Luminescence of tris (8-hydroxyquinoline) aluminium thin films under synchrotron radiation excitation

Abstract

The work is dedicated to the investigation of the luminescent properties of Tris (8-hydroxyquinoline) aluminium (Alq3) thin layers using the conventional spectral methods (cathodoluminescence and photoluminescence), as well as the advanced time-resolved luminescent spectroscopy under excitation by the synchrotron radiation in the fundamental absorption edge of this material. The Alq3 films with a thickness of 100–300 nm were deposited by the PVD (Physical Vapor Deposition) method on silicon substrates. The structural properties of Alq3 layers were studied using scanning electronic microscopy and X ray diffraction. The structure of the luminescence spectra of the Alq3 layer in the green-yellow range at 10 K and 300 K confirms the complex structure of the emission centers of this material, associated with the internal fast radiation transitions in the Al3+ molecule surrounded by three 8-hydroxynoline ligands. It has been determined the energy of creation of excitons associated with Alq3 green emission centers, which has been equal to 6.78 eV and 6.86 eV at 10 K and 300 K, respectively.