New Alq3 derivatives with efficient photoluminescence and electroluminescence properties for organic light-emitting diodes

Two new ligands prepared under solvent free conditions and five aluminum complexes derived from 8-hydroxyquinoline have been synthesized and characterized. The majority of the new aluminum tris(8-hydroxyquinoline) derivatives have nitrogen functionalities at position-4 of the quinolate ligand. The photoluminescence emission wavelengths of the new Alq3 derivatives are shifted according to the electronic properties of the substituents at position-4. Results from differential scanning calorimetry (DSC) investigations of the new Alq3 derivatives indicate that the complexes 9 and 10 are non crystalline and have higher transition glass temperatures than the parent Alq3. The EL measurements of OLED devices with complexes 7, 9, and 10 as emitters revealed that complexes 7, 9, and 10 are efficient emitters in organic light emitting diodes.