生物大分子杂化处理的CdSe/ZnS核/壳量子点多层膜的超快三阶非线性研究  

Third-order nonlinear optical properties of hybrid filmsof biopolymer-CdSe/ZnS core-shell quantum dots

作　　者：丁沙[1] 王小慧[2] 杜予民[2] 王取泉[1] 

机构地区：[1]武汉大学物理系,武汉430072 [2]武汉大学资源与环境科学学院,武汉430072

出　　处：《物理学报》2006年第2期753-757,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10474075)资助的课题.~~

摘　　要：利用静电自组装技术,以生物大分子材料壳聚糖杂化处理具有稳定结构的CdSe/ZnS核/壳量子点,形成复合多层薄膜.与薄膜的吸收谱线比较,在375nm飞秒激光激发下测量的量子点的光致发光谱存在Stokes位移.采用Z扫描技术,利用790nm飞秒激光研究了其三阶非线性吸收和折射特性,发现饱和吸收信号来自CdSe/ZnS量子点,而自聚焦的折射信号则部分来自壳聚糖.测出多层膜的三阶非线性系数分别是β=6·5×10^(-6)cm/W,n2=1·5×10^(-10)cm2/W.Biopolymer-CdSe/ZnS core-shell quantum dot hybrid films were prepared using self-assembly technique. Compared with the absorbance spectrum, the photoluminescence excited by laser with λ= 395nm has Stokes shift. The third-order nonlinear optical properties of biopolymer-CdSe/ZnS film were studied by Z-scan setup with femtosecond laser at 790nm. It is found that the nonlinear absorptive signal partially originates from Cde/ZnS quantum dots while the nonlinear refractive signal partially originates from biopolymer chitosan. The magnitudes of them are measured to be ,β = 6.5 × 10^-6cm/W and n2 = 1.5 ×10^-10cm^2/W, respectively.

关 键 词：CdSe/ZnS量子点 非线性性能 光致发光谱 

分 类 号：O611.3[理学—无机化学]