MAA修饰ZnO量子点及其发光特性

以ZnAc2·2H2O为原料,在乙醇中通过70℃回流4h,得到ZnO前驱物,与LiOH·H2O反应,制备出ZnO.采用巯基乙酸(mercaptoacetic acid,MAA)对所合成的ZnO进行表面修饰,修饰后的产物经SEM和XRD表征,证明获得了物相单一、近似球状、粒径为4.6nm的ZnO量子点.借助紫外-可见和荧光分析,研究了MAA对该量子点的修饰效果,探讨了设置条件下ZnO的发光机理和性质.发现该实验体系之所以产生荧光表面缺陷发射峰消失和激子发射峰明显增加的光学现象,是因为MAA有效地覆盖了ZnO的表面缺陷,并稳定包裹住ZnO粒子.同时还研究了MAA加量、温度、电解质对修饰产物发光性能的影响,发现经MAA修饰后的ZnO量子点具有较强的荧光发光性能、良好的长期陈放稳定性,以及一定的抗电解质影响能力.研究结果对ZnO量子点应用于生物分析具有重要参考价值.

MAA-modified ZnO quantum dots and their luminescence properties

The precursor of ZnO has been prepared by refluxing in ethanol at 70 ℃ for 4 h using ZnAc2·H2O as an initial agent.Then ZnO has been prepared from the reaction of LiOH·H2O and the precursor.ZnO was modified by mercaptoacetic acid（MAA） and detected by SEM and XRD.These ZnO particles have single phase,a sphere-like shape and the size of 4.6 nm.The modified effectivity of MAA for the quantum dots（QDs） has been investigated with UV-visible and fluorescence analysis,and the mechanism and property of ZnO light emitting have been discussed under given conditions.The reasons why the fluorescent emission peak of surface defects disappeares and the exciton emission peak increases are that MAA effectively covers the surface defects of ZnO and stably coats ZnO particles.The effect of the added amount of MAA,temperature and electrolyte on light-emitting properties of modified products has also been studied.The result shows that the modified ZnO QDs have good fluorescence properties,stability and suitable capability of resisting electrolyte.These results are significant for biological analysis.