Interfacial dipole dynamics of light-emitting diodes incorporating a poly(amidoamine) dendrimer monolayer

Abstract

We investigate the effects induced by a nonconjugated self-assembled monolayer of poly(amidoamine) (PAMAM) on the work function of thermally evaporated Al-electrodes. We compare results from Kelvin probe measurement of the electrodes work function with electroabsorption characterization of the built-in voltage of polymer light-emitting diodes incorporating them. Interestingly, we find that the PAMAM monolayer decreases the work function by 0.4 eV in a Kelvin probe measurement but that the dipole induced by the PAMAM monolayer is altered by biasing, and that it exhibits a hysteretic behavior in a cyclic voltage scan. © 2010 American Institute of Physics.