Use of a hexapod in diffraction measurements of substrate-supported crystals of organic semiconductors

摘要

Thin films of organic semiconductor prepared on substrates generally containcrystals that have one common crystal plane parallel to the substrate but randomin-plane orientations. In diffraction measurements of these structures, it is oftenrequired to anchor the X-ray beam on a fixed spot on the sample, such as anoptically visible crystallite or island. Here, a hexapod is used in place of atraditional multi-circle diffractometer to perform area-detector-based diffrac-tion measurements on an actual device that contains 6,13-bis(triisopropyl-silyethynyl)-pentacene (TIPS-pentacene) crystals. The hexapod allows forsample rotations about any user-defined rotation center. Two types of complexsample motions have been programmed to characterize the structure of theTIPS-pentacene crystal: an in-plane powder average has been performed at afixed grazing-incident angle to determine the lattice parameters of the crystal;then the in-plane component of the scattering vector was continuously rotated intransmission geometry to determine the local crystal orientation.