Abstract
We study the nature and dynamics of spin-dependent charge-carrier recombination in tris(8-hydroxyquinolinato) aluminum () films in light-emitting diodes at room temperature using continuous-wave and pulsed electrically detected magnetic resonance (EDMR) spectroscopy. We find that the EDMR signal is dominated by an electron-hole recombination process and another weaker EDMR signal, the fundamental nature of which is investigated. From the pulsed EDMR measurements, we obtain a carrier-spin-relaxation time, = 45 ns ± 25 ns, which is much shorter than that of in conjugated polymers, but relatively long for a molecule containing elements with a high atomic number. Using multifrequency continuous-wave EDMR spectroscopy, we obtain the local hyperfine field distributions for electrons and holes, as well as their respective spin-orbit-coupling-induced g-factor and g-strain values.
- Received 2 April 2020
- Revised 25 June 2020
- Accepted 20 July 2020
DOI:https://doi.org/10.1103/PhysRevApplied.14.034012
© 2020 American Physical Society