Spin Relaxation Mechanisms in the Organic Semiconductor Alq3

Abstract

We have measured the longitudinal (T1) and transverse (T2) spin relaxation times in the organic semiconductor tris(8-hydroxyquinolinolato aluminum)—also known as Alq3—at different temperatures. These measurements shed some light on the spin relaxation mechanisms in the organic. The two most likely mechanisms affecting T1 are hyperfine interactions between carrier and nuclear spins, and the Elliott-Yafet mode. On the other hand, the dominant mechanism affecting T2 of delocalized electrons in Alq3 remains uncertain, but for localized electrons (bound to defect or impurity sites), the dominant mechanism is most likely spin-phonon coupling.