Enhancing blue TADF narrow-band emission via tandem OLEDs with optical modeling simulation

Multi-resonance thermally activated delayed fluorescence (MR-TADF) materials, based on polycyclic aromatic frameworks, have shown promise in achieving narrow-band emission and high luminous efficiency. In this study, we investigate the performance of a blue MR-TADF material, 2 ' 2'2"-(1,3,5-triazine-2,4,6-triyl) tris(9-(2-(naphthalen-2-yl)phenyl)-9H-carbazole) (TBN-TPA), in tandem OLED devices. Single emitter unit and two emitter unit tandem OLED devices with blue MR-TADF material were explored with optical modeling simulation. More importantly, the tandem architecture assists in realizing narrow-band emission and high color purity via optical interference and microcavity effects, which are essential for meeting BT 2020 standards. TBN-TPA achieves narrow full width at half maximum down to 24 nm and CIE coordinates approaching the blue region in tandem devices. Our work highlights the significant advantages of combining tandem architectures and emerging MRTADF emitters for developing high -performance OLEDs with both high efficiency and wide color gamut. This is the first demonstration of using tandem OLED architecture to improve both efficiency and color purity of a blue multi-resonance TADF emitter. Further research on optimizing tandem structures and designing advanced MR-TADF materials will promote the applications of OLED displays.