Two-Photon Absorption and Optical Power-limiting Properties of Three- and Six-Branched Chromophores Derived from 1,3,5-Triazine and Fluorene Units

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/61404

Title:	Two-Photon Absorption and Optical Power-limiting Properties of Three- and Six-Branched Chromophores Derived from 1,3,5-Triazine and Fluorene Units
Authors:	俞媛;Febriani,Yuyun
Contributors:	化學學系
Keywords:	雙光子吸收;Two-Photon Absorption
Date:	2013-08-08
Issue Date:	2013-10-08 15:07:39 (UTC+8)
Publisher:	國立中央大學
Abstract:	在本論文中系統性地探討含有三?單元結構的數個染料分子之線性光學與非線性光學性質。線性光學性質實驗包含線性吸收光譜、線性螢光光譜、螢光量子產率與生命期。線性螢光光譜實驗結果指出，模型分子1?3會因為分子內電荷轉移（Intramolecular Charge-Transfer）具有較大的Stokes shifts。利用雙光子誘導螢光技術量測得到這些模型分子在690 nm處的雙光子吸收截面值分別為220.46 GM、3134.16 GM以及1873.74 GM。由此結果得知延長外圍分子共軛結構與增加推電子性官能基的數目可有效提升雙光子激發截面。另外，利用奈秒雷射進行光學限幅能力研究的結果指出模型分子1?3皆在690 nm展現良好的光學限制特性。這些初步的結果顯示，多岐化三?類分子具有光限幅之應用潛力。 This research focuses on studying structure-property relationship, exploring two-photon absorption properties and optical power-limiting properties as one of the applications derived from multi-branched triazine. Three new multi-branched triazine compounds : three- and six-branched (compound 1-3) have been designed and synthesized. Their photophysical properties were studied by one-photon fluorescence, fluorescence quantum yield, life-time and two-photon absorption (2PA) cross-section. One-photon fluorescence experimentally was shown that the chromophores (1-3) possess larger Stokes shifts on their ?uorescence emission mainly due to intramolecular charge-transfer (ICT). 2PA cross-section measured by two-photon-excited fluorescence (2PEF) technique were determined to be 220.46, 3134.16, and 1873.74 GM for compound 1,2, and 3, respectively at 690 nm. This result indicates that increasing the branch number incorporated to original D-π-A structure frame work could be an effective approach to get the strong molecular 2PA and shown that using a σ-electron pair as bridge might be an efficient way to transfer charge as well as a π-bridge. At the same time, the power-control properties for these chromophores have been investigated by using a tunable nanosecond laser probed at 690 nm and shown that these chromophores have good optical-limiting behavior. These initial results demonstrated that multi-branched triazine chromophores are a highly suitable class of two-photon absorbing materials and would provide attractive potential application in the optical-limiting ?eld.
Appears in Collections:	[Graduate Institute of Chemistry] Electronic Thesis & Dissertation

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