摘要:本”Resolve”計劃結合台、法三個互補團隊將進行可以大面積列印OLED的材料及技術開發研究。台灣團隊由臺大(NTU)化學系汪根欉研究室負責合成關鍵發光材料,以縮二脲(biuret)作為分子終端基團可以經由分子間氫鍵自組裝成發光囊泡(vesicle),NTU團隊將以此為基礎,在分子設計中引入傳統的紅、綠、藍螢光基團、圓偏振螢光(circularly polarized fluorescence)基團或側基、熱激延遲螢光(thermally activated delayed fluorescence,TADF)基團最為核心,透過biuret的自組裝行為開發新的功能性發光囊泡,以提供法國兩個團隊進行螢光及相關特性分析及利用列印方法製作高解析大面積OLED的技術開發。法國團隊將由D. Bassani 教授(Institute of Science Molecular, ISM)負責,Bassani 教授在光物理、自組裝相關研究有卓越成就,現為RSC 期刊Photchem. Photobiol. Sci. 主編,法國另一個團隊由L. Hirsh 教授(ISM)負責進行元件製作技術的研發。此台法合組的研究團隊先前曾發表利用自組裝RGB發光囊泡製作高解析度(~20000 dpi) 的OLED元件(ACS Nano, 2016, 10, 998),在此”Resolve”計劃中Bassani 教授將利用其研究室架設的共聚焦螢光顯微鏡並結合原子力顯微鏡之先進技術分析NTU團隊所建構的新穎自組裝螢光、圓偏振、TADF發光囊泡的相關特性,並利用自組裝發光囊泡自我篩選能力完成RGB色素混合卻各自獨立存在之OLED元件。在電致放光元件中,利用傳統的螢光材料之激子的萃取效率低(~25%)的困境,將透過引入具有TADF特性的核心基團解決,本計劃最後將利用此新穎可自組裝成奈米尺度的發光囊泡溶液透過使用先進in-jet印刷技術開發公司 ElorPrintTec 的設備及無塵室完成高解析度大面積OLED RGB 元件製作技術開發開發可列印的大面積OLED元件技術。
Abstract: The Resolve project brings together three complementary teams from France and Taiwan to tackle the future of large-area printable OLED devices. The project relies on the expertise in OLED materials and organic synthesis of K.T. Wong from (NTU). Thanks to biuret molecular recognition groups that are capable of directing the formation of extended sheets that spontaneously form vesicles when dispersed in solution. NTU team will prepare small molecule electroluminescent materials implemented with classical red, green, and blue (RGB) fluorescent core, circularly polarized fluorescent (CPFL) core, thermally activated delayed fluorescent (TADF) core, designed to self-assemble via hydrogen-bonding interactions. Two teams from France, one specialized in supramolecular photochemistry (Institute of Science Molecular, ISM) and one specialized in the fabrication and characterization of organic electronics devices (IMS). The IMS team is lead by D. Bassani, a recognized expert in the area of photochemistry (currently Editor-in-Chief for the RSC journal Photchem. Photobiol. Sci.), and widely known for his work on supramolecular systems. The second IMS team is lead by L. Hirsh, who launched and directed the French GDR in organic electronics for several years. The three teams have a long history of collaborative work and were able, during the course of a previous international project, to demonstrate the fabrication of the first supramolecular OLED device in which the three RGB colors were co-deposited in very close proximity (< 1 µm2). This allows, in principle, to envision OLED devices whose resolution can reach 20000 dpi. In the Resolve project, we will take this much beyond the current state-of-the-art by developing systems that can spontaneously self-sort from the same solution into separate aggregates of different colors. This will not only allow us to prepare multi-color pixel active layers in one single deposition, but will also allow error correction during the deposition of individual colors, should any one color bleed into the adjacent pixel. Other advanced functionalities will also be implemented using supramolecular building blocks as a means to a functions-based approach to future OLED devices. These will be investigated at the photophysical level using advanced time- and spaced-resolved confocal microscopy. We have modified our instrument to collect electroluminescence mapping images and it is now coupled to a conductive AFM for in-depth measurements. Finally, we will concentrate on the development of solution-based printing techniques that are compatible with current manufacturing protocols. These include state-of-the-art ink-jet printing available at the ElorPrintTec clean room facilities that will allow us to prepare large-area devices and study the effects of ink composition and deposition conditions on the self-assembly processes and device performance.