Study On Structure Design, Biochemistry Analysis And Photoelectric Conversion Of Quantum Dots

Quantum dots materials show great potential in many applications such as lumi-nescence devices, bio-imaging fluorophores, biochemical analysis and solar cells dueto their outstanding optical and electronical properties. Quantum dots are used asfluorescent probes due to their surface modifications. With the development of nano-technology, surface modifications and performance improvement of Quantum dotshave become a core objective of modern research in biochemical analysis. For thevirtue of quantum confinement effect and multiple exciton generation of quantum dots,the reasearch of quantum dots sensitized solar cells have gained great interests inrecent years.In this thesis, water-soluble CdTe quantum dots were synthesized and applied inthe field of biochemical analysis, and CdS or CdSe nanoparticles were prepared andused in the field of solar cells.L-cysteine functionalized CdTe quantum dots with excellent fluorescenceproperties were successfully prepared by simple water-phase synthesis method. Basedon the fluorescence quenching of quantum dots, the fluorescence method for thedetermination of chloramphenicol was proposed using quantum dots as a fluorescentprobe. The developed method was used for the determination of chloramphenicol inthe commercial chloramphenicol tablets, and the results were consistent with theclaimed value.Mercapto propionic acid functionalized CdTe quantum dots and L-cysteine andmercapto propionic acid functionalized CdTe quantum dots were synthesized bysimple water-phase synthesis method. Based on fluorescence quenching of quantumdots, the fluorescence methods for the detection of tetracycline and malachite greenwere developed by synchronous fluorescence method. The proposed methods wereused to determinate tetracycline and malachite green in the samples, and the resultswere consistent with the claimed value and the adding value.Thioglycolic acid functionalized CdTe/CdSe core-shell quantum dots wereprepared by water-phase synthesis method. Based on the fluorescence enhancement ofquantum dots, the fluorescence methods for the determination of kanamycin andstreptomycin were proposed with quantum dots as fluorescent probes. The proposedmethods were used for the determination of kanamycin and streptomycin in thesamples, and the results by the presented method were in accordance with those of HPLC method.CoO nanowire arrays were grown on the FTO substrates by chemical bath depo-sition method. Then, CdS or CdSe nanoparticles was electrodeposited on the CoOnanowire arrays, and CdS/CoO or CdSe/CoO nano-heterojunction was formed. TheCdS/CoO or CdSe/CoO nano-heterojunctions was used as the photocathode forquantum dot sensitized solar cells, and the photoelectric conversion efficiency of0.102%or0.015%was achieved.In addition, the possible reaction mechanisms of quantum dots and biochemicalmedicines, and the mechanisms of cathodic photocurrent generation in CdS/CoO andCdSe/CoO nano-heterojunction were discussed, which set a good foundation forapplication research in biochemical analysis and quantum dot sensitized solar cells.