Synthesis Of Aqueous CdTe QDs And Reliminary Study On Their Application In Near Infrared Fluorescence Field

Quantum dots (QDs) are semiconductor nanoparticles (NPs) with diameters in the range of 1-10 nm. QDs could provide broad excitation spectrum, narrow emission spectrum, tunable emission wavelength and neglectable optical bleach phenomenon etc., so they can be used as good materials for fluorescent labeling, and ideal bioconjugated fluorescent probes for bioanalysis. Because of QDs'unique optical and electronic properties,they have attracted great attention from scientists in many fields. In the first chapter, we described the basic knowledge and optical characters of QDs in section 1, synthesis routes and growth mechanism in section 2, characterization techniques in section 3, and recent progresses and applications to life science in section 4.In the second chapter, route for synthesizing high-quality CdTe QDs at room temperature and room pressure in aqueous solution is presented, and we also discussed the influencing factors by abundant experiments. By using hydrazine hydrate as the energy provider to actuate the growth of QDs, we synthesized high-quality CdTe QDs with controllable photoluminescence (PL) wavelength from 490 nm to 620 nm in a relative short time, without heating and microwave etc. As-prepared CdTe QDs were shown to have narrower full wave at half maximum (FWHM), higher photoluminescence quantum yields (PL QY), and symmetric fluorescent emission peak. The PL QY reaches 60% or above at room temperature without any post-preparative treatment. To our best knowledge, the simple experimental conditions, low cost and good repeatability, make it bacome one of the most successful methods which can directly prepare CdTe QDs in aqueous solution with high quality. In addition, it showed feasibility to synthesize CdTe QDs with near infrared fluorescence that make it be able to apply widely to biochemical analysis in the near future. In the third chapter, we discussed the feasibility to synthesize the near infrared fluorescence CdTe QDs based on the synthesis route presented in the second chapter. We optimizated the experiment conditions and prolonged the reaction time, after characterization and analysis, it was shown that this method was unable to prepare the near infrared fluorescence CdTe QDs.