Enhancing the efficiency and stability of blue thermally activated delayed fluorescence emitters by perdeuteration

Highly efficient and stable blue organic light-emitting diodes (OLEDs), although required for display and lighting applications, remain rare. Here we report a molecular perdeuteration strategy to stabilize blue thermally activated delayed fluorescence (TADF) emitters. Perdeuterated sky-blue TADF emitters exhibit higher efficiencies and doubled device lifetime in OLEDs compared with protonated emitters, owing to suppressed high-energy vibrations. Perdeuteration also leads to blue-shifted and narrowed spectra in the solid state, which in turn improves the Förster energy transfer to the deep-blue final emitter in TADF-sensitized fluorescent OLEDs. These devices exhibit a maximum external quantum efficiency of 33.1% and a lifetime to reach 80% of the initial luminance of 1,365 h with a Commission Internationale de l'Eclairage y coordinate of 0.20 at a luminance of 1,000 cd m−2, even outperforming blue phosphorescent OLEDs. Our perdeuteration strategy improves the device performance of blue OLEDs, paving the way for their broader applications in displays and lightings. Molecular perdeuteration of thermally activated delayed fluorescence emitters improves the performance of blue organic light-emitting diodes, enabling a peak external quantum efficiency of 33.1% and a device lifetime to reach 80% of initial luminance of over 1,300 h.