Effect of bilayer number on the photoluminescent property of TPE-based self-assembled film
Effect of bilayer number on the photoluminescent property of TPE-based self-assembled film
复制标题
双层数对TPE基自组装薄膜光致发光性能的影响
DOI：
10.1007/s11434-013-5943-7
复制
发表时间：
2013-08-01
影响因子：
--
通讯作者：
Dong YuPing
中科院分区：
文献类型：
--
作者：
Chen DiDi;Feng Xiao;Dong YuPing
四苯基乙烯（TPE）衍生物在自由三维空间中聚集时，已被证明是典型的聚集诱导发射（AIE）发光物质。为了揭示尺寸大小对TPEs AIE性能的影响，我们利用四（4-羟基苯基）乙烯（TPE-4OH）和1,4-苯二胺重氮盐（BD）通过逐层自组装技术制备了超薄膜（TPE-4OH/BD LBL SA薄膜）。薄膜中TPE-4OH与BD的相互作用在紫外照射下由静电力和氢键转化为共价键。采用荧光发射光谱、紫外-可见吸收光谱和原子力显微镜对tpe基自组装膜的双分子层数与光致发光的关系进行了评价。实验结果表明，三层双分子层的tpe基薄膜仅表现出AIE特征，而当双分子层数大于3层时，薄膜的荧光发生随机变化。认为具有有限分子长度（z轴）和无限聚集空间（y轴）的TPE-4OH/BD LBL SA薄膜的荧光特性主要受两种竞争效应支配，一种是TPE-4OH/BD交联结构中通过短分子间相互作用部分限制分子内旋转，另一种是通过不受限制的分子内旋转或π-π相互作用使其激发态失活。
Tetraphenylethylene (TPE) derivatives have been proved to be typical aggregation-induced emission (AIE) luminogens when they were aggregated in the free three-dimensional space. In order to reveal the effect of the dimensional degree on AIE property of TPEs, we utilized tetra(4-hydroxyphenyl)ethylene (TPE-4OH) and 1,4-benzenediamine diazonium salt (BD) to fabricate the ultra-thin films (TPE-4OH/BD LBL SA film) through layer-by-layer self-assembled technique. The interaction between TPE-4OH and BD in the films was converted from electrostatic force and hydrogen-bond to covalent bonds through photodecomposition of diazonium groups under UV irradiation. Fluorescence emission spectroscopy, UV-Vis absorption spectroscopy and atomic force microscope were carried out to evaluate the relationship between bilayer number and photoluminescence of the TPE-based self-assembled films. The experimental results showed that the TPE-based film with three bilayers only displayed AIE character, whereas the fluorescence of the film became randomly changed if the bilayer number was above three. It is supposed that the fluorescence property of the TPE-4OH/BD LBL SA film with limited molecular length inz-axis and infinite aggregation space inx- andy-axis is dominated by two competitive effects, one is the partial restriction of intramolecular rotation through short intermolecular interactions in cross-linked structure of TPE-4OH/BD, and the other is deactivation of its excited state through unrestricted intramolecular rotations or π-π interactions.