Study of oxygenation and hydrogenation of tris(8-hydroxyquinoline) aluminum generated by electrode deposition using liquid extraction surface analysis nanoelectrospray ionization mass spectrometry

Abstract

N-oxygenated and N-hydrogenated molecules of 8-hydroxyquinoline with a wide range of N values, generated by the deposition of Al, ITO, and MgAg electrodes on 10 nm thick tris(8-hydroxyquinoline) aluminum (Alq3) molecular films are analyzed by liquid extraction surface analysis combined with nanoelectrospray ionization mass spectrometry (LESA nano-ESI-MS) for the first time. Based on the relative ion intensities of oxygenated and hydrogenated molecules, Al deposition causes greater chemical reduction of Alq3 than ITO and MgAg deposition. Additionally, the relative ion intensities of 1-, 2-, and 3-oxygenated molecules decrease stepwise, so that oxidation of the 8-hydroxyquinoline molecules is thought to proceed stochastically.