ZnSe量子点水相合成过程的原位研究
In Situ Studies on Aqueous Synthesis of ZnSe Quantum Dots

DOI: 10.12677/CMP.2015.42009, PP. 77-84

Keywords: 量子点，水相合成，原位光谱，XAFS
Quantum Dot, Aqueous Synthesis, In Situ Spectroscopy, XAFS

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Abstract:

本文运用原位吸收光谱和荧光光谱技术研究了谷胱甘肽(GSH)包覆的ZnSe量子点在水相合成过程中光学性质的变化，结合X射线衍射(XRD)和原位X射线吸收精细结构谱(XAFS)的结果，探讨了该过程中量子点的结构演变。结果表明，ZnSe量子点的水相合成过程可分为三个阶段：快速生长→表面重构→晶格弛豫。最初的20分钟为快速生长期，ZnSe量子点的生长十分迅速，表面有很多缺陷；20至40分钟为表面重构期，ZnSe量子点的生长放缓，表面缺陷逐渐减少，荧光量子产率(PLQY)随之升高；40分钟后为晶格弛豫期，Se-Zn键的键长略有增加，ZnSe量子点的尺寸增加缓慢。
In situ absorption and PL spectroscopy were employed to investigate the luminescent properties of GSH capped ZnSe quantum dots (QD) obtained from aqueous synthesis. Combined with the re-sults of X-ray diffraction (XRD) and in situ X-ray absorption fine spectroscopy (XAFS), the struc-tural evolution of the QD during the growth process was probed. Detailed analysis reveals that, the growth stage of ZnSe QD could be divided into three stages: fast growth → surface reconstruction → lattice relaxation. In the initial 20 min, ZnSe QD grows quite fast with massive surface defects; during 20 - 40 min, the surface of ZnSe QD undergoes reconstruction, which means the growth rate slows down, and the surface defects reduce, accompanying with the increase of PL quantum yield. After 40 min, ZnSe QD goes through lattice relaxation, the bond length of Se-Zn slightly increases and the size of QD increases slowly.

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