制备水溶性CdS量子点的一种物理方法：飞秒激光烧蚀法

用Ti/sapphire飞秒激光系统产生的100fs、800nm激光对置于水中的CdS体相材料进行烧蚀,得到了水溶性CdS纳米粒子。这种纯物理过程保证了无污染的制备环境,从而保证了所合成材料的纯洁性。通过透射电子显微镜、紫外/可见/近红外吸收光谱、室温光致发光谱的方法对CdS量子点的形貌及其光学性质进行了表征。结果表明:利用飞秒激光烧蚀法所制备的CdS量子点可直接分散在水中而且具有粒径小、分布均匀的特点;同时具有较好的胶体稳定性,可在空气中稳定存放6个月以上。飞秒激光烧蚀法所制备的CdS量子点所具有的这些性质使其在生物标记领域引起极大的兴趣,而且也为纳米材料的制备提供了新的思路。

A Physical Method for Fabrication of Water-soluble CdS Nanoparticles:Femtosecond Laser Ablation

Water-soluble CdS nanoparticles have been prepared by femtosecond laser(100 fs,800 nm,FL)ablation of a bulk CdS target in water.Being performed in a controllable contamination-free environment,this method makes possible the production of nanomaterials without impurities.The morphology and the optical characteristics were studied through transmission electronic microscopic,UV-Vis optical absorption,and room temperature photoluminescence.The results indicated that the obtained water soluble CdS quantum dots fabricated by femtosecond laser ablation have small size and narrow size distribution.As well,these quantum dots were found to be exceptionally stable in air for at least 6 months.In addition,under the excitation of 300 nm,the photoluminescence of the CdS quantum dots ablated in water shows a band-edge emission peaked at 420 nm with FWHM of 62 nm.The above-mentioned characteristics make these CdS nanoparticles of great attraction for potential application in biological labeling.This work demonstrates that the FL ablation is a simple but effective method for preparation of high quality quantum dots.