Neutral tris/bis-bidentate Ir(III) and Pt(II) phosphors for efficient near-IR OLEDs

Abstract

Near infrared emitters have recently received immense attention due to their interesting potential applications in the field of night vision display, bio-imaging, medical treatment, 3D depth sensing, and bio-wearable devices etc. The development of NIR emitter is challenging because of their low radiative quantum yield associated with so-called energy gap law or faster non-radiative decay. Therefore, reducing the difference between HOMO and LUMO is the first step and also reducing/avoiding the quenching process (non-radiative transition) is a key to achieve high efficient NIR emitters. We believe that rigid naphthalene benzimidaole (NI-Benz) chromophoric unit can be one of the best chromophores to achieve dark red/near infrared emitters instead of using the traditional phenyl-pyridine moieties. In addition, tuning the color of the final emitter can be achieved by the introduction electron donating/withdrawing units on the NI-Benz framework.