Jump to main content
Jump to site search

Issue 31, 2013
Previous Article Next Article

Eumelanin thin films: solution-processing, growth, and charge transport properties

Author affiliations

Abstract

Eumelanin pigments show hydration-dependent conductivity, broad-band UV-vis absorption, and chelation of metal ions. Solution-processing of synthetic eumelanins opens new possibilities for the characterization of eumelanin in thin film form and its integration into bioelectronic devices. We investigate the effect of different synthesis routes and processing solvents on the growth, the morphology, and the chemical composition of eumelanin thin films using atomic force microscopy and X-ray photoelectron spectroscopy. We further characterize the films by transient electrical current measurements obtained at 50% to 90% relative humidity, relevant for bioelectronic applications. We show that the use of dimethyl sulfoxide is preferable over ammonia solution as processing solvent, yielding homogeneous films with surface roughnesses below 0.5 nm and a chemical composition in agreement with the eumelanin molecular structure. These eumelanin films grow in a quasi layer-by-layer mode, each layer being composed of nanoaggregates, 1–2 nm high, 10–30 nm large. The transient electrical measurements using a planar two-electrode device suggest that there are two contributions to the current, electronic and ionic, the latter being increasingly dominant at higher hydration, and point to the importance of time-dependent electrical characterization of eumelanin films.

Graphical abstract: Eumelanin thin films: solution-processing, growth, and charge transport properties

Back to tab navigation

Supplementary files

Publication details

The article was received on 01 May 2013, accepted on 19 Jun 2013 and first published on 19 Jun 2013


Article type: Paper
DOI: 10.1039/C3TB20630K
Citation: J. Mater. Chem. B, 2013,1, 3836-3842
  •   Request permissions

    Eumelanin thin films: solution-processing, growth, and charge transport properties

    J. Wünsche, F. Cicoira, C. F. O. Graeff and C. Santato, J. Mater. Chem. B, 2013, 1, 3836
    DOI: 10.1039/C3TB20630K

Search articles by author

Spotlight

Advertisements