Substituent effect on anthracene-benzophenone triad system: Photophysical properties and application to OLEDs with “hot-exciton” characteristics

• Published in: Dyes and pigments 2023-05, Vol.213, p.111171, Article 111171
• Main Authors: Lee, Yeeun, Hwang, Kyo Min, Lee, Sunhee, Park, Bu Bae, Kim, Taekyung, Han, Won-Sik
• Format: Article
• Language: English
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2023.111171

‘‘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. [Display omitted] •Anthracene/benzophenone-based HLCT emitters were prepared by varying substituents at peripheral benzophenone units.•Substituents help to tune the nature of the excited state.•Non-doped OLEDs achieved EQEmax of 2.88%.•Studies on the exciton dynamics of the device indicate that the TTA and HLCT mechanisms concurrently exist.