Design, Synthesis And Properties Of Novel Organic Luminescent Materials Containing Nitrogen Hetero-cycles

Organic molecules have been studied extensively not only for nonlinear optical materials but also for other luminescent materials. Over the past decades, extensive research has been conducted to develop organic materials with large two-photon absorption (TPA) cross sections because of their potential applications in two-photon fluorescence excitation microscopy, three dimensional optical data storage, optical power limiting and photodynamic therapy. But these applications depend on molecules with large two-photon absorption (TPA) cross-sections (a). However, the lack of materials with large two-photon cross sections restricts the development of these applications. According to the literatures, we reported some Ï€-conjugated multi-carbazole molecules or those which containing pyridine rings in this thesis. And the linear and nonlinear properties were also studied. The main works are stated as follows:1. Two Ï€-conjugated multicarbazole derivatives have been synthesized and characterized by ¹H NMR and ¹³C NMR, which have good solubility and high fluorescence quantum yield (Φ). The linear absorption and one-photon induced fluorescence are experimentally studied. In different solvents, the maximum peaks of linear absorption hardly have any change, while the maximum peaks of fluorescence clearly show red-shift with increase of the polarity of solvents. Such phenomenon can be explained by Lippert-equation as reported in the references. The emission behaviors of dual fluorescence in less polar solvents and single in more polar solvents, and strongly solvent-polarity dependent emissions are interpreted. The two-photon absorption cross sections of the two compounds in DMF were estimated by two-photon-induced fluorescence method, which are 26.0 GM and 73.5 GM, respectively. 2. Using the solvent-free or an aqueous phase Aldol condensation and...