Ultrahigh‐Efficiency Green PHOLEDs with a Voltage under 3 V and a Power Efficiency of Nearly 110 lm W⁻¹ at Luminance of 10 000 cd m⁻²

Maintaining high power efficiency (PE) under high brightness is still a pressing problem for the practical application of organic light‐emitting diodes (OLEDs). Here, ultrahigh‐efficiency green phosphorescent OLEDs (PHOLEDs) with a record‐low voltage at luminance above 5000 cd m −2 are fabricated, by developing a novel anthracene/pyridine derivative as the electron‐transporting material (ETM) combined with a material displaying thermally activated delayed fluorescence as the host. The pyridine units of the ETM not only facilitate charge injection, but also enhance the electron‐transporting mobility, profiting from the closely packed molecules caused by the intermolecular H‐bonding. The optimized green PHOLEDs show record‐low driving voltages of 2.76 and 2.92 V, with EQEs/PEs of 28.0%/102 lm W −1 and 27.9%/97 lm W −1 at 5000 and 10 000 cd m −2 , respectively. Furthermore, device optimization exhibits an unprecedented high PE of 109 lm W −1 at 10 000 cd m −2 with voltage under 3 V. Those values are the state‐of‐the‐art among all reported green OLEDs so far, paving their way toward practical applications.