Enhancing efficiency and brightness of deep-blue phosphorescent OLED enabled by a narrowband Pt(II) emitter

Organic light-emitting diodes (OLEDs) are an advanced technology used in full-color displays. These systems suffer from a main limitation, i.e., the low efficiency of blue OLEDs, and emitters are critical to solve this issue. Here, we developed a new strategy to design robust Pt(II) emitters with enhanced molecular rigidity and increased locally excited character. An obtained Pt(II) emitter exhibited an extremely narrow emission spectrum peaking at 458.6 nm, with a full-width at half-maximum (FWHM) of 16.0 nm and a small Huang-Rhys factor of 0.278, together with a high quantum efficiency of 95%. The emitter-doped OLED peaked at 464 nm with a high color purity (FWHM = 19 nm), and high external quantum efficiencies (EQEs) of 32.6%, 29.4%, and 26.9% at 123, 1000, and 5000 cd/m2, respectively. The device also achieved a record-high maximum brightness of up to 84895 cd/m2 among reported deep-blue OLEDs with Commission Internationale de l’Éclairage y-coordinate