Versatile carbazole and dibenzofuran-based materials for OLEDs: Emitters and exciplex-forming systems

Organic light-emitting diodes (OLEDs) have attracted significant attention in recent decades due to their exceptional advantages. While they are already integrated into numerous commercial products, ongoing challenges related to stability and efficiency have motivated us to develop two new multifunctional compounds, BeCzMFI and BbCzMFI. These compounds are based on a methoxydibenzofuran-carbazole electron-donating core with additional aliphatic chains to enhance film-forming properties. They exhibit excellent thermal and morphological stability, along with favorable photophysical properties, making them promising candidates for OLED applications. These materials can function as both emitters and host materials, either as standalone hosts or as components of exciplex host systems when combined with an acceptor material (CN-T2T). We investigated their performance in blue and red OLEDs, finding that exciplex formation enhances carrier balance and energy transfer efficiency. The blue devices using BeCzMFI and BbCzMFI as emitters exhibited efficient exciton harvesting and carrier balance, leading to high luminance with an external quantum efficiency (EQE) of 10.4 %. Meanwhile, red phosphorescent OLEDs incorporating these materials as exciplex hosts achieved a maximum luminance exceeding 30,000 cd/m² and an EQE of 13.6 %. These results highlight the potential of these multi-function materials in advancing OLED performance by enabling both conventional and exciplex-based emission mechanisms.