ABSTRACT
This chapter deals with lanthanide-based molecular complexes that gained interest due to their emerging technological applications. Among all, trivalent europium complexes exhibit efficient red emission in the region around 614 nm due to electric dipole (ED) transition (5D0_7F2). For obtaining efficient red emission from a molecular Eu complex, one needs to choose suitable a multidentate ligand, which is capable of harvesting the photons to the Eu excited levels (5D0). For practical applications (such as OLEDs), the designed molecules need to be doped in the desired host materials (to match the energy levels) and with a suitable device structure. The internal quantum efficiency (IQE) has the probability to reach 100% (100% IQE complexes are rare), but in the case of external quantum efficiency (EQE) 326it is not that much satisfactory. To improve the same, a lot of research effort was directed for the past two decades in designing new functional molecular complexes to use in OELDs. This chapter intends to discuss the recent developments in designing new functional Eu molecular complexes and their use in OLEDs. The energy-efficient lighting and display devices will certainly upgrade human living as well as be ecofriendly.
