Air-Stable Ultrabright Inverted Organic Light-Emitting Devices with Metal Ion-Chelated Polymer Injection Layer

• Published in: Nano-micro letters 2022-12, Vol.14 (1), p.14-14, Article 14
• Main Authors: Liu, Shihao, Zang, Chunxiu, Zhang, Jiaming, Tian, Shuang, Wu, Yan, Shen, Dong, Zhang, Letian, Xie, Wenfa, Lee, Chun-Sing
• Format: Article
• Language: English
• Subjects: Air stability; Brightness; Chelation; Devices; Electron injection; Engineering; Inverted organic light-emitting device; Light-emitting devices; Metal ion chelation; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Organic light emitting diodes; Polyethyleneimine; Quantum efficiency; Ultrabright; Zinc
• ISSN: 2311-6706; 2150-5551
• DOI: 10.1007/s40820-021-00745-w

Highlights By using a zinc ion-chelated polyethylenimine as electron injection layer, an inverted organic light-emitting device (OLED) was successfully prepared with an external quantum efficiency over 10% at a brightness of 45,610 cd m −2 . The chelation between zinc ion and amine groups not only passivates polar amine groups, but also fuses separated electronic orbitals. The inverted OLED show an excellent air stability with an operating time of 541 h @ 1,000 cd m −2 without any protection. Here, this work presents an air-stable ultrabright inverted organic light-emitting device (OLED) by using zinc ion-chelated polyethylenimine (PEI) as electron injection layer. The zinc chelation is demonstrated to increase the conductivity of the PEI by three orders of magnitude and passivate the polar amine groups. With these physicochemical properties, the inverted OLED shows a record-high external quantum efficiency of 10.0% at a high brightness of 45,610 cd m −2 and can deliver a maximum brightness of 121,865 cd m −2 . Besides, the inverted OLED is also demonstrated to possess an excellent air stability (humidity, 35%) with a half-brightness operating time of 541 h @ 1000 cd m −2 without any protection nor encapsulation.