摘要
有机电致发光器件(OLEDs)具有低能耗、高效率、高色域等优点,在当前的显示行业中展现出巨大的应用前景。在当前的市场上,主要是通过蒸镀的方式来制造有机发光显示器件。在OLEDs各种制备技术中,喷墨打印相对于目前主流的蒸镀方式,可以有效提高材料利用率,减小资源浪费,然而,在利用喷墨打印制备优质薄膜的实际操作过程中,研究人员发现在薄膜表面经常会出现“咖啡环”效应这种成膜缺陷,这种缺陷的存在不仅影响了膜层质量和器件的性能,同时也在某种程度上制约了喷墨打印技术的进一步发展。通过对喷墨打印技术成膜的一系列相关工作进行整理,总结并分析了喷墨打印成膜缺陷——“咖啡环”的形成原因,并归纳了目前已被证实的可以提高成膜质量的相应策略。针对“咖啡环”现象的主要形成原因,我们主要从抑制液滴内部的毛细流动、增大向内的Marangoni流和控制三相线滑移这三个角度对以往的研究工作进行了分析概括。通过分析总结,发现主要是通过三种途径来达到抑制毛细流动的目的:首先是增加毛细流动阻力,其次还可以调整溶液的蒸发条件,此外依靠粒子间的相互作用也可以达到抑制毛细流动的目的;同时,现在有两种主流的方法来增大向内的Marangoni流,一种是通过改变溶剂组成从而改变液滴表面张力达到优化Marangoni流的目的,另外一种是通过添加表面活性剂来增大Marangoni流;对于控制三相线滑移,通过对以往研究的分析,总结了三种方法,一种是使用电润湿法处理液滴,一种是改变粒子与基板之间的粘滞效应,还有一种是通过对基板进行表面处理来控制三相线滑移。最终,基于以上的一系列优化和改进,在研究人员的不断努力下,目前基本已经可以实现喷墨打印薄膜的均匀调控。
Organic electroluminescent devices(OLEDs)have the advantages of low energy consumption,high efficiency,high color gamut,etc.,and have shown great application prospects in the current display industry.In the current market,organic light-emitting display devices are mainly manufactured by evaporation.In various preparation technologies of OLEDs,inkjet printing can effectively improve material utilization and reduce resource waste compared with current mainstream evaporation methods.However,in the actual operation process of preparing high-quality film by inkjet printing,researchers found that the filming defect of“coffee ring”effect often appears on the surface of the film.The existence of such defects not only affects the quality of the film layer and the performance of the device,but also restricts the further development of inkjet printing technology to some extent.In view of the main causes of the“coffee ring”phenomenon,we mainly analyze and summarize the previous research work from the three aspects of suppressing the capillary flow inside the droplet,increasing the Marangoni flow inward and controlling the three-phase line slip.Through the analysis and summary of these research work,we found that the main purpose is to suppress the capillary flow by three ways:firstly,increase the capillary flow resistance,secondly,adjust the evaporation condition of the solution,and also rely on the interaction between particles can achieve the purpose of inhibiting capillary flow;At the same time,there are two mainstream methods to increase the inward Marangoni flow,one is to optimize the Marangoni flow by changing the solvent composition to change the surface tension of the droplets,and the other is to increase the surfactant Marangoni stream by adding surfactants;For the control of three-phase line slip,we have summarized three methods by analyzing previous studies.One is to use electrowetting to treat droplets,the other is to change the viscous effect between particles and the substrate,and the three-phase line s
作者
曹宝龙
王明昊
李雪
陈淑芬
CAO Bao-long;WANG Ming-hao;LI Xue;CHEN Shu-fen(School of Mechanical Engineering,Nanjing Institute of Technology,Nanjing 211167,China;Institute of Advanced Materials,Nanjing University of Posts and Telecommunications,Nanjing 210023)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2020年第10期3071-3076,共6页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(61274065)
江苏省研究生实践创新项目(SJCX19_0490)
南京工程学院创新基金重大项目(CKJA201602)资助。
关键词
喷墨打印
“咖啡环”效应
液滴沉积
Inkjet printing
“Coffee ring”effect
Droplet deposition
