High-performance deep-blue phosphorescent organic light-emitting diodes enabled by a platinum(II) emitter

Organic light-emitting diodes (OLEDs) represent a revolutionary technology, that has been successfully commercialized in full-color displays. However, this technology is still severely limited by the low efficiency of blue OLEDs. Developing high-performance blue OLEDs is a major challenge, and emitters are critical for overcoming this issue. Herein, we developed a strategy to design phosphorescent Pt(II) complexes with a locally excited-dominated character and a rigid 3D geometry to suppress intermolecular interactions, enabling robust deep-blue emitters. A bottom-emitting OLED realized a high color purity with a full-width at half-maximum (FWHM) of 17.1 nm, a high maximum brightness of 48968 cd/m2, and high external quantum efficiencies (EQEs) of 31.3%, 27.0%, and 23.6% at 1000, 5000, and 10000 cd/m2, respectively. A top-emitting OLED achieved an enhanced color purity (FWHM = 13.1 nm, CIEy = 0.06), a low running voltage (3.9 V at 1000 cd/m2), and a maximum EQE of 49.5%, and maintained EQEs of 46.4%, 39.5%, and 34.3% at 1000, 5000, and 10000 cd/m2, respectively. The OLED also exhibited a maximum blue index (BI) of 468 cd A-1CIEy-1 and a long half-lifetime of 670 h at an initial luminance of 1000 cd/m2. This study provides a important strategy to develop high-performance deep-blue phosphorescent OLEDs.