Charge-injection barriers at realistic metal/organic interfaces: Metals become faceless

Interfaces between the organic semiconductor a-sexithiophene and sputter-cleaned (ideal) metals or contaminated (realistic) metals are investigated by a combined X-ray and UV photoemission spectroscopic study. The experimental results indicate a substantial impact of metal-surface contamination on the electronic properties of the interface. In particular, the hole-injection barrier is almost independent of the type of the underlying metal (see figure).