,在未来光电子、激光、场致发射、功能复合材料等应用上担当十分关键的角色。目前,氮化硼纳米管已通过多种合成方法成功制备,如电弧放电法、化学气相沉积法、固相法等,氮化硼纳米片也通过微机械处理法、化学溶剂剥离法、化学气相沉积法等被成功获得。但是这些方法或多或少的存在原料不安全、产量低、能耗大、形貌差等缺陷。本文在综述近年国内外对氮化硼纳米管和纳米片研究进展的基础上,采用工艺条件简单高效的固相反应法成功合成出高产量高纯度的氮化硼纳米管,并首次成功合成出由大量氮化硼纳米片组装而成的微米线,这是一种从未被报道的新型氮化硼微纳米结构。本文选用无定形硼粉为硼源、六水合氯化铁为催化剂、氨气为氮源,按催化剂与硼源摩尔比为0.05：1混合原料,在1200℃下与50 mL·min-1的流动氨气发生氮化反应5 h,得到高产量高纯度的竹节状氮化硼纳米管和由氮化硼纳米片组装而成的微米线,纳米管和微米线的直径均匀,平均直径分别约为90nm和2μm,微米线上的纳米片厚度低于20nm。其中,氯化铁甚少被报道用于催化氮化硼纳米管生长,在本实验中它不仅作为催化剂,更是反应历程中十分关键的反应物,能将固态硼源转化为中间态含硼气体。同时本文还研究了不同工艺条件对产物的影响,如反应温度、反应气氛、催化剂用量和种类、反应时间等。结果表明,中间产物气态硼源、催化剂小液滴和还原性气氛是影响氮化硼纳米管和微米线生长的关键条件。反应温度偏低、催化剂用量偏少、催化剂种类不同都会引起气态硼源和催化剂熔融小液滴的产量偏低,导致纳米管产量下降,微米线直径变小;不同还原性气氛中氢含量的多寡直接决定纳米管能否生长；反应时间过短会导致反应不完全,进而产物产量降低。综合各项表征数据结果,氮化硼纳米管的生长机制可归结为气-液-固和固-液-固的混合生长模型；氮化硼微米线初期生长是以纳米管为生长基体,在其上以气-固生长模型不断沉积大量纳米片,最终形成由纳米片组装而成的微米线。产物的光致发光(PL)性能研究表明,氮化硼纳米管和微米线分别在354m和357nm波长处出现强的发光峰。两种产物的PL曲线对比显示,微米线具有远远高于纳米管的紫外发光强度,显示出极其优异的紫外发光性能,结合其微纳米结构特性,在光电纳米器件中具有潜在的应用前景。
[Abstract]:"Low-dimensional material" refers to a new class of materials with one or more dimensions in the nanoscale range. Zero dimensional fullerenes, one-dimensional nanotubes and two-dimensional nanochips are typical examples of such materials.Compared with bulk materials, low dimensional materials exhibit many new properties due to the existence of quantum size effect and surface effect.After nearly 20 years of development, boron nitride nanomaterials have become the most promising inorganic nanomaterials. Low dimensional boron nitride nanomaterials have excellent mechanical hardness, wide optical band gap, strong ultraviolet light emission and high thermal conductivity.Excellent thermal stability and chemical inertia play a key role in the future applications of photoelectron, laser, field emission, functional composites and so on.At present, boron nitride nanotubes have been successfully prepared by a variety of synthetic methods, such as arc discharge, chemical vapor deposition, solid phase method, etc.Chemical vapor deposition was successfully obtained.However, these methods are more or less unsafe raw materials, low production, large energy consumption, poor morphology and other defects.On the basis of a review of recent progress in the research of boron nitride nanotubes and nanoparticles at home and abroad, boron nitride nanotubes with high yield and high purity were successfully synthesized by solid state reaction with simple and efficient process conditions.For the first time, a large number of boron nitride nanowires have been successfully synthesized, which is a new type of boron nitride microstructures that have never been reported.In this paper, amorphous boron powder is used as boron source, ferric chloride hexahydrate as catalyst, ammonia as nitrogen source, and the molar ratio of catalyst to boron source is 0.05: 1.At 1200 鈩，

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