Study Of The Photophysical Properties Of BODIPY Derivatives And Rhodamine

BODIPY and Rhodamine are important organic fluorescence material. The design and synthesis of new compounds and the study of their properties are the current main research areas. In this thesis, several modified meso-benzene ring of BODIPY were designed and synthesized. We measured and discuss its photophysics. We also prepared the But-RB nanoparticles by reprecipitation method and measured its photophysical properties, and its properties at different aggregation state were compared.In the second chapter, we conducted characterization for several BODIPYs, including IR, UV-vis absorption spectra, fluorescence spectra, fluorescence lifetime fluorescence quantum yield and singlet oxygen. The carboxyl group in the 2’-position of meso-benzene ring could restrict the free rotation of the benzene. While the stronger the substituents on other position draw electron,the bigger the absorption and fluorescence spectra red shift. The quantum yield was affected by the substituent effect greatly, and its lifetime were mostly double esponential fitting. The singlet oxygen yield of BODIPYs in ethanol were low, except(Br)4-PBDP-COOH and NBDP-COOH. The yield was greatly affected by the polarity of the solvent.In the third chapter, Nanoscaled rhodamine(NSR) dyes were prepared by reprecipitation method and characterized by TEM and laser diffraction analysis. The optical properties of nano wired rhodamine dyes were studied by UV-vis absorption and steady state/time resolved fluorescence. The size of NSR dyes is tunable by varying the concentration of rhodamine or surfactant additive. Compared to corresponding molecular rhodamine, the fluorescence lifetime of NSR dyes is 4.5-fold longer, while the emission maximum can be 150 nm longer. Although the increase in size of nanoscaled NSR dyes leads to large red shifts in optical absorption and fluorescence spectra, it does not affect the fluorescence quantum yield and lifetime. On the other hand, the presence of a surfactant(sodium dodecyl benzene sulfonate) not only causes the increase in fluorescence quantum yield, but also greatly extends the fluorescence lifetime of NSR dyes from 1.51 ns to 7.07 ns.