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

dc.contributorUniversidade Estadual Paulista (UNESP)
dc.creatorWünsche, Julia
dc.creatorCicoira, Fabio
dc.creatorGraeff, Carlos Frederico de Oliveira
dc.creatorSantato, Clara
dc.date2014-05-27T11:30:11Z
dc.date2016-10-25T18:52:45Z
dc.date2014-05-27T11:30:11Z
dc.date2016-10-25T18:52:45Z
dc.date2013-08-21
dc.date.accessioned2017-04-06T02:35:08Z
dc.date.available2017-04-06T02:35:08Z
dc.identifierJournal of Materials Chemistry B, v. 1, n. 31, p. 3836-3842, 2013.
dc.identifier2050-7518
dc.identifier2050-750X
dc.identifierhttp://hdl.handle.net/11449/76306
dc.identifierhttp://acervodigital.unesp.br/handle/11449/76306
dc.identifier10.1039/c3tb20630k
dc.identifierWOS:000321905900013
dc.identifier2-s2.0-84880578281.pdf
dc.identifier2-s2.0-84880578281
dc.identifier0000-0003-0162-8273
dc.identifierhttp://dx.doi.org/10.1039/c3tb20630k
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/897007
dc.descriptionEumelanin 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. This journal is © 2013 The Royal Society of Chemistry.
dc.languageeng
dc.relationJournal of Materials Chemistry B
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.subjectBioelectronic applications
dc.subjectBioelectronic device
dc.subjectChemical compositions
dc.subjectElectrical characterization
dc.subjectElectrical measurement
dc.subjectLayer-by layer mode
dc.subjectSolution-processing
dc.subjectUV-vis absorptions
dc.subjectAtomic force microscopy
dc.subjectDimethyl sulfoxide
dc.subjectHydration
dc.subjectMetal ions
dc.subjectPhotoelectrons
dc.subjectPower quality
dc.subjectSurface roughness
dc.subjectThin films
dc.subjectTransport properties
dc.subjectX ray photoelectron spectroscopy
dc.subjectMelanin
dc.titleEumelanin thin films: Solution-processing, growth, and charge transport properties
dc.typeOtro


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