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Disordered lithium-rich transition metal oxyfluorides with a general formula Li$_{1+x}$MO$_{2}$F$_{x}$ (M being a transition metal) are gaining more attention due to their high specific capacity which can be delivered from the facecentered cubic (fcc) structure. The most common synthesis procedure involves use of mechanosynthesis. In this work, ceramic synthesis of lithium rich iron oxyfluoride and lithium rich titanium oxyfluoride are reported. Two ceramic synthesis routes are developed each leading to the different level of doping with Li and F and different levels of cationic disorder in the structure. Three different Li$_{1+x}$MO$_{2}$F$_{x}$ samples (x ¼ 0.25, 0.3 and 1) are compared with a sample prepared by mechanochemical synthesis and non-doped LiFeO2 with fcc structure. The obtained lithium rich iron oxyfluoride are characterized by use of M€ossbauer spectroscopy, X-ray absorption spectroscopy, NMR and TEM. Successful incorporation of Li and F have been confirmed and specific capacity that can be obtained from the samples is in the correlation with the level of disorder introduced with doping, nevertheless oxidation state of iron in all samples is very similar. Conclusions obtained from lithium rich iron oxyfluoride are validated by lithium rich titanium oxyfluoride.

Control of multi-martensite phase transformations and physical properties constitute greatly unresolved challenges in Fe7Pd3-based ferromagnetic shape memory alloys. Single crystalline Fe7Pd3 thin films reveal an austenite to martensite phase transformation, continuously ranging from the facecentered cubic (fcc) to the face-centered tetragonal (fct) and body-centered cubic (bcc) phases upon irradiation with 1.8 MeV Kr+ ions. Within the present contribution, we explore this scenario within a comprehensive experimental study: employing atomic force microscopy (AFM) and high resolution transmission electron microscopy (HR-TEM), we first clarify the crystallography of the ionirradiation-induced austenite⇒martensite and inter-martensite transitions, explore the multivariant martensite structures with c-a twinning and unravel a very gradual transition between variants at twin boundaries. Accompanying magnetic properties, addressed locally and globally, are characterized by an increasing saturation magnetization from fcc to bcc, while coercivity and remanence are demonstrated to be governed by magnetocrystalline anisotropy and ion-irradiationinduced defect density, respectively. Based on reversibility of ion-irradiation-induced materials changes due to annealing treatment and a conversion electron Mößbauer spectroscopy (CEMS) study to address changes in order, a quantitative defect-based physical picture of ion-irradiation-induced austenite⇔martensite transformation in Fe7Pd3 is developed. The presented concepts thus pave the way for ion-irradiation-assisted optimization strategies for tailored functional alloys.

The response of the structure of the M-type barium hexaferrite (BaFe12O19) to mechanical action through high-energy milling and its impact on the magnetic behaviour of the ferrite are investigated. Due to the ability of the Fe-57 Mossbauer spectroscopic technique to probe the environment of the Fe nuclei, a valuable insight on a local atomic scale into the mechanically induced changes in the hexagonal structure of the material is obtained. It is revealed that the milling of BaFe12O19 results in the deformation of its constituent polyhedra (FeO6 octahedra, FeO4 tetrahedra and FeO5 triangular bi-pyramids) as well as in the mechanically triggered transition of the Fe3+ cations from the regular 12k octahedral sites into the interstitial positions provided by the magnetoplumbite structure. The response of the hexaferrite to the mechanical treatment is found to be accompanied by the formation of a non-uniform nanostructure consisting of an ordered crystallite surrounded/separated by a structurally disordered surface shell/interface region. The distorted polyhedra and the non-equilibrium cation distribution are found to be confined to the amorphous near-surface layers of the ferrite nanoparticles with the thickness extending up to about 2 nm. The information on the mechanically induced short-range structural disorder in BaFe12O19 is complemented by an investigation of its magnetic behaviour on a macroscopic scale. It is demonstrated that the milled ferrite nanoparticles exhibit a pure superparamagnetism at room temperature. As a consequence of the far-from-equilibrium structural disorder in the surface shell of the nanoparticles, the mechanically treated BaFe12O19 exhibits a reduced magnetization and an enhanced coercivity. DFG/SPP/1415 APVV/0528-11 VEGA/2/0097/14

