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- Friedlein, R, et al.
(författare)
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Ultra-fast charge transfer in organic electronic materials and at hybrid interfaces studied using the core-hole clock technique
- 2011
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Ingår i: JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. - : Elsevier Science B.V., Amsterdam.. - 0368-2048. ; 183:1-3, s. 101-106
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Tidskriftsartikel (refereegranskat)abstract
- The focus of this brief review is the use of resonant photoemission in its "core-hole clock" expression for the study of two important problems relevant for the field of organic electronics: the dynamical charge transfer across hybrid organic-inorganic interfaces, and the intermolecular charge transfer in the bulk of organic thin films. Following an outline of the technique, a discussion of its applicability and a short overview of experimental results obtained thus far, two examples are used to illustrate particular results relevant for the understanding of the charge transport in organic electronic devices. First, for Fe(II)-tetraphenylporphyrin molecules on semi-metallic molybdenum disulfide substrates, the electronic coupling to the substrate and the efficiency of charge transport across the interface different for the individual molecular electronic subsystems is discussed. And second, a discotic liquid crystalline material forming columnar assemblies is used to illustrate ultra-fast intermolecular charge transfer on the order of a few femtoseconds indicating an electronic coupling between the phthalocyanine units stronger than expected from the macroscopic charge transport characteristics of the material. (C) 2011 Published by Elsevier B.V.
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| 2. |
- Kahl, S., et al.
(författare)
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Composite Aluminum-Copper Sheet Material by Friction Stir Welding and Cold Rolling
- 2013
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Ingår i: Journal of materials engineering and performance (Print). - : ASM International. - 1059-9495 .- 1544-1024. ; 22:8, s. 2176-2184
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Tidskriftsartikel (refereegranskat)abstract
- An aluminum alloy and a pure copper material were butt-joined by friction stir welding and subsequently cold rolled. The cold-rolling operation proved to be very advantageous because small voids present after friction stir welding were closed, the interface area per material thickness was enlarged, a thin intermetallic layer was partitioned, and the joint was strengthened by strain hardening. Tensile test specimens fractured in the heat-affected zone in the aluminum material; tensile strengths of the joints exceeded the tensile strengths of the base materials and were as high as 335 MPa. During soft annealing of the composite material, a 6-8-μm-thick intermetallic layer was grown at the interface. Nevertheless, tensile fracture still occurred in the heat-affected zone of the aluminum material. Electrical resistivity of the joint was smaller than resistivity of the aluminum material. Production of such composite material would result in coiled sheet material that could be subjected to further treatments such as electroplating and forming operations in an efficient and economically viable manner. The new composite material is promising for emerging automotive and industrial electrical applications.
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