基于四苯乙烯的液晶发光材料的设计合成及其性能研究

发布时间：2018-06-03 13:03

本文选题：聚集诱导发光 + 液晶发光材料　；参考：《湘潭大学》2017年硕士论文

【摘要】：近年来液晶发光材料因兼具液晶的有序性、流动性,以及发光材料优良的光物理性能,引起了科研工作者的关注,并发展为有机电致发光二极管(OLEDs)领域新的研究热点。针对目前液晶发光材料种类少、在固体中易发光淬灭、发光效率不高等科学问题,本论文拟在液晶分子中引入聚集诱导发光概念,减少材料的浓度淬灭,提高液晶材料在固体薄膜中的发光效率。基于这个研究思想,本论文研究工作聚焦于聚集诱导液晶发光材料(AIE-LCs),设计合成了系列基于四苯基乙烯单元的液晶发光材料;利用核磁共振氢谱、碳谱和时间飞行质谱对其结构进行了表征;通过紫外-可见分光光度计、稳态瞬态荧光光谱、循环伏安法、热力学分析和小角X射线衍射研究了这类液晶发光材料的光物理性能、液晶性能和电化学性能;以其中的两个AIE-LCs蓝光材料(TPE-PBN和TPE-2PBN)为发光层掺杂剂,以1,3-二咔唑-9-基苯(mCP)为主体材料,制备了OLEDs器件,研究了分子结构与电致发光性能的关系。本论文主要的研究内容如下:1、设计合成了3种以四苯乙烯-苯基吡啶刚性结构为发光内核,以4-氰基联苯为液晶单元的AIE液晶分子TPE-PBN、TPE-2PBN和TPE-4PBN。利用热力学分析、偏光显微镜和小角X射线衍射研究了分子的液晶性能。通过紫外光谱和荧光光谱分别测试了它们在THF/H2O混合溶液中的光物理性能。研究结果表明:TPE-PBN、TPE-2PBN和TPE-4PBN在THF/H2O混合溶液和固体薄膜中都呈现强烈的聚集诱导发光现象,其中TPE-PBN和TPE-2PBN在固体薄膜中的发光效率高达71%和81%;它们都具有液晶性能,并且随着液晶基元数目的增加,其液晶性能发生变化。以TPE-PBN和TPE-2PBN为发光层掺杂剂,制备了有机电致发光器件,获得了最大亮度为1612 cd/m2,最大发光效率为6.2 cd/A和最大外量子效率(EQE)为4.1%的蓝绿光器件。2、在环金属铂配合物液晶发光材料中引入AIE发光基团四苯基乙烯,合成了2类6种以四苯乙烯和苯基吡啶衍生物作为主配体,以乙酰丙酮以及乙酰丙酮衍生物作为辅助配体的环金属铂配合物液晶发光材料Pt1~Pt6。详细的探讨了这些环金属铂配合物的液晶性能和光物理性能。研究表明:Pt1~Pt6在溶液和固体薄膜中都呈现出强烈的发光,并且环金属配体中的烷基链长度对配合物的紫外和发光性能影响较小;Pt1~Pt6都具有热致型液晶性能,分子的结构变化(主配体中烷基链的长度和辅助配体的结构)对配合物的热力学性能影响较大。其中,只有配合物Pt1具有聚集诱导发光增强效应。本论文构筑了系列基于四苯乙烯-苯基吡啶衍生物的液晶发光材料,详细研究了它们的分子结构-性能关系,初步揭示了聚集诱导液晶发光材料的分子构筑规律,为构筑高效发光的液晶材料提供了新的设计思路。
[Abstract]:In recent years, liquid crystal luminescent materials have attracted the attention of researchers because of their order, fluidity and excellent photophysical properties, and have become a new research hotspot in the field of organic electroluminescent diodes (OLEDs). Aiming at the scientific problems such as few kinds of liquid crystal luminescent materials, easy quenching of luminescence in solids and low luminescence efficiency, this paper intends to introduce the concept of agglomeration induced luminescence into liquid crystal molecules to reduce the concentration quenching of the materials. The luminescence efficiency of liquid crystal material in solid film was improved. Based on this idea, a series of liquid crystal luminescent materials based on tetraphenylethylene unit have been designed and synthesized by focusing on the agglomeration induced liquid crystal luminescence material (AIE-LCsN). The structure was characterized by carbon spectrum and time-of-flight mass spectrometry, and was characterized by UV-Vis spectrophotometer, steady-state transient fluorescence spectroscopy, cyclic voltammetry, The photophysical properties, liquid crystal properties and electrochemical properties of liquid crystal luminescent materials were studied by thermodynamics analysis and small angle X-ray diffraction. Two AIE-LCs blue light materials, TPE-PBN and TPE-2PBN, were used as luminescent layer dopants. The OLEDs devices were prepared by using 1 / 3- dicarbazole-9- (benzyl) mCPs as main materials. The relationship between molecular structure and electroluminescent properties was studied. The main contents of this thesis are as follows: 1. Three AIE liquid crystal molecules TPE-PBN TPE-2PBN and TPE-4PBN were designed and synthesized with tetrastyrene-phenylpyridine rigid structure as the luminescent core and 4-cyano-biphenyl as the liquid crystal unit. The liquid crystal properties of the molecules were studied by thermodynamics analysis, polarizing microscope and small angle X-ray diffraction. Their photophysical properties in THF/H2O mixed solution were measured by UV and fluorescence spectra respectively. The results show that both THF/H2O and TPE-2PBN and TPE-4PBN exhibit strong aggregation induced luminescence in THF/H2O mixed solution and solid film. The luminescence efficiency of TPE-PBN and TPE-2PBN in solid film is as high as 71% and 81% respectively. And with the increase of the number of liquid crystal units, the liquid crystal properties change. Organic electroluminescent devices (OLEDs) were prepared by using TPE-PBN and TPE-2PBN as dopants. A blue-green device with a maximum luminance of 1612 CD / m ~ (2), a maximum luminescence efficiency of 6.2 cd/A and a maximum external quantum efficiency of 4.1% was obtained. The AIE luminescent group tetraphenyl ethylene was introduced into the liquid crystal luminescent material of the cyclometallic platinum complex. Two kinds of six kinds of liquid crystal luminescent materials of platinum complexes with tetrastyrene and phenyl pyridine as main ligands and acetylacetone derivatives as auxiliary ligands were synthesized. The liquid crystal and photophysical properties of these cyclic platinum complexes are discussed in detail. The results show that the ratio Pt1 / Pt6 exhibits strong luminescence in both solution and solid films, and the alkyl chain length in the cyclic metal ligands has little effect on the UV and luminescence properties of the complexes. The changes of molecular structure (the length of alkyl chain in the main ligand and the structure of auxiliary ligand) have great influence on the thermodynamic properties of the complexes. Among them, only the complex Pt1 has agglomeration induced luminescence enhancement effect. In this paper, a series of liquid crystal luminescent materials based on tetrastyrene-phenylpyridine derivatives have been constructed, their molecular structure-performance relationship has been studied in detail, and the molecular architecture of agglomeration induced liquid crystal luminescent materials has been preliminarily revealed. It provides a new design idea for the construction of high efficiency luminescent liquid crystal materials.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O753.2;O644.1

【参考文献】