title: Surface Functionalization with Copper Tetraaminophthalocyanine Enables Efficient Charge Transport in Indium Tin Oxide Nanocrystal Thin Films.
abstract: Macroscopic superlattices