Manfredi Riccardo, Prontera Carmela Tania, Mariano Fabrizio, Pugliese Marco, Maggiore Antonio, Zizzari Alessandra, Cinquino Marco, Tarantini Iolena, Gigli Giuseppe, Maiorano Vincenzo
CNR-NANOTEC-Institute of Nanotechnology, c/o Campus Ecotekne, Via Monteroni, 73100 Lecce, Italy.
Laboratory of Hydrogen and New Energy Vectors (TERIN-DEC-H2V) ENEA-C.R Brindisi, S.S.7 Appia, km 713,700, 72100 Brindisi, Italy.
Materials (Basel). 2025 Jul 9;18(14):3231. doi: 10.3390/ma18143231.
The fabrication of high-performance organic optoelectronic devices using solution-based techniques, in particular inkjet printing, is both a desirable and challenging goal. Organic light-emitting diodes (OLEDs) are multilayer devices that have demonstrated great potential in display applications, with ongoing efforts aimed at extending their use to the lighting sector. A key objective in this context is the reduction in production costs, for which printing techniques offer a promising pathway. The main obstacle to fully printed OLEDs lies in the difficulty of depositing new layers onto pre-existing ones while maintaining high film quality and avoiding damage to the underlying layers. In a bottom-emitting OLED, the electron transport layer (ETL) is the final organic layer to be deposited, making its printing particularly challenging, a process for which only a few successful examples have been reported. In this work, we report on the optimization of a 2,2',2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi)-based ink formulation for ETL printing on an emitting layer composed of 5,10-Bis(4-(3,6-di-tert-butyl-9H-carbazol-9-yl)-2,6-dimethylphenyl)-5,10-dihydroboranthrene (tBuCzDBA). A specific ratio of methanol to diethyl ether was identified as the most suitable for printing the ETL without compromising the integrity of the underlying layer. The printed ETL was successfully integrated into an OLED device, which exhibited a maximum current efficiency of 6.8 cd/A and a peak luminance of about 8700 cd/m. These results represent a significant step toward the development of a fully printed OLED architecture.
使用基于溶液的技术，特别是喷墨印刷来制造高性能有机光电器件，是一个既理想又具有挑战性的目标。有机发光二极管（OLED）是多层器件，已在显示应用中展现出巨大潜力，目前正在努力将其应用扩展到照明领域。在此背景下的一个关键目标是降低生产成本，而印刷技术为此提供了一条有前景的途径。全印刷OLED的主要障碍在于难以在已有的层上沉积新层，同时还要保持高薄膜质量并避免损坏下层。在底部发射OLED中，电子传输层（ETL）是最后沉积的有机层，这使得其印刷极具挑战性，仅有少数成功的报道案例。在这项工作中，我们报告了一种基于2,2',2″-(1,3,5-苯三嗪基)-三(1-苯基-1-H-苯并咪唑)（TPBi）的油墨配方的优化，用于在由5,10-双(4-(3,6-二叔丁基-9H-咔唑-9-基)-2,6-二甲基苯基)-5,10-二氢硼蒽（tBuCzDBA）组成的发光层上印刷ETL。确定了甲醇与乙醚的特定比例最适合印刷ETL，同时又不损害下层的完整性。印刷的ETL成功集成到OLED器件中，该器件表现出最大电流效率为6.8 cd/A，峰值亮度约为8700 cd/m²。这些结果代表了朝着全印刷OLED架构发展迈出了重要一步。
