  This work presents conclusive observations about the long lasting topic of
eumelanins' electronic vs. ionic conduction, allowing to access unprecedented
conductivity of this mammal pigment. Key strengths of the study include, the
easy eumelanin thin film fabrication protocol based on solvent free and high
vacuum annealing technology; the first achievement of eumelanin conductivity up
to 10^2 S/cm, an exceptional increase of over nine order of magnitude with
respect to commonly recorded values; decisive demonstration of the electronic
nature of charge transport in eumelanins. Overall these elements provide the
reversal of the long lasting paradigm attributing a key role to water in
eumelanin electrical conductivity, opening - thanks to the conductivity level
achieved - to a completely new perspective for the eumelanin exploitation in
organic electronics and bioelectronics.
