【作者】 李茂；

【导师】 马於光；

【作者基本信息】 吉林大学 ， 有机化学， 2007， 博士

【摘要】 电化学聚合制备聚合物薄膜是一种简单且实用的技术。通常电化学制备的薄膜具有良好的电荷传输性能,但发光性能很差。目前在有机电致发光领域,电化学制备的聚咔唑薄膜主要用来作为多层器件的空穴注入层来改善器件的性能,很少有研究者用电化学聚合材料作为发光层来研究。有机电致发光发展到今天,较高的制备成本仍然是限制这种技术发展的主要原因。电化学聚合制备图案化的薄膜是一种低成本的薄膜制备技术,所以能利用电化学技术制备高效率的有机发光薄膜是十分有意义的。利用循环伏安技术,本论文的工作主要包括四个方面:第一,研究了制备电化学聚合薄膜低效率的原因,设计了新型的高效率的电活性聚合前体,提出了制备高效率发光薄膜的分子设计方法;通过系统地优化电化学聚合条件制备了高效率的类似旋涂的高平整度的发光薄膜,证实了电化学聚合薄膜也可以得到高效率的发光;第二,比较研究了不同支持电解质制备的有机发光薄膜,证明了支持电解质的类型对发光薄膜的物理化学性质,特别是发光效率有很大影响;第三,采用优化的电化学聚合条件,成功地在微米尺度上电化学聚合沉积了高效率的图案化发光薄膜;由于电化学制备图案化发光薄膜在成本上的优势,它可能是更有竞争力的潜在的制备全色显示图案化有机电致发光器件新技术。第四,采用循环伏安技术研究了系列发光配合物电子结构,得出了不同配体改变对配合物分子能级调节的规律,为这类配合物的分子设计和器件制备提供了实验依据。更多还原

【Abstract】 Generally electrosynthesized polymers exhibit electrical conductivity and charge transport, while there is very little attention to optimize the optical proper-ties of emitting layer for organic light-emitting diodes (OLEDs). This is due to a variety of factors, including structural defects and doped counterions presenting in the electropolymerization film, which strongly quench the fluorescence. Up to now, the polycarbazoles prepared by electrosynthesis are mainly applied in OLEDs as the layers for hole injection and/or transport, but have not been applied in OLEDs as the light emitting layer. The electropolymerization film is a low-cost technique for patterned LED, so it’s very significant if the electropolymerization film can be used as new technique of preparing patterned light emitting layer.In the Chapter 2, the electropolymerization behaviors of an electroactive and luminescent compound TCPC as precursor are studied. The large difference in oxidation potential between polyfluorene and the carbazole units ensures the elec-tropolymerization of the pendant carbazole groups without affecting the polymer backbone. The resultant electrochemical deposition (ED) films are characterized by cyclic voltammetry (CV), UV-vis, fluorescence spectra, scanning electron mic-troscopy (SEM) and atomic force microscopy (AFM). Under the CV mode with potential range of–0.5 V~ 0.85 V vs. Ag/Ag+, the coupling reactions between the carbazole units of TCPC are very efficient while the fluorescent trifluorene seg-ment in TCPC is chemically inert in this potential range, which results in a highly fluorescent film formation on indium tin oxide (ITO) electrode. The deposition parameters for preparing the TCPC-based ED films are optimized, and the best ED film gives the fluorescence efficiency of 45.5% with surface roughness of 2.8 nm and morphologic stability as heating up to 180oC. The light-emitting devices (LEDs) using this ED film as light emitting layer with structure ITO/ ED film (~100 nm)/Ba/Al achieve maximum luminescence and external quantum effi-ciency of 4224 cd/m2 @17 V and 0.72% @11.5 V respectively, which are better than the device using TCPC spin-coating films as emitting layer.In the Chapter 3, we studied the effect of supporting electrolytes (TBABF4, TBAPF6 and TBAAsF6) on electrosynthesized luminescent films. The results showed that the electropolymerization rate is the highest when TBAAsF6 was used as supporting electrolyte. The maximum fluorenscence quantum efficiency of these films is up to 65%. The AFM images show the electrosynthesized polym-erization film prepared by TBAAsF6 as supporting electrolyte had more iform morphology in the same electropolymerization conditions. In the meanwhile, this film showed the best performance for OLEDs than the other two supporting elec-trolytes.In the Chapter 4, we studied a simple electropolymerization deposition tech-nique to prepare luminescent and patterned films for LEDs. The luminescent films are deposited directly on the patterned ITO (Indium Tin Oxide) electrodes through an oxidation coupling reaction of an electroactive and luminescent precursor. The films deposited on the ITO strips (width of 200μm) exhibit smooth surface mor-phology (roughness of morphology surface is about 3.1 nm), well roughness in electrode edge of 1~2μm, and high fluorescence quantum efficiency (>60%). The technique provides a facile route towards a patternable luminescent film and de-vice, because such luminescent ED films can be manipulatively deposited on the electrified electrode.In the Chapter 5, to study the electrochemical properties, the energy level and the band gap of a series of phosphorescent Re (I) complexes, (L)Re(CO)3Cl (L=α,α-diamine), the Cyclic Voltammetry (CV) are applied together with the UV-Vis absorption spectra, photoluminescence spectra and the Self-Consistent B3LYP quanta chemical calculation method. Based on the results, the energy level of (L)Re(CO)3Cl are gotten and the influencing rule of ligands are also draw. (L)Re(CO)3Cl complexes have a single oxidation peak and many reduction peaks. These peaks reflect the HOMO and LUMO energy level of (L)Re(CO)3Cl com-plexes, which were made up of Re-Cl hybrid orbital andπ* orbital of diamine ligands, respectively. Compared with the results from spectra, the band gap results of (L)Re(CO)3Cl complexes calculated from CV is mainly corresponding to the triplet energy level.更多还原