自组装壳聚糖/CdSe-ZnS核壳量子点多层膜的制备及其三阶光学非线性

Preparation and third-order optical nonlinearity of self-assembled chitosan/CdSe-ZnS core-shell quantum dots multilayer films.

作者信息

Wang Xiaohui, Du Yumin, Ding Sha, Wang Ququan, Xiong Guiguang, Xie Min, Shen Xincheng, Pang Daiwen

机构信息

School of Resource and Environmental Science, Department of Physics and Center for Nanoscience & Nanotechnology Research, and College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.

出版信息

J Phys Chem B. 2006 Feb 2;110(4):1566-70. doi: 10.1021/jp055916c.

DOI:10.1021/jp055916c

PMID:16471716

Abstract

The self-assembled chitosan CdSe quantum dots (QDs) and chitosan CdSe-ZnS core-shell QDs films have been prepared by using layer-by-layer electrostatic technique. The well-ordered nanostructure and the layer-by-layer deposition of the QDs are revealed by AFM and exciton absorption spectra, respectively. The optical nonlinearity of the composite films were studied by using Z-scan technique with femtosecond pulses at the wavelength of 790 nm, the value of third-order susceptibility of core-shell QDs are measured to be about 1.1 x 10(-8) esu, which is about 200% larger than that of CdSe QDs of 5.3 x 10(-9) esu. This has potential applications in all-optical switches in optical information processing.

摘要

通过层层静电技术制备了自组装壳聚糖CdSe量子点（QDs）和壳聚糖CdSe-ZnS核壳量子点薄膜。原子力显微镜（AFM）和激子吸收光谱分别揭示了量子点有序的纳米结构和层层沉积情况。利用Z扫描技术在790nm波长的飞秒脉冲下研究了复合薄膜的光学非线性，测得核壳量子点的三阶极化率约为1.1×10^(-8) esu，比CdSe量子点的5.3×10^(-9) esu大200%左右。这在光信息处理的全光开关方面具有潜在应用。