摘要
溶液法在有机发光二极管(OLED)的制备工艺中具有成本低和材料利用率高的优势.在溶液加工有机发光二极管(SOLED)的多层架构中,空穴传输层所用材料(HTM)对于级联空穴注入至关重要.然而,常用的商业HTM材料TFB由于能级不匹配和上层溶剂再溶解问题而使器件性能受限,因此需要可交联的HTM(X-HTM)以获得更好的器件性能.在本研究中,我们设计合成了两种新型小分子X-HTMs,FTPA-V和FPCz-V,这两种材料中均引入了热交联的乙烯基团和吸电性三氟甲基基团.所合成的X-HTMs具有优异的膜形貌和溶剂抗性,优化了界面接触.使用X-HTMs显著提高了蓝绿红光SOLEDs的效率和寿命.特别是采用FPCz-V的蓝光SOLED显示出超过150小时的寿命(LT95),是蓝光SOLED寿命的新记录.X-HTMs的电化学稳定性、高键解能和高三线态能级能有效地减少激子湮灭并延长寿命.这些发现体现了交联HTM材料的潜力,推动了稳定的溶液加工发光技术的发展.
Abstract
The solution-processed method for organic light-emitting diodes(OLEDs)offers the benefits of cost-ef-fectiveness and enhanced material utilization.In the multi-layer architecture of solution-processed OLEDs(SOLEDs),the role of hole-transport materials(HTMs)is pivotal for cascade hole injection.However,commercial HTMs such as poly-(9,9-dioctylfluorene-alt-N-(4-sec-butylphenyl)-diphenylamine)(TFB)are hampered by incompatible energy levels and re-dissolution with overlayer solvent,prompting the exploration of cross-linkable HTMs(X-HTMs)for better performance.In this study,we have developed two novel small-molecule X-HTMs,N1,N1'-((perfluoropropane-2,2-diyl)bis(4,1-pheny-lene))bis(N4,N4-diphenyl-N1-(4-vinylphenyl)benzene-1,4-dia-mine)(FTPA-V)and N,N'-((perfluoropropane-2,2-diyl)bis-(4,1-phenylene))bis(9-phenyl-N-(4-vinylphenyl)-9H-carbazol-3-amine)(FPCz-V),which incorporate thermally cross-link-able vinyl groups and electron-rich trifluoromethyl units.The X-HTMs enhance interfacial contact through superior film formation and solvent resistance,along with optimal energy levels.The application of X-HTMs significantly enhances the efficiencies and longevities of blue,green,and red SOLEDs.Specially,blue SOLED incorporating FPCz-V exhibits un-precedented lifetime(LT95)extending to over 150 h,setting a new record for blue SOLEDs.The electrochemistry stability,high bond dissociation energy,and triplet energy levels of X-HTMs can effectively minimize exciton annihilation and prolong the lifetime.These findings underscore the potential of X-HTM optimization to propel the development of stable solution-processed luminescent technologies.
基金项目
National Natural Science Foundation of China(22275003)
Shenzhen Fundamental Research Program(JCYJ20200109140425347)
Development and Reform Commission of Shenzhen Municipality(XMHT20200106002)
Key-Area Research and Development Program of Guangdong Province(2019B010924003)
Guangdong Basic and Applied Basic Research Foundation(2020B1515120030)
Guangdong Key Laboratory of Flexible Optoelectronic Materials and Devices()
Guangdong International Science and Technology Cooperation Base of Optoelectronic Materials and Device Technology()
NETL
NSTL
万方数据