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. Issue 19 (28th August 2020) - Kumsampao, Jakkapan
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 (λem =750 nm) with a very small ΔEST 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. Abstract : A simple and extremely strong electron‐accepting 5, 6‐dicyano[2, 1, 3]benzo thiadiazole offered near infrared (NIR) thermally activated delayed fluorescence chromophore with a small single‐triplet splitting (ΔEST ) of 0.06 eV. Its NIR electroluminescent device exhibited an excellent performance with a high maximum radiance of 10020 mW Sr −1 m −2, maximum EQE of 6.57% and peak wavelength of 712 nm.