title: Thermally induced solid-state phase transition of bis(triisopropylsilylethynyl) pentacene crystals.
abstract: Bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) is a functionalized pentacene derivative designed to enhance both the solution solubility and solid-state packing of pentacene. In this paper, we report our observations of a solid-state phase transition in TIPS pentacene crystals upon heating or cooling. Evidence from differential scanning calorimetry (DSC), hot-stage optical microscopy, as well as high-temperature X-ray and electron diffraction are presented. A reasonable match with experimental data is obtained with molecular modeling. Our results reveal that the transition is associated with a conformational reorganization of the TIPS side groups, accompanied by a slight decrease in the acene-to-acene spacing and a shift of the overlap between the neighboring pentacene units. The observed cracking should be avoided or minimized in TIPS pentacene-based thin film transistors to maintain their relatively high charge carrier mobility.
authors.affiliation: Macromolecular Science and Engineering, Materials Science and Engineering, Biomedical Engineering, The University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, USA.
authors.forename: Jihua
authors.initials: J
authors.lastname: Chen
authors.forename: John
authors.initials: J
authors.lastname: Anthony
authors.forename: David C
authors.initials: DC
authors.lastname: Martin
mesh_terms: D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D008956:Models, Chemical; D015394:Molecular Structure; D017646:Organosilicon Compounds / Q000737:chemistry*; D044367:Phase Transition; D013696:Temperature
chemical_list: D017646:Organosilicon Compounds; C522282:bis(triisopropylsilylethynyl)pentacene