Aluminium terbium alloys were prepared by simultaneous thermal evaporation resulting in a thin film library covering a 5 to 25 at.% Tb compositional spread. Synchrotron x-ray diffraction (XRD) proves all of the alloys to be amorphous. Scanning electron microscopy (SEM) measurements reveal the structural changes upon increase in Tb content with the formation of small, Tb-rich segregations right before a drastic change in morphology around 25 at.% Tb. Anodic oxides were formed systematically in cyclic voltammograms using scanning droplet cell microscopy. Coulometric analysis revealed a linear thickness over formation potential behaviour with film formation factors ranging from 1.2 nm V−1 (5 at.% Tb) to 1.6 nm V−1 (25 % Tb). Electrochemical impedance spectroscopy was performed for each incremental oxidation step resulting in a linear relation between inverse capacity and formation potential with dielectric constants ranging from 8 (5 at.% Tb) to 16 (25 at.% Tb).

Metal oxide thin films for soft and flexible electronics require low cost, room temperature fabrication, and structuring processes. We here introduce an anodic printing process to realize the essential building blocks of electronic circuitry, including resistors, capacitors, field-effect transistors, diodes, rectifiers, and memristors directly on imperceptible plastic substrates. Largely independent on surface properties, we achieve high-quality, few nanometer thin dielectric and semiconducting films even on rough substrates via localized anodisation of valve metals using a scanning droplet cell microscope. We demonstrate printing-like fabrication of 3D multilayer solid-state capacitors with a record-high areal capacity of 4 µF cm −2 . Applicable to the whole class of valve metals and their alloys, our method provides a versatile fabrication technique for the circuits that empower the flexible and stretchable electronics of tomorrow.

Cobalt-nickel material libraries were electrodeposited in two different types of modified Hull cells. Chloride and sulphate based electrolyte baths, the influence of the overall applied current density, cobalt concentration in the bath and addition of citrate as complexing agent were studied. The experiments suggested a higher cobalt content in the deposits for relatively low overall applied current densities and higher Co 2þ concentrations in the electrolyte bath. For the vast majority of the cobalt-nickel material libraries, a transition from anomalous to normal co-deposition behaviour was found as a result of the current density gradient establishing in the Hull cell during electroplating. Further examination was carried out by scanning electron microscopy (SEM), revealing a changing surface morphology within a material library depending on the cobalt content and the current density. X-ray diffraction (XRD) showed separate and mixed face-centred cubic (fcc) and hexagonal close-packed (hcp) crystallographic structures.Cobalt-nickel composition gradient obtained from two different Hull cell modifications including SEM micrographs of the material library deposited in the lying Hull cell.

A full cobalt-copper material library was successfully prepared from a single experiment by galvanostatic electrodeposition using a modified Hull cell. X-ray fluorescence spectroscopy (XRF) measurements showed, that a composition gradient of 28-96 at.% copper could be achieved. The change of the surface morphology and topography along the material library was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. X-ray diffraction (XRD) revealed a Vegard-like behavior of the face-centered cubic (fcc) cobalt-copper solid solution, as the lattice constant a can be linearly correlated with the atomic copper ratio. The work function, determined from scanning Kelvin probe (SKP) measurements, was expected to decrease gradually with increasing copper content, but was found to be highest (4.86 eV) for a shiny area within the material library (48-62 at.% Cu), indicating higher nobility. This result was confirmed by localized corrosion potential (E corr ) determinations performed by scanning droplet cell microscopy (SDCM). The unexpected high nobility in work function and E corr for this region go hand in hand with a minimum in surface roughness within the material library.

Two types of nonbreakable, flexible microreference electrodes filled with gel-electrolytes were prepared for use in solutions with alkaline and neutral pH. The electrodes are intended for electrochemical measurements, in which chloride-free conditions are important. Due to the flexible, bendable construction of the electrodes, electrochemical experiments at locations difficult to access with common reference electrodes are enabled. Hg|HgO-type electrodes were prepared from amalgamated Au wires, followed by oxidation of the amalgam, which is mounted in a PTFE tube filled with 0.1M NaOH solution immobilized in a PAA-g-PEO gel. The potential of this type of electrode was found to be 0.162 ± 0.002 V (SHE) at room temperature. Cu|CuSO 4 electrodes, consisting of a Cu wire immersed in a saturated CuSO 4 solution jellied with gelatin, showed a stable open-circuit potential of 0.312 ± 0.001 V (SHE). Further characterization of the electrodes was performed in terms of electrochemical impedance spectroscopy and micro-polarization measurements. As an alternative to the flexible electrodes, rigid electrodes in glass enclosure were fabricated in analogy to the flexible-type electrodes.