A Simple and Strong Electron‐Deficient 5,6‐Dicyano[2,1,3]benzothiadiazole‐Cored Donor‐Acceptor‐Donor Compound for Efficient Near Infrared Thermally Activated Delayed Fluorescence
Jakkapan Kumsampao, Chaiyon Chaiwai, Pongsakorn Chasing, Thanyarat Chawanpunyawat, Supawadee Namuangruk, Taweesak Sudyoadsuk, Vinich Promarak
Abstract
Abstract Despite the success of thermally activated delayed fluorescent (TADF) materials in steering the next generation of organic light‐emitting diodes (OLEDs), effective near infrared (NIR) TADF emitters are still very rare. Here, we present a simple and extremely high electron‐deficient compound, 5,6‐dicyano[2,1,3]benzothiadiazole (CNBz), as a strong electron‐accepting unit to develop a sufficiently strong donor‐acceptor (D−A) interaction for NIR emission. End‐capping with the electron‐donating triphenylamine (TPA) unit created an effective D−A−D type system, giving rise to an efficient NIR TADF emissive molecule (λ em =750 nm) with a very small ΔE ST of 0.06 eV. The electroluminescent device using this NIR TADF emitter exhibited an excellent performance with a high maximum radiance of 10020 mW Sr −1 m −2 , a maximum EQE of 6.57% and a peak wavelength of 712 nm.