水溶性ZnS∶Ni量子点的合成及荧光性质

Synthesis and Fluorescence Properties of Water-Soluble ZnS∶Ni Quantum Dots

以L-半胱氨酸为修饰剂,采用化学共沉淀法在水溶液中合成了ZnS∶Ni量子点。通过X-射线粉末衍射(XRD)、透射电镜(TEM)、红外光谱(IR)和荧光光谱(PL)对量子点的结构、组成、形貌及光谱性质进行表征。结果表明:ZnS∶Ni量子点为立方闪锌矿结构,颗粒呈球形,平均尺寸约为2.9 nm,分散性良好;随着Ni2+掺杂浓度的增加,ZnS∶Ni量子点的荧光发射强度先增强后减弱,当Ni2+掺杂浓度为0.7%时,发射强度达到最大。经室内自然光照后,ZnS∶Ni量子点的荧光量子产率可达15.4%。修饰在量子点表面的L-半胱氨酸使该量子点具有良好的水溶性、生物相容性和生物大分子可偶联性。

ZnS： Ni quantum dots were synthesized in aqueous medium by chemical co-precipitation method using L-cysteine as a modifier. The structure, morphology, component and spectrum properties of the quantum dots were characterized by XRD, TEM, IR and PL. The results show that ZnS： Ni quantum dots are spherical with diameter around 2.9 nm, own good monodispersity and belong to the cubic blende structure. The PL intensity of ZnS： Ni quantum dots exhibits a gradual enhance followed by a steady decline with increasing Ni2~ content, attaining its maximum when the doping content of Ni2＋ was 0.7%. After illumination with indoor natural light, the fluorescent quantum yield of ZnS： Ni quantum dots can reach 15.4%. The L-cysteine modified on the surface of ZnS： Ni quantum dots renders the quantum dots water-soluble, biocompatible and the ability to couple with biological macromolecules.