The Synthesis And Properties Of Optical Function Material Based On OPV Moiety

Two-photon excitation is the process that used two low-energy photons excitated molecule to high-energy excited states and the two-photons absorption rate or two-photons introduced fluorescence intensity is proportional to the square of excitation light intensity. These characteristics made two photons absorption materials have some potential applications, such as optical power limiting, two-photon laser scanning fluorescence imaging, photodynamic therapy, high-density optical data storage,3D micro-and nanofabrication. All the applications depend critically on the availability of materials with high TPA cross sections. The value of two-photons cross section is relate to molecular conjugation length, planarity of theπcenter, properties ofπcentral part, donor and acceptor strength and the Molecular dimension. Oligo(phenylene vinylene)s (OPV) derivatives were widely used as two-photons absorption material, electroluminescence material and solar cell material due to their good planarity structure, facile delocalizedπelectron and good fluorescent emission. Base on the characteristics of OPV, we designed and synthesized some OPV derivatives modified by some functional group (such as pyridine, pyridinium, triazine and long alkyl chains). These OPV derivatives have selfassemble property and could be used as two-photons absorption materials. Their structures were character by NMR and MALDI-TOF MS.The OPV pyridine derivative have good fluorescent property. The introduction of butoxyl to OPV skeleton could form push-pull electronic structure and significantly improve the quantum yield of compound. Compound PO have good fluorescence response to pH value and its detection range is pH=4-5.5.Based on the OPV pyridine derivative, we synthesized some OPV pyridinium derivatives by introduced long alkyl. Different anion introduced by anion exchange. The result of absorption and fluorescence spectra analysis shows that these compounds have strong intromolecular charge transfer property and show negative solvatochromism. The type of anion and the length of alkyl have no influence to the absorption peak and emission peak. But the type of anion could influence the Molar absorption coefficient and fluorescent intensity of the OPV pyridine.The study of the gelation property of the OPV pyridiniums shows that the type of anion and the length of have influent to the gelation ability of the OPV pyridiniums. From all the OPV pyridinium we obtained, POC16-Br and POC16-OH could gelate in different solution and the gelation ability of POC16-OH is much better than that of POC16-Br. The SEM images show that the aggregation morphology of POC16-Br xerogel revealed a flocculent network. And in the case of POC16-OH xerogel, the image revealed a network structure composed of intertwined fibers with the width of 200-300 nm. The study of 1H NMR and IR show that the noncovalent forces for their gel forces wereπ-πstacking and van der Waals interactions. POC16-OH have had better gelation ability is attribute to the hydrogen bonding between OH- in POC16-OH gelation process. Because of the hydrogen bonding in POC16-OH gel system, it's gel was acid sensitive.Two-photon laser induced fluorescence measurements have shown that the type of anion could influence the TPA cross section of the OPV pyridinium. In our study, OPVOH have a small TPA cross section (35 GM), while OPVBr have a large TPA cross section (904 GM). Furthermore, we found that the TPA cross-sections value of OPVBr is increased with the concentration increasing due to the enhancement of intramoleculeπ-πstacking interaction.Lastly, We obtain a series of OPV triazine derivatives with octupolar structure. Their linear optical properties were study by absorption and fluorescence spectra analysis. Two-photon laser induced fluorescence measurements shows that compound Q1,Q2 and Q3 have large TPA cross section and the TPA cross section increases with increasing donor and acceptor strength, conjugation length, and planarity of theπcenter. In order to made Q1,Q2 and Q3 used in aqueous solution, their fluorescent organic nanoparticles were prepared through a simple reprecipitation method. The size distribution of the nanoparticles was determined by scanning electron microscopy and dynamic lighter scattering analysis. Their nanoparticle had an average diameter of 150-200 nm. We studied the fluorescence spectra of Q1,Q2 and Q3 in the THF-water mixture with different water fractions. The results show that the fluorescence intensity decreased as the water volume fraction increased firstly and then fluorescence intensity increased when the nanoparticles formed in solution. When the water volume fraction is 80%, the nanoparticles have the strongest fluorescence intensity. Two-photon laser induced fluorescence measurements of the Q1 nanoparticles in THF-water mixture hen the water volume fraction is 80% shows that the TPA cross section of nanoparticles is bigger than that of monomer molecule.