Efficient terbium complex based on a novel pyrazolone derivative ligand used in solution-processed OLEDs

Lanthanide organic complexes have high color purity with 100% theoretical internal quantum efficiency, making them good candidates for applications in organic light emitting devices. However, highly efficient and stable solution-processed devices based on terbium complexes have not been reported yet. Here, we present a solution-processed OLED using a novel terbium complex based on pyrazolone derivative ligand with pronounced efficiency. The device with co-host of 70% TcTa and 30% OXD-7 showed low turn-on voltage of 2.30 V, maximum current efficiency of 17.16 cd A⁻¹ and external quantum efficiency of 7.15% at 1000 cd m⁻². In addition, presenting a reduced roll-off efficiency compared to other reported terbium complex devices. This high efficiency for solution-processed Tb-based OLEDs clearly indicates the potential application of this Tb-complex in display applications.