27th European Photovoltaic Solar Energy Conference and Exhibition; 2276-2280, Within the last few years, the development of thin film CIGS solar cells made significant progress. A compelling part of the increase in efficiency of CIGS solar cells came through developments and improvements made in the coating technology. Despite its importance, the coating for the cell and module cannot stand alone to ameliorate its overall properties. At the end, the best product will consist of a synergy of all involved process methods. Today, we still observe that structuring of the cells is done with needles, which scrape away the layer by breaking out parts of the coating. This process is subject to wear and tear, and achievable results will limit the development of higher efficiency panels in the near future. While the processes for pattern one (P1), the structuring of molybdenum (Mo), are commonly done by means of a laser beam, scribing processes for pattern two and three (P2, P3) are not so far advanced. Two main reasons can be made responsible for this lack of progress. First, there is the difference how the laser beam is applied. Contrary to other thin film processes, the beam cannot be applied through the substrate since the Mo layer is blocking it. Secondly, the material properties of the chalcopyrite copper indium gallium (di)selenide (CIGS; Cu(In,Ga)(S,Se)2), which is at first brittle and tends, when exposed to heat, to build copper-rich, conductive phases. In an earlier work [11, 12] investigating a basic setting for an all laser CIGS scribing process a variety of possibilities was found to process P2. In this paper, we will further investigate the possibilities for the laser based CIGS scribing process.

26th European Photovoltaic Solar Energy Conference and Exhibition; 2718-2723, In a continuously growing solar photo voltaic market with both, crystalline silicon (c-Si) as well as thin-film technology, the continuous growth is directly dependent on the manufacturing costs for solar cells. The key factors for cost reduction are innovative ideas to optimize precision and throughput. Lasers are excellent tools to provide highly efficient processes with impressive accuracy. They can excel best in combination with fast and precise motion systems for a maximum gain in the manufacturing process, yielding best cost of ownership. With this work an industrial tool is presented that combines a series of unique and innovative solutions for thinfilm scribing. The combination of a new substrate holding technique on a machine with a fast and precise motion system is the base for a cost effective scribing machine. With the vacuum glass holding technique it is possible to gain a tighter tolerance range, making the process more stable to fluctuations in the substrate thickness and therefore increasing the process window significantly. This is further supported by the fact that the substrate is fixed throughout the whole scribing process to reduce vibration induced issues. Utilizing new laser sources with fiber guided beam delivery can reduce the weight on the accelerated parts and is permitting high-speed processing up to 2000 mm/sec while keeping the beam quality at a M2 below 1.5. A further improvement that comes with fiber guided lasers is the short beam path in the working head, reducing the alignment and set-up time to a fraction that is currently the case for laser scribing systems. All the above mentioned improvements are influencing the production time and reliability. To improve the module efficiency directly through the laser scribing process one way to go is to reduce the dead zone. Utilizing the high precision of the system a module with a dead zone of sub 100m is demonstrated bringing all the advantages to bear. Also an outlook is given on the possible impact on cell efficiency, manufacturing costs, and cost of ownership implementing such a concept into production.

26th European Photovoltaic Solar Energy Conference and Exhibition; 2986-2991, The thin film (TF) solar market is challenged to produce solar modules with higher energy conversion efficiency while at the same time reducing the manufacturing cost. One way to improve the energy efficiency is to move to higher performance systems like Cadmiumtellurid (CdTe) or Cu(In,Ga)(S,Se)2 (CIGS) in comparison to TF Silicon (Si) based technologies. As today’s a-Si and CdTe structuring technology for module development is based on laser scribing, the technology for CIGS modules is mostly dominated by mechanical scribing. As inexpensive as the mechanical scribing technology seems, it has its drawbacks when it comes to high precision scribing of TF materials and, subsequently, the reliability in the manufacturing process. Bringing together a high speed, high accuracy motion system with ultra short pulse laser sources opens up new ways CIGS solar cell production can be perceived. We present with this work an in depth evaluation of the influences of the laser pulse width and wavelength to the CIGS scribing process on glass substrate. A variation of the pulse width in the range of 10 ps to 100 ps and 1 ns up to 30 ns is studied and monitored to determine the influences on the scribing quality. At the end, a functional mini-module is presented featuring a dead zone of less than 200 μm. Incorporating the results into a scribing tool an innovative industrial concept is developed for future integration. An outlook is given on the possible impact on cell efficiency, manufacturing costs, and cost of ownership implementing such a concept into production.