Fluorescence Recovery And Visual Sensing For Pyrophosphate And ATP Based On CdTe-Eu³⁺ System

Quantum dots indicates different optic and electronic properties from the other molecular because of its quantum confinement effect. And recently, it has been a focus to the scientist. In our work, we first synthesized TGA capped CdTe quantum dots with a tunable size, symmetry emission and highly quantum yield in aqueous medium.After adding Eu³⁺ ions into CdTe QDs, CdTe QDs would aggreate bacause of trivalent europium ions acting as chelating agents to the oppositely charged NCs. Then electronic coupling and exciton energy transfer would happen, which induced redshift in the emission spectra and fluorescence quenching of QDs.Later, when we added different concentrations of pyrophosphate(PPi) or ATP into CdTe-Eu³⁺ system, we found that QDs disaggreated with fluorescence intensity and wavelengh recovery, so a novel fluorescence-turn-on and visual sensor for pyrophosphate or ATP based on CdTe-Eu³⁺ system has been developed. This thesis consists of six chapters summarized in the following:In chapter 1, first we gave a review on the properties and applications of semiconductor nanoparticles, then we described the advantage of fluorescence recovery and visual detecting, Finally, a proposal of research was presented.In chapter 2, water-soluble CdTe quantum dots capped with TGA or MPA were synthesized according to the literature, and its quantum yield, luminescent property and crystalloid were characterized.In chapter 3, we used trivalent europium ions acting as chelating agents to the oppositely charged NCs, induced the aggreation of QDs with redshift in the emission spectra and fluorescence quenching.In chapter 4, the experiments showed that the original luminescence intensity and wavelength of QDs can gradually recover by the addition of PPi, due to the disintegration of the QDs clusters resulting from more intensive competition combine of phosphates with Eu (III) due to the disaggreation of QDs. Therefore, a novel fluorescence recovery and visual sensor for pyrophosphate based on CdTe CdTe-Eu³⁺ system has been developed in aqueous medium.In chapter 5, At the same time, a novel fluorescence recovery and visual sensor for ATP based on CdTe-Eu³⁺ system has also been established in aqueous medium.In chapter 6, traits and innovations of the thesis were summarized. An outlook of further research was given.