TY - JOUR A1 - Joshi, Siddharth A1 - Pingel, Patrick A1 - Grigorian, Souren A1 - Panzner, Tobias A1 - Pietsch, Ullrich A1 - Neher, Dieter A1 - Forster, Michael A1 - Scherf, Ullrich T1 - Bimodal temperature behavior of structure and mobility in high molecular weight p3ht thin films N2 - We report a temperature dependent crystalline structure of spin-coated thin films of high molecular weight regioregular poly(3-hexylthiophene) (P3HT) (M-n similar to 30000 g/mol) and its correlation with charge carrier mobility. These investigations show a reversible change of the crystalline structure, where the interlayer lattice spacing (100)along the alkyl side chains continuously increases up to a temperature of about 220 degrees C; in contrast, the in-plane pi-pi distance reduces with increasing temperature. These changes in structure are reversible and can be repeated several times. The temperature-induced structural properties differ for thick and thin films, pointing to a surface/interface role in stabilization of the layer morphology. In contrast to the structural changes, the carrier mobility is rather constant in the temperature range from room temperature up to 100-120 degrees C, followed by a continuous decrease. For thick layers this drop is significant and the transistor performance almost vanishes at high temperature, however, it completely recovers upon cooling back to roorn temperature. The drop of the charge carrier mobility at higher temperatures is in contrast with expectations front the structural studies, considering the increase of crystalline fraction of the polycrystalline layer. our electrical measurements Underscore that the reduction of the macroscopic mobility is mostly caused by it pronounced decrease of the intergrain transport. The thermally induced crystallization along(100) direction and the creation of numerous small crystallites at the film-substrate interface reduce the number of long polymer chain, bridging crystalline domains, which ultimately limits the macroscopic charge transport. Y1 - 2009 UR - http://pubs.acs.org/journal/mamobx U6 - https://doi.org/10.1021/Ma900021w SN - 0024-9297 ER - TY - JOUR A1 - Send, Sebastian A1 - von Kozierowski, Marc A1 - Panzner, Tobias A1 - Gorfman, Semen A1 - Nurdan, Kivanc A1 - Walenta, Albert H. A1 - Pietsch, Ullrich A1 - Leitenberger, Wolfram A1 - Hartmann, Robert A1 - Strüder, Lothar T1 - Energy-dispersive Laue diffraction by means of a frame-store pnCCD Y1 - 2009 UR - http://journals.iucr.org/j/journalhomepage.html U6 - https://doi.org/10.1107/S0021889809039867 SN - 0021-8898 ER - TY - JOUR A1 - Reinhold, Beate A1 - Geue, Thomas A1 - Huber, Patrick A1 - Sant, Tushar A1 - Pietsch, Ullrich A1 - Sztucki, Michael T1 - In situ and ex situ SAXS investigation of colloidal sedimentation onto laterally patterned support N2 - We report on in situ investigations of colloidal ordering during gravity sedimentation from a colloidal suspension onto a prepatterned support using a polymeric surface relief grating (SRG) as the support. The ordering of colloids with a diameter of 420 nm was investigated by means of grazing-incidence small-angle X-ray scattering (GISAXS) and transmission SAXS using a preparation cell guaranteeing stable temperature and humidity. GISAXS was used for in situ monitoring of the time evolution of colloidal ordering within the whole illuminated sample area. The onset of ordering was indicated by the increase of integrated intensity within a small time frame shortly before complete evaporation of the dispersant. Single domains of coated samples were investigated ex situ by SAXS in transmission geometry where the irradiated sample area was 200 x 200 mu m(2) only. Domains with the typical size of a few millimeters were observed varying in orientation and crystallographic structure for various positions at the sample. They were mainly oriented along the grooves of the grating, confirming the influence of the underlying grating on colloidal ordering. Y1 - 2009 UR - http://pubs.acs.org/journal/langd5 U6 - https://doi.org/10.1021/La803078b SN - 0743-7463 ER - TY - JOUR A1 - Reddy, Raghavendra V. A1 - Gupta, Ajay A1 - Gome, Anil A1 - Leitenberger, Wolfram A1 - Pietsch, Ullrich T1 - In situ x-ray reflectivity and grazing incidence x-ray diffraction study of L1(0) ordering in Fe-57/Pt multilayers N2 - In situ high temperature x-ray reflectivity and grazing incidence x-ray diffraction measurements in the energy dispersive mode are used to study the ordered face-centered tetragonal (fct) L1(0) phase formation in [Fe(19 angstrom)/ Pt(25 angstrom)](x10) multilayers prepared by ion beam sputtering. With the in situ x-ray measurements it is observed that (i) the multilayer structure first transforms to a disordered FePt and subsequently to an ordered fct L1(0) phase, (ii) the ordered fct L1(0) FePt peaks start to appear at 320°C annealing, (iii) the activation energy of the interdiffusion is 0.8 eV and (iv) ordered fct FePt grains have preferential out-of-plane texture. The magneto-optical Kerr effect and conversion electron Mossbauer spectroscopies are used to study the magnetic properties of the as- deposited and 400°C annealed multilayers. The magnetic data for the 400°C annealed sample indicate that the magnetization is at an angle of ~50° from the plane of the film. Y1 - 2009 UR - http://iopscience.iop.org/0953-8984 U6 - https://doi.org/10.1088/0953-8984/21/18/186002 SN - 0953-8984 ER -