Enhancing color purity and efficiency of blue TADF OLEDs with MoO₃/Al₂O₃-based distributed Bragg reflector structures

Blue thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) continue to face challenges in color purity and operational stability, despite ongoing advancements in emission mechanisms. In this study, a distributed Bragg reflector (DBR) composed of molybdenum oxide and aluminum oxide was fabricated using thermal evaporation and sputtering and integrated into blue TADF OLEDs. By precisely controlling the number of DBR dyads, the device efficiency was improved by up to 17.8%, while the emission spectrum was narrowed to a full width at half maximum (FWHM) of 54 nm. Additionally, a peak wavelength of 462 nm was achieved, enabling deep-blue emission.