Yu Shi Yong, Jing Hui, Cao Zhen, Su Hai Quan
J Nanosci Nanotechnol. 2014 May;14(5):3299-304. doi: 10.1166/jnn.2014.7990.
The Schiff base complexes modified ZnO quantum dots (ZnO-SBC QDs) are successfully synthesized via the reflux and chemical co-precipitation route. For control experiments, we also synthesized the ZnO QDs and amino-modified ZnO QDs (ZnO-NH2 QDs). The structures and morphologies of the samples were characterized via X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), FTIR spectroscopy (IR), Fluorescence Spectrometer (FL) and so on. The XRD pattern shows that the three types of QDs possess hexagonal wurtzite structures. The TEM investigation reveals that the as-prepared products have hexagonal morphologies. The plane fringe with 0.26 nm crystalline plane spacing of three types of quantum dots is assigned to the ZnO {002} planes via HR-TEM, which match with the lattice parameter of the hexagonal wurtzite structure of ZnO and also coincide with the data obtained by XRD. By analyzing the fluorescence emission and excitation spectra of ZnO QDs, ZnO-NH2 QDs, ZnO-SBC QDs and Schiff base complexes, we find that the ZnO-SBC QDs still have a perfect fluorescence emission which makes it interesting candidates for luminescence applications such as biochemical sensors and fluorescent labels to mark the cells and DNA. This novel ZnO-SBC QDs under UV irradiation is capable of generating reactive oxygen species by UV irradiation and may be used for the photodynamic therapy. The surface modification with Schiff base complexes makes it difficult to release Zn2+, therefore the toxicity is much more controllable.
通过回流和化学共沉淀法成功合成了席夫碱配合物修饰的氧化锌量子点（ZnO-SBC QDs）。作为对照实验，我们还合成了氧化锌量子点和氨基修饰的氧化锌量子点（ZnO-NH2 QDs）。通过X射线粉末衍射（XRD）、透射电子显微镜（TEM）、高分辨率透射电子显微镜（HR-TEM）、傅里叶变换红外光谱（FTIR）、荧光光谱仪（FL）等对样品的结构和形貌进行了表征。XRD图谱表明，这三种类型的量子点均具有六方纤锌矿结构。TEM研究表明，所制备的产物具有六边形形貌。通过HR-TEM将三种类型量子点的晶面间距为0.26 nm的平面条纹归属于ZnO {002}平面，这与ZnO六方纤锌矿结构的晶格参数相匹配，也与XRD获得的数据一致。通过分析ZnO QDs、ZnO-NH2 QDs、ZnO-SBC QDs和席夫碱配合物的荧光发射光谱和激发光谱，我们发现ZnO-SBC QDs仍然具有完美的荧光发射，这使其成为发光应用（如生化传感器和用于标记细胞和DNA的荧光标记）的有趣候选物。这种新型的ZnO-SBC QDs在紫外光照射下能够通过紫外光照射产生活性氧，可用于光动力治疗。席夫碱配合物的表面修饰使得Zn2+难以释放，因此毒性更可控。
