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Mechanical behavior of fivefold twinned silver nanowires and nanowire films by means of in situ tensile tests in TEM

Wednesday (28.09.2016)
09:15 - 09:30
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Organic (opto)electronics have undergone a rapid development in recent years. Major advantages compared to their inorganic counterparts are that they can be manufactured on flexible substrates. Silver nanowire (Ag NW) films are highly promising as flexible transparent electrodes e.g. for organic solar cells (OCS), as they fulfill the requirement of a low sheet resistance combined with a high transparency. Indium tin oxide (ITO) which is still the most commonly used material behaves brittle under deformation and is relatively expensive. On a macroscopic scale bending tests revealed the excellent performance of Ag NW films, since the increase of electrical resistance is small compared to ITO films. To complement the macroscopic bending tests, understand failure mechanisms on a microscopic scale and prospectively optimize the deformation behavior of AgNW electrodes in situ mechanical testing in the TEM are conducted. The Ag NWs are prepared in a Focused Ion Beam and mechanical testing is performed with the Hysitron PI95 TEM Picoindenter. On a nanometer scale tensile tests of single 5-fold twinned Ag NWs show a ductile behavior and a size effect of the tensile strength. The pristine NWs are almost defect free except for the twin boundaries. In situ testing reveals nucleation and propagation of partial dislocations during straining resulting in stacking faults on inclined glide planes. Current investigations are conducted on further characterization of the nucleated defects. Moreover, in situ tensile tests of AgNW films on the micrometer scale are carried out in order to understand the mechanical failure of NW junctions and their role in the degradation of Ag NW transparent electrodes.

 

Speaker:
Nadine Schrenker
Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Additional Authors:
  • Dr. Mirza Mackovic
    Friedrich-Alexander University Erlangen-Nürnberg
  • Manuela Göbelt
    Max Planck Institute for the Science of Light, Erlangen
  • Prof. Dr. Silke Christiansen
    Max Planck Institute for the Science of Light (Erlangen), Helmholtz Centre Berlin for Materials and Energy
  • Prof. Dr. Erdmann Spiecker
    University of Erlangen-Nuremberg

Dateien

Category Short file description File description File Size
Präsentation TEM images revealing defect structures of Ag NWs. (a) FIB prepared cross-section. The HAADF image reveals the five twins on {111} planes. (b) STEM image of an Ag NW after tensile testing, illustrating a ductile behavior. (c) Post mortem TEM image of the wire shown in (b) revealing nucleated partial dislocations. 135 KB Download