苯并噻唑盐衍生物的超快非线性吸收动力学研究

发布时间：2018-02-20 00:57

  本文关键词： 苯并噻唑盐衍生物 Z扫描 反饱和吸收 泵浦探测技术 瞬态吸收谱　出处：《哈尔滨工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：非线性光学的快速发展离不开非线性光学材料的支持,合理的设计和优化材料成为人们关注的焦点。苯并噻唑盐类表现出强的非线性吸收响应,是很好的非线性光学材料。它有好的荧光特性和强的吸电子能力,在显示、照明以及染料太阳能电池中具有好的应用前景。本论文对三种不同取代基的苯并噻唑盐进行研究,通过量子化学计算中的密度泛函理论方法,计算能级宽度和前线轨道的贡献变化,对比发现取代基为咔唑的苯并噻唑分子电荷转移能力强。利用可调谐的飞秒激光进行不同波长的Z扫描实验来研究三种分子电荷转移对三阶非线性的影响。三种分子溶液在600-800 nm表现出反饱和吸收现象,再用不同能量下的Z扫描实验确定反饱和吸收的机制是双光子诱导激发态吸收,并通过理论分析,数据拟合得到相应的物理参数,数据结果表明,取代基为咔唑的苯并噻唑盐三阶非线性效应最强。三种分子溶液在532 nm Z扫描实验表现出不同的非线性现象,取代基为苯环的苯并噻唑盐表现出饱和向反饱和吸收转换,结合飞秒泵浦探测技术,解释了其转化的原因。最后通过皮秒简并泵浦探测技术和瞬态吸收谱,研究三种不同取代基的苯并噻唑盐激发态吸收特性,确定分子的能级结构以及速率方程,结合皮秒Z扫描实验确定了各能级的物理参数。分析对比三种分子材料的激发态寿命,发现通过合理的改变有机分子的取代基可以调控激发态寿命,这表明苯并噻唑盐衍生物在非线性光学器件应用中具有巨大的潜力。
[Abstract]:The rapid development of nonlinear optics can not be separated from the support of nonlinear optical materials. Reasonable design and optimization of materials have become the focus of attention. Benzothiazole salts exhibit strong nonlinear absorption response. It is a good nonlinear optical material. It has good fluorescence properties and strong electron absorption ability. It has a good application prospect in display, illumination and dye solar cells. In this paper, three kinds of benzothiazole salts with different substituents are studied. The energy level width and the contribution of the frontier orbit are calculated by using the density functional theory method in quantum chemical calculation. The charge transfer ability of benzothiazole with carbazole substituent was found to be strong. The effects of three molecular charge transfer on the third order nonlinearity were studied by using tunable femtosecond laser at different wavelengths. The molecular solution exhibits reverse saturation absorption at 600-800 nm. The mechanism of reverse saturation absorption is found to be two-photon induced excited state absorption by using Z-scan experiments with different energies. The corresponding physical parameters are obtained by theoretical analysis, and the results show that the two photon induced excited state absorption is the main mechanism of anti-saturation absorption, and the corresponding physical parameters are obtained by theoretical analysis. The third order nonlinear effect of benzothiazole salts with carbazole substituents was the strongest. The three kinds of molecular solutions showed different nonlinear phenomena in 532nm Z scanning experiments. The benzothiazolium salts with benzothiazolium substituents as benzene rings showed a saturation to reverse saturation absorption transition. Combined with femtosecond pumping detection technology, the reason of its conversion is explained. Finally, the excited state absorption characteristics of three benzothiazole salts with different substituents are studied by picosecond degenerate pump detection technique and transient absorption spectrum. The energy level structure and rate equation of the molecule are determined. The physical parameters of each energy level are determined by picosecond Z scan experiment. The excited state lifetime of three kinds of molecular materials is analyzed and compared. It is found that the lifetime of excited states can be controlled by changing the substituents of organic molecules reasonably, which indicates that benzothiazolium derivatives have great potential in the application of nonlinear optical devices.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O626.25;O437
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本文编号：1518388