Tuning energy levels in magnesium modified Alq3

The low molecular weight tris-(8-hydroxyquinoline) aluminum (Alq3) has been modified with magnesium (Mg) incorporation that altered the nature of its opto-electronic characteristics. Ultraviolet photoelectron spectroscopy and optical absorption measurements yielded quantitative energy positions of the electronic states of the Mg:Alq3, its highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO), and resultant shifts thereof due to the Mg incorporation. Consistent lowering of the HOMO and LUMO with Mg incorporation and a new distribution of the HOMO–LUMO separation are observed.