Indexation scheme for oriented molecular thin films studied with grazing-incidence reciprocal-space mapping

Abstract

Thin films of small molecules relevant to organic electronics applications often show a confusing degree of polymorphism. An effective reciprocal-space mapping scheme has been developed in order to find and index thin-film reflections which are related to previously known molecular structures. By method of elimination, thin-film reflections due to novel thin-film phases can thus be identified.

Donor‐Acceptor Interfacial Interactions Dominate Device Performance in Hybrid P3HT‐ZnO Nanowire‐Array Solar Cells

“…The beam was selected to be 0.05 mm tall and 1 mm wide. The width of the samples was 0.5 cm; this smaller sample width was chosen to reduce geometric smearing of crystalline reflections . The beam energy was selected with synthetic multilayer optics (W/B4C, 23.6 Å d ‐spacing).…”

Indexing of grazing-incidence X-ray diffraction patterns: the case of fibre-textured thin films

“…Crystal structure solutions from GIXD require the indexing of the diffraction pattern, that is, the assignment of Laue indices to the observed Bragg peaks. In our specific case of GIXD on fibre-textured films, two components of the reciprocal-lattice vectors -namely q z and q xy -are available for the indexing process (Smilgies & Blasini, 2007;Hailey et al, 2014). This is considerably different to the indexing procedure employed for single-crystal diffraction patterns, where all three components of reciprocal-lattice vectors are recorded, as well as for powder diffraction of polycrystalline materials, where only the lengths of the scattering vectors are detected.…”

“…Few programs have yet been developed for the indexing of two-dimensional reciprocal-space maps (Smilgies & Blasini, 2007;Breiby et al, 2008;Hailey et al, 2014;Jiang, 2015). Certainly, the situation is relatively trivial if all lattice parameters are known.…”

“…A further input parameter for the indexing arises from specular X-ray diffraction experiments, as in essentially all cases of crystalline organic thin films grown in a fibre texture one defined Bragg peak (or one Bragg peak series) is observed at q spec , originating from the plane normal to the fibre axis of the film. This peak (series) is due to diffraction from the contact plane of the fibre-textured film, which is assigned to a crystallographic plane of Miller indices u, v and w (Salzmann & Resel, 2004;Smilgies & Blasini, 2007;Hailey et al, 2014;Jiang, 2015). By combining the peak posi- (a) Geometry of a grazing-incidence X-ray diffraction (GIXD) experiment with k 0 and k representing the wavevectors of the primary and of the scattered X-ray beam, respectively, together with the corresponding angle of incidence i , the in-plane scattering angle f and the out-of-plane scattering angle f .…”

Controlling Polymorphism in Pharmaceutical Compounds Using Solution Shearing

“…The 2D data was analyzed using the indexGIXS software package developed by Detlef Smilgies. 38 Fit2d was used to integrate 2D diffraction images to the 1D analog along constant radius from the beam center. 39 Mercury was used to produce simulated powder patterns from deposited crystallographic information (cif) files in the Cambridge structure database from previous studies.…”