| This dissertation is based on a large number of literature and lots of experimentdata, and mainly focuses on the design, synthesis, and character research of a series offluorescent systems, including quantum dots fluorescence, organic moleculefluorescence and inorganic metal complex fluorescence system. Every fluorescencesystem has its own unique characters. Based on these characters, they can be designedfor different functional fluorescence materials and devices. This dissertation is dividedinto six chapters.In chapter 1, this chapter introduces the review about the definition offluorescent materials, structure, characteristics and luminescence properties offluorescent materials including quantum dot system, organic molecule system, metalion system and the presentation of the synthesis of a variety of fluorescent materialswith unique character and research progress in this field.In chapter 2, this chapter presents a simple method to synthesis CdS quantumdots with a high quantum yield. In our work, by changing the traditional strategy, weapply polyethyleneimine with different molecular weight to modified CdS quantumdots, in order to enhance the quantum yield, which reaches about 95% close to 100%,and, successfully, developed a simple method to synthesis high quantum yieldquantum dots in aqueous solution.In chapter 3, we discovered that there was FRET between CdS QDs (λem=480nm) and acridine orange (λex=490 nm), meanwhile, to our surprise, CdS quenched thefluorescence of AO. And DNA enhanced fluorescent signals of the system of AO andCdS. The enhanced extents were in good proportion to DNA concentrations. Based onthis, a novel sensitive method was employed to determine DNA with good selectivityand sensitivity. The calibration curve was linear over 60-4000 ng mL-1. Thedetermination limit (3σ) was 4.39 ng mL-1. The method was applied to thedetermination of DNA in synthetic samples with satisfied results. The fluorescence ofAO is quenched by forming AO-CdS ground state complex. In chapter 4, we synthesized two fluorescent chemosensors using rhodamine as afluorephore and were able to alter their selectivity to Fe(Ⅲ) and Cr(Ⅲ) by tinystructure alteration of the recognition moiety. The selectivity of Rh1 and Rh2 wasswitched between Fe(Ⅲ) and Cr(Ⅲ) at neutral pH value (7.2) in 100% aqueoussolution, depending on their structures. Commonly coexistent metal ions, e.g. Cd2+,Co2+, Cu2+, Ni2+, Zn2+, Mg2+, Ba2+, Pb2+, Na+, and K+ displayed little interference toboth Rh1 and Rh2.In chapter 5, this chapter presents the design and synthesis of the schiff basefluorescent Zn2+ sensor CB1. And, in ethanol / water (9:1Ⅴ/Ⅴ) mixed solution, theabsorbance and fluorescence characters of the interaction of ligend CB1's and metalion were studied. Combined compared with similar structure ligand CB2 and CB3 andcomputational chemistry calculations, we obtained the interaction mechanism of CB1and Zn2+. The fluorescence intensity of CB1 is able to increase 65 times due to Zn2+addition with maximum absorption wavelength at 390 nm, maximum emissionwavelength at 493 nm.In chapter 6, this chapter presents the study and discussion of lanthanidecomplex's optical properties. The EuL complex forms a dual-core cage-like structurewith a relatively closed system. And the TbL complex forms a helical polymer chain, amore open structure. Due to the data of fluorescence lifetime and quantum yield, theenergy level between the ligand and Tb(Ⅲ) matches better than that between theligand and Eu(Ⅲ). Furtermore, Eu(Ⅲ) and Tb(Ⅲ) complex shows different responseto pH value.The fluorescence intensity of Tb(Ⅲ) complex changes with pH changing,displaying fluorescence switch phenomenom; Eu(Ⅲ) complex do not have such aproperty, under the same conditions, the fluorescence intensity of Eu(Ⅲ) complex istoo weak to detect.
|
PDF Full Text Request