Efficient Exciplex‐based Green and Near‐Infrared Organic Light‐Emitting Diodes Employing a Novel Donor‐Acceptor Type Donor
Juewen Zhao, Jun Ye, Xiaoyang Du, Caijun Zheng, Zeyu He, Haoyu Yang, Ming Zhang, Hui Lin, Silu Tao
Abstract
Abstract Widely investigated thermally activated delayed fluorescence (TADF) can be achieved by intramolecular and intermolecular charge transfer between an electron donor and electron acceptor which corresponds to a TADF material and exciplex, respectively. However, the development of efficient organic light‐emitting diodes (OLEDs) based on an exciplex lags far behind the development of those based on efficient TADF materials. In this work, a novel D‐A type electron donor TPAFPO was designed and synthesized. TPAFPO:PO‐T2T exhibits a small Δ E ST of 79 meV and significant delayed emission, demonstrating TADF characteristics. OLEDs based on TPAFPO:PO‐T2T exhibit a low turn‐on voltage of 2.4 V and high an EQE value of 17.0%. Besides, NIR OLEDs utilizing TPAFPO:PO‐T2T as host exhibit a turn‐on voltage of 3.0 V and high EQE of 9.2% with a NIR emission peak at 690 nm. Furthermore, solution‐processed exciplex and NIR devices also can maintain high efficiencies of 15.1% and 8.1%, respectively.