外文翻译对用高温高压连续流微反应合成磷化铟纳米晶体的研究.doc

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1、华中科技大学文华学院毕业设计（论文）外文文献翻译（本科学生用） 题目: 对用高温高压连续流微反应合成磷化铟晶体的研究学 生 姓 名：饶龙 学号：080110021117学 部 （系）:信息科学与技术学部专 业 年 级: 电子科学与技术2班指 导 教 师：慎晓丽 职称或学位：讲师2012 年2月 27日 外文文献翻译（译成中文1000字左右）：【主要阅读文献不少于5篇，译文后附注文献信息，包括：作者、书名（或论文题目）、出 版 社（或刊物名称）、出版时间（或刊号）、页码。提供所译外文资料附件（印刷类含封面、封底、目录、翻译部分的复印件等，网站类的请附网址及原文】Investigation of

2、Indium Phosphide Nanocrystal Synthesis Using a High-Temperature and High-Pressure Continuous Flow Microreactor Jinyoung Baek, Peter M. Allen, Moungi G. Bawendi,* and Klavs F. Jensen Indium phosphide (InP) nanocrystals1are of significant interest for use in optoelectronic devices, specifically as a r

3、eplacement for CdSe nanocrystals in commercial applications. However, the current mechanistic understanding and synthetic procedures for InP nanocrystals has not yet reached the same level as for CdSe nanocrystal synthesis.2 Using a truly continuous three-stage microfluidic reactor to precisely tune

4、 reaction conditions in the mixing, aging, and sequential growth regimes, our study described here builds on previous InP nanocrystal synthetic3 and mechanistic work4 to probe the significant experimental parameters involved in InP nanocrystal syntheses. We find that the growth of InP nanocrystals i

5、s dominated by the aging regime, which isconsistent with a model of InP nanocrystal growth where nanocrystal growth is dominated by nonmolecular processes such as coalescence from nonmolecular InP species and interparticle ripening processes.4 The InP growth model is in contrast to the molecular-bas

6、ed growth of nanocrystals as observed in CdSe and PbSe nanocrystals.2af We observe that the size of InP nanocrystals is predominantly dependent on the concentration of free fatty acid in solution and the aging temperature. Other experimental parameters such as injection temperature and particle conc

7、entration do not appear to significantly affect InP nanocrystal size or size distributions. In addition, we probe the ability to grow larger InP nano-crystals through the sequential injection of precursors in the third stage of the microfluidic reactor. The use of high temperatures and high pressure

8、s in a continuous microfluidic system allows for a wide selection of solvents, precursors, and ligand systems, providing a vastly increased parameter space to explore synthetic conditions.The utilization of low-molecular-weight solvents at high pressures offers supercritical conditions tunable from

9、liquid to gas like providing high diffusion rates, improved mixing,6 and the ability to solubilize various compounds inaccessible by solvents employed in traditional nanocrystal syntheses.2b,c, 3, 7 The use of a supercritical solvent in a microfluidic reactor results in narrower residence time distr

10、ibutions, producing homogeneous reaction conditions ideal for nano-crystal synthesis.8 Microfluidic systems allow precise control over reaction conditions and reproducibility9 as a result of rigorous control of heat and mass transfer.10 In addition, themicrofluidic system can be utilized for fast sc

11、reening of reaction parameters with in situ reaction monitoring.11 Figure 1 illustrates our truly continuous three-stage sili-con-based microfluidic system consisting of mixing, aging, and sequential injection stages operating at a pressure of 65 bar, without incorporating any manual batch manipulat

12、ion between synthesis steps.2h We have separated each stage in order to independently probe mixing and aging processes. The first two stages of the reactor were utilized for the systematic study of InP nanocrystal formation (Figure 1 a,b). The mixing reactor was maintained at a uniform temperature t

13、o investigate the effect of different mixing temperatures. Alternatively, the first reaction stage can be heated to create a temperature gradient in order to rapidly obtain highly crystalline InP nanocrystals with relatively narrow size distributions (see Figure S1 in the Supporting Information,). T

14、he second (aging) stage of the reactor was operated at temperatures ranging from 200340 8C to study the effect of aging temperature. In the third stage of the system, a sequential injection reactor (Figure 1 c) was used to supply more molecular precursors for the further growth of InP nanocrystals.

