A Study Concerning the Electronic Conductivity in Eumelanin Thin Films

TL;DR

This study demonstrates a novel, solvent-free fabrication method for eumelanin thin films achieving unprecedented electronic conductivity up to 10^2 S/cm, confirming electronic charge transport and challenging previous water-dependent conductivity models.

Contribution

Introduces a new fabrication protocol for eumelanin films and reports the first record of conductivity reaching 10^2 S/cm, significantly advancing understanding of eumelanin's electronic properties.

Findings

Eumelanin conductivity up to 10^2 S/cm achieved

Electronic charge transport confirmed in eumelanin

Water's role in conductivity paradigm reversed

Abstract

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.