Thermally activated delayed fluorescence materials based on benzophenone derivative as emitter for efficient solution-processed non-doped green OLED

摘要

A series of thermally activated delayed fluorescence materials based on benzophenone derivatives have been synthesized by Ullmann coupling reaction. The optical, electrochemical and thermal properties of benzophenone derivatives were-systematically characterized. In comparison with the reported thermally activated delayed fluorescence materials based on benzophenone derivatives, bis-{4-[3,6-bis(3,6-di-tert-butyl-carbazol-9-yl)carbazol]-9-yl-phenyl)-methanone exhibited better solubility and smaller energy gap between the singlet and triplet excited states (0.08 eV). The solution-processed non-doped green OLED using this novel material as an emitter exhibited a low turn-on voltage of 4.5 V, a maximum current efficiency of 9.2 cd A(-1), a high external quantum efficiency of 4.3%, and a maximum luminance of 4200 cd m(-2). (C) 2016 Elsevier Ltd. All rights reserved.