Studyonopticalproperties Andbiologicalstabilityofthe Cu₂S Quantum Dots

The synthesis and application of Quantum dots(QDs) have become the frontier direction in current research. Due to their better physical and chemical properties, they have huge potential applications in optical device. With the development of quantum dots, that make possible in the application of biological field. However, the toxicity of the traditional quantum dots with Cd that have been made so far has remained a major obstacle to the biological use of QDs. So people focus on the research of the Cd-free QDs, which with lower toxicity than the Cd QDs.In this thesis, I study the synthesis of Cu2 S QDs in organic phase firstly, then I applied the phospholipid to modify the Cu2 S QDs, and study the optical and biological properties of the QDs, which before and after modified. First, I introduced the characteristic, applications and the technical security of the quantum dots. Analyze strong absorption characteristics and optical stability of QDs from the aspects of nonlinear optical effects in theoretically. And explain the reason of generate the strong absorption, the basic theories of nonlinear absorption and quantum confinement effect. Then, we present the synthesis method of Cu2 S QDs and phospholipid modified Cu2 S QDs, and did the physical characteristic of the before and after modification the Cu2 S QDs. At last, I studied the strong absorption characteristics and the optical stability of the phospholipid modified Cu2 S QDs, the results show that the Cu2 S have the property of strong absorption, and absorption rates are above 80%. At the same time, it also has good optical stability, under different conditions, its particle size changed little under the light excitation in 12 h.The cells toxicity experimental study shows, the toxicity of Cu2 S QDs is lower than the CdSe QDs. The results show the Cu2 S QDs have low toxicity and biocompatibility, which indicating Cu2 S QDs are more suitable for biological detection applications.