Stable and Efficient Near-Infrared Organic Light-Emitting Diodes Employing a Platinum(II) Porphyrin Complex

Stable and efficient emitters are highly desired for near-infrared organic light-emitting diodes (NIR OLEDs) due to their extensive applications in biometric authentication, night vision display, and telecommunication. As this technology advances, there is an increasing demand for the development of NIR OLEDs with an emission spectrum beyond 900 nm. This work reports a stable and efficient near-infrared Pt(II) porphyrin complex, i.e., Pt(II) tetra(3,5-difluorophenyl)tetranaphthoporphyrin named PtTPTNP-F₈, of which 84% of the total emitted photons are at wavelengths longer than 900 nm. By introducing fluorine atoms on the meta positions of all four phenyl groups, PtTPTNP-F₈ can successfully overcome the common thermal instability issue emerging from the heavy Pt(II) porphyrin complexes, demonstrating a sublimation yield of above 90%. By carefully choosing the host materials, a NIR OLED device with PtTPTNP-F₈ as an emissive material achieves a high peak device efficiency of 1.9%. Furthermore, devices of PtTPTNP-F₈ fabricated in a stable device structure demonstrate extraordinary operational stability with an LT₉₉ lifetime (time to 99% of the initial photocurrent) of more than 1000 h at a constant driving current density of 20 mA cm^-2.