title: Oriented thin films of a benzodithiophene covalent organic framework.
abstract: A mesoporous electron-donor covalent organic framework based on a benzodithiophene core, BDT-COF, was obtained through condensation of a benzodithiophene-containing diboronic acid and hexahydroxytriphenylene (HHTP). BDT-COF is a highly porous, crystalline, and thermally stable material, which can be handled in air. Highly porous, crystalline oriented thin BDT-COF films were synthesized from solution on different polycrystalline surfaces, indicating the generality of the synthetic strategy. The favorable orientation, crystallinity, porosity, and the growth mode of the thin BDT-COF films were studied by means of X-ray diffraction (XRD), 2D grazing incidence diffraction (GID), transmission and scanning electron microscopy (TEM, SEM), and krypton sorption. The highly porous thin BDT-COF films were infiltrated with soluble fullerene derivatives, such as [6,6]-phenyl C61 butyric acid methyl ester (PCBM), to obtain an interpenetrated electron-donor/acceptor host-guest system. Light-induced charge transfer from the BDT-framework to PCBM acceptor molecules was indicated by efficient photoluminescence quenching. Moreover, we monitored the dynamics of photogenerated hole-polarons via transient absorption spectroscopy. This work represents a combined study of the structural and optical properties of highly oriented mesoporous thin COF films serving as host for the generation of periodic interpenetrated electron-donor and electron-acceptor systems.
authors.affiliation: Department of Chemistry and Center for NanoScience (CeNS), University of Munich (LMU) , Butenandtstrasse 5-13, Haus E, 81377 München, Germany.
authors.forename: Dana D
authors.initials: DD
authors.lastname: Medina
authors.forename: Veronika
authors.initials: V
authors.lastname: Werner
authors.forename: Florian
authors.initials: F
authors.lastname: Auras
authors.forename: Raphael
authors.initials: R
authors.lastname: Tautz
authors.forename: Mirjam
authors.initials: M
authors.lastname: Dogru
authors.forename: Jörg
authors.initials: J
authors.lastname: Schuster
authors.forename: Stephanie
authors.initials: S
authors.lastname: Linke
authors.forename: Markus
authors.initials: M
authors.lastname: Döblinger
authors.forename: Jochen
authors.initials: J
authors.lastname: Feldmann
authors.forename: Paul
authors.initials: P
authors.lastname: Knochel
authors.forename: Thomas
authors.initials: T
authors.lastname: Bein