15、In the case of most InP nanocrystal syntheses, both the aging and sequential growth reactors were maintained at 320 8C to utilize supercritical octane (Tc = 296.17 8C and Pc = 2.50 m Pa). Octane was selected as the solvent in order to provide excellent mixing, fast diffusivity, and sufficient densit

16、y for the solubilization of all reagents. 对用高温高压连续流微反应合成磷化铟纳米晶体的研究 Jinyoung Baek,彼得m艾伦,Moungi g . Bawendi、*和Klavs f詹森 磷化铟(InP)纳米晶1用于光电设备具有的重大价值,特别是在商业应用中作为一个硫化锌奈的替代品。然而，就硫化锌纳米晶体的合成来说，当前对InP纳米结晶机械的理解和合成程序尚未达到相同的水平。使用一个真正的连续三阶段的微流控反应堆来精确协调混合、老化和连续增长状态的反应条件,我们这里描述的研究建立在之前的铟的纳米晶体合成和机械的工作之上来探测重要的实验参数包含In

17、P纳米晶体的合成。我们发现的增长主要来自InP纳米晶体老化的状态,这是用一种模型一致InP纳米晶体增长,主要是无分子状态组成的纳米晶体生长过程,如聚结从无分子状态 InP物种和颗粒成熟过程。InP增长模式相比之下以分子为基础的增长和硫化锌奈的观测和硒化铅纳米晶体。我们观察到纳米晶体的大小主要取决于铟浓度溶液中游离脂肪酸和老化温度。其他实验参数如注入温度和粒子浓度似乎没有明显影响磷化铟纳米晶体大小或粒径分布。此外,我们探测生长能力更大的非晶 InP通过顺序注射进下一阶段的前身的微流控反应堆。利用高温和高压连续微流体系统允许用一种更广泛的选择溶剂,前兆,和配体系统,提供一个大大提高了参数空间探索的

18、合成条件。利用高压低分子量溶剂提供了超临界条件下可调从液体到液状物,提供高扩散率,改善混合,并能够进入溶剂溶解各种采用传统方法合成的化合物纳米晶体。使用超临界流体萃取反应堆结果在窄停留时间分布、生产同质的反应条件对合成晶态的理想。微流体系统允许精确控制反应条件和再现性由于严格控制的传热传质。此外,微流体系统能够被用于快速筛查的反应参数与原位反应监测。图1说明了我们真正连续三阶段微流体系统组成的混合、老化、以及顺序注射阶段操作压力为65巴.图一：三阶段的高温高压微流系统 a)混合阶段 b)老化阶段 c)通过六个额外的注入管道的顺序注入的微反应。管道的宽度和深度范围为80到400微米之间。顺序注射

19、的微反应包括伴随高流阻的压降区，来获得均匀分布的注射,以防止任何回流。 没有将任何人工合成步骤之间的批处理操作。2 h我们将每个阶段以独立调查的混合和衰老的过程。前两个阶段的反应堆被用作系统研究纳米晶体形成的铟(图1 a,b)。混合反应器的温度维持在恒温下用来调节不同温度混合的影响。另外，第一反应阶段可以加热到创建一个温度梯度以相对较窄的粒径分布来迅速获取高度结晶InP奈(参见图S1的支持信息)。第二个(老化)阶段的反应堆操作温度从200 - 340 C用来研究老化温度的作用。在第三阶段的系统,连续的注入反应堆(图1 c)被用来供给更多的分子使InP纳米晶体得到进一步的增加。就大多数InP合成纳米晶体来说,利用超临界辛烷(Tc = 296.17 8 C和Pc = 2.50 m Pa)无论是老化和连续增长反应堆被维持在320 C。辛烷被选为溶剂是为了提供更好的混合、快速扩散系数,以及足够的密度,，使所有的试剂得到溶解。指导教师审阅意见：指导教师：2012年 3月12日