交联型小分子空穴传输材料在溶液工艺制备有机发光二极管中的应用

Application of Solution-Processed Multi-Layer Organic Light-Emitting Diodes Based on Cross-Linkable Small Molecular Hole-Transporting Materials

相比蒸镀工艺,溶液工艺制备有机发光二极管(OLEDs)具有材料利用率高、设备要求简单、成本低、可制作大尺寸面板等优点,受到了广泛关注。小分子空穴传输材料是有机发光二极管重要组成部分,起到传输空穴和阻挡电子的作用,在其结构上添加苯乙烯基、氧杂环丁烷等可交联基团,形成适合溶液工艺制备的可交联小分子空穴传输材料,通过热或光的引发形成网络状结构聚合物,进而应用于多层器件结构中,解决层间混溶问题,从而改善器件的效率和稳定性。本文从溶液工艺对材料的要求出发,首先介绍了旋转涂布及喷墨打印工艺的制备方法,评价了不同操作因素对薄膜质量的影响,之后详细介绍各不同交联基团的空穴传输材料,总结并对比各交联基团的优劣,以及对器件性能的影响。最后,展望了可交联空穴传输材料和溶液制备工艺的发展趋势。

Comparing with vacuum evaporation,fabricating organic light-emitting diodes（ OLEDs） by solutionprocessing methods has plenty of merits,such as high material utilization,simple equipment and feasibility of lowcost large size panels,which has drawn much attention. Small molecule hole-transporting materials（ HTM s）are an important part of OLED devices for hole transporting and electron blocking. Cross-linking groups such as styryl,oxetane, etc. are added to the structure to form cross-linkable small molecular hole transporting materials,which are suitable for solution-processed technology. Initiating with the thermal or the ultra-violet irradiation cross-linking curing reaction,the polymer network structure is formed. As applied in the multilayer OLEDs,the inducing of cross-linkable hole-transporting materials can solve the miscibility problem of the interlayers between the emitting material layer（ EM L） and the hole transporting layer（ HTL）,then improve the efficiency and stability of the device consequently. In this paper,according to the requirements of the solution process for the materials,many techniques about spin-coating and ink-jet printing are presented,such as themethods of fabrication, the quality of films affected by manual factors and the comparison of different manufactory measures. Afterwards,to summarize their performance in devices,various cross-linkable HTM s are listed and investigated,such as trifluoroethylene group,styrene group,oxetane group,siloxane group and unsaturated ester group. Finally,the developing trend of cross-linkable HTM s and solution process is introduced.