Synthesis And Aggregation-induced Emission Of Triarylamine Derivatives With Two-Photon Absorption

In the aspect of biophotonic application, organic electroluminescent materials with large two-photon absorption (TPA) and aggregation-induced emission (AIE) have remarkable practical value. In this dissertation, three new classes of triarylamine-based derivatives with AIE or TPA have been designed and synthesized, and their one- and two-photon absorption (2PA) properties and optical limiting properties have been investigated.The main contents were generalized as follows:In Chapter 1, the design strategy of the thesis was presented after the recent progress of the materials with aggregation-induced emission or two-photon absorption is reviewed.In Chapter 2, a new series of linear and multi-branched bithiazole-based dyes (BTZ-Ⅰ～Ⅳ) possessing terminal triphenylamine group were synthesized and characterized, and their one-and two-photon absorption properties have been investigated. These new compounds exhibited large two-photon absorption cross sections (σ), in which theσdata measured by the open aperture Z-scan technique were determined to be 173,429,1132 and 1665 GM for BTZ-Ⅰ, BTZ-Ⅱ, BTZ-Ⅲand BTZ-Ⅳ, respectively. A considerable increase in the value of 2PA cross section was obtained when triple bonds were introduced or the dimensionality and chromophore density increased.In Chapter 3, the syntemic photoelectric properties of TAPA(a-b) have been investigated, including steady state spectra, time-resolved fluorescence spectra, aggregation-induced emission and two-photon absorption property. With the increase of solvent polarity, the emission peaks of TAPA(a-b) became red-shifted and the fluorescence intensity decreased (Φf-DCM=0.001), due to energy gap law. By the time-resolved fluorescence spectra, we have proved that the emitting state of TAPA(a-b) in toluene is ICT state. It has been found out that the introduction of alkyl chain is not only helpful to improve the solubility, but also to strengthen the fluorescence in aggregation form. The two-photon absorption cross sections of TAPA(a-b) in different solvents was determined by the open aperture Z-scan technique and the consistent law was found, which isσdata grew with the increase of solvent polarity. Besides,σdata of TAPA-b is larger than that of TAPA-a because of the introduction of alkyl chain.In Chapter 4, a new starburst triphenylamine-based TPA compounds (BTD-Ⅰ～Ⅲ) with 2,1,3-Benzothiadiazole as the core were synthesized and their photophysical properties are investigated, in which BTD-Ⅰshows aggregation-induced enhanced emission (AIEE) and BTD-Ⅱ～Ⅲshow AIE phenomenon. Their values of TPA cross section (σ) are 182,460 and 652 GM at 800 nm, respectively. All of them emit red or purple light in aggregation due to the strong acceptor 2,1,3-Benzothiadiazole.In Chapter 5, conclusion.