Electron-Rich Twistacene-Modified Arylboron Donor-Acceptor Systems: Synthesis, Photophysics, and Electroluminescence with Hot Exciton Response

A series of twistacene-functionalized donor (D)-pi-acceptor (A) derivatives (2-5) have been designed and synthesized, in which twistacene can be regarded as a promising platform for electron-rich systems for fluorescence emitters. The connecting modes and various acceptors are also examined to investigate the effect of structural changes on the photophysical, electrochemical, and thermal properties. The strong electron-withdrawing capability of the arylboron-modified benzonitrile unit can effectively separate the HOMO and LUMO energy levels of 4/5, which is beneficial for the formation of thermally activated delayed fluorescence (TADF) molecules. Cyan and orange organic light-emitting diodes based on 4 and 5 exhibit promising electroluminescence with a maximum brightness of 7643 cd m(-2) for device-4 and 14871 cd m(-2) for device-5.