CdS纳米粒子的自组装单分子膜制备研究

利用疏基乙酸与草酸的混合自组装单分子膜成功制备了粒径分布均匀的CdS纳米粒子，并用SEM，XRD，XPS，PL对样品进行了表征。SEM表明形成在自组装单分子膜表面上的CdS纳米粒子的平均粒径约为45nm。XPS表明在自组装单分子膜表面形成了CdS纳米粒子。PL谱表明CdS纳米粒子在675nm有一峰值波长，我们认为这一发光是由表面缺陷造成的。

Synthesis, Study of CdS Nanoparticles by Self-assembled Monolayer

In the past decade, preparation of nanoparticles whose sizes and size distribution can be well controlled has become an important subject in materials science fields. Many methods have been developed in preparation of semiconductor nanoparticles, such as Langmuir-Blodgett (LB) films, colloid-chemical, electrochemical, electrophoresis, thermolysis of organometallic compounds in solution, template and self-assembled monolayers etc. The self-assembled monolayer was reported by Sagtiv in 1983. Hereafter the method has attracted wide interesting due to its simple operation, easy preparation, and no need of complex instruments, but it meets great difficulties to obtain a desirable size distribution.A new method for preparation of nearly monodisperse CdS nanoparticles by self-assembled monolayers of mercaptoacetic acid and oxalic acid is reported. The mercaptoacetic acid plays an important role in the formation of the CdS nanoparticles. The preparation procedures were shown in Fig. 1. There include three major steps: First, preparing of self-assembled monolayers of mercaptoacetic acid and oxalic acid on aluminum substrate; Second, immersing the substrate into solution containing Cd2+ to exchange ions; Third, Cd2+ reaction with H2S gas to form CdS nanoparticles. In the formation process of the nanoparticles, CdS molecular formed at mercaptoacetic acid will play a role of nuclear center. The CdS nanoparticles were characterized by SEM, XRD, XPS and PL, respectively. SEM image indicates that the average size is about 45nm, which is well agreement with XRD result. Room temperature PL spectrum shows that CdS has a wide emission band in the range from 500 to 800nm about and the emission peak is at 675nm, which is attributed to surface defects.