Study On The Preparation And Application Of Fluorescent Quantum Dots

As a new biological probe, fluorescent semiconductor quantum dots have brought profound changes of research methods and means in the field of biomedicine. Compared with the conventional organic fluorescent dyes, fluorescent QDs have wide and continuous excitation spectra, narrow,symmetrical and controllable emission spectra, larger Stokes shift and absorption coefficient, higher fluorescence quantum yields and photo-stability, have spatial compatibility, can be used for multi-photon fluorescence microscopy imaging and so on. These unique characteristics make QDs have the potential to replace the traditional organic fluorescent dyes as a novel biological fluorescent probe.This thesis mainly focused on the synthesis of high fluorescent properties of QDs, and also studied their optical properties and their application in the analysis area. The main results are described as follows:1. Single nuclear CdSe QDs were synthesized. The influence factors on the fluorescent properties of CdSe QDs, such as reaction time, reaction temperature, annealing time and the initial ratio of Cd and Se were investigated, and optimized the synthesis technology of CdSe QDs by orthometric experiment.2. Based on the single nuclear CdSe QDs, CdSe/ZnS shell-core QDs coated with ZnS materials were prepared. It's shown that the fluorescence quantum yields and intensity increased significantly when coated with ZnS.3. Water-soluble CdTe QDs were synthesized in aqueous solution with thioglycolic acid as the stabilizer by one step. Compared with other types of water-soluble QDs, CdTe QDs have better fluorescent properties, stronger photo-stability. Water-phase synthesis has low cost, easy to operate, and the synthesized QDs can be directly applied in biomedical fields.4. A new approach was studied on the determination of silver ions with water-soluble CdTe QDs as fluorescent probe based on the fluorescence quenching method, and discussed the fluorescence quenching mechanism. This method is simple, rapid, selective, high sensitive, low detection limit and is a new detection method.