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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.
Using electrostatic self-assembly technique, CdSe / ZnS core / shell quantum dots with a stable structure were hybridized with chitosan as a biological macromolecule material to form a composite multi-layer thin film. Compared with the absorption spectrum of the thin film, The Stokes shift was observed in the photoluminescence spectrum of the quantum dots measured by the X-ray diffraction method.The third-order nonlinear absorption and refraction properties of the QDs were investigated by Z-scan technique and found that the saturated absorption signal was from the CdSe / ZnS QDs, Of the refraction signal is partly from chitosan.The third-order nonlinear coefficients of the multi-layer films were measured respectively as follows: β = 6 · 5 × 10 -6 cm / W, n 2 = 1.5 × 10 -10 ) cm2 / W.