1、 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 2 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
2、译部分的复印件等，网站类的请附网址及原文 】 Investigation of 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 op
3、toelectronic devices, specifically as a replacement 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-sta
4、ge microfluidic reactor to precisely tune 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 f
5、ind that the growth of InP nanocrystals is dominated by the aging regime, which is consistent 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
6、 model is in contrast to the molecular-based 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
7、as injection temperature and particle concentration 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
8、use of high temperatures and high pressures 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 off
9、ers supercritical conditions tunable from 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 reacto
10、r results in narrower residence time distributions, 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, themicro
11、fluidic system can be utilized for fast screening 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, 3 with
12、out incorporating any manual batch manipulation 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 react
13、or was maintained at a uniform temperature to 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
14、Figure S1 in the Supporting Information,). The second (aging) stage of the reactor was operated at temperatures ranging from 200 340 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
15、 for the further growth of InP nanocrystals. 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 density for the solubilization of all reagents.
