Substituent Effect on Anthracene-Benzophenone Triad System: Photophysical Properties and Application to OLEDs with “Hot-Exciton” Characteristics

‘‘Hot-exciton’’ materials exhibiting high-lying reverse intersystem crossing (hRISC) are promising candidates for organic light-emitting diode (OLED) materials owing to their improved exciton utilization efficiency and efficiency roll-off. To investigate the excited-state structure–property relationship in anthracene/benzophenone-based materials, we designed and prepared three anthracene-benzophenone derivatives by varying substituents at peripheral benzophenone units, namely, AnBP-F, AnBP-H, and AnBP-OMe. Systematic investigation of the excited-state properties of these compounds and DFT calculations showed that they have hybridized local and charge-transfer (HLCT) characteristics in their emissive transitions. All prepared compounds were adapted in a non-doped OLED device, which exhibited an external quantum efficiency (EQE) of up to 2.88%. To further study the exciton dynamics in the device, magnetoelectroluminescence was measured, which exhibits the combined characteristics of triplet–triplet annihilation (TTA) and HLCT mechanisms.