title: Morphology, mechanical stability, and protective properties of ultrathin gallium oxide coatings.
abstract: Ultrathin gallium oxide layers with a thickness of 2.8 ± 0.2 nm were transferred from the surface of liquid gallium onto solid substrates, including conjugated polymer poly(3-hexylthiophene) (P3HT). The gallium oxide exhibits high mechanical stability, withstanding normal pressures of up to 1 GPa in contact mode scanning force microscopy imaging. Moreover, it lowers the rate of photodegradation of P3HT by 4 orders of magnitude, as compared to uncovered P3HT. This allows us to estimate the upper limits for oxygen and water vapor transmission rates of 0.08 cm(3) m(-2) day(-1) and 0.06 mg m(-2) day(-1), respectively. Hence, similar to other highly functional coatings such as graphene, ultrathin gallium oxide layers can be regarded as promising candidates for protective layers in flexible organic (opto-)electronics and photovoltaics because they offer permeation barrier functionalities in conjunction with high optical transparency.
authors.affiliation: †Institut für Physik, Ernst-Moritz-Arndt Universität, Felix-Hausdorff-Str. 6, D-17487 Greifswald, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Lawrenz
authors.forename: Philipp
authors.initials: P
authors.lastname: Lange
authors.forename: Nikolai
authors.initials: N
authors.lastname: Severin
authors.forename: Jürgen P
authors.initials: JP
authors.lastname: Rabe
authors.affiliation: †Institut für Physik, Ernst-Moritz-Arndt Universität, Felix-Hausdorff-Str. 6, D-17487 Greifswald, Germany.
authors.forename: Christiane A
authors.initials: CA
authors.lastname: Helm
authors.affiliation: †Institut für Physik, Ernst-Moritz-Arndt Universität, Felix-Hausdorff-Str. 6, D-17487 Greifswald, Germany.|§Applied Physics, Chalmers University of Technology, Fysikgränd 3, SE-412 96 Gothenburg, Sweden.
authors.forename: Stephan
authors.initials: S
authors.lastname: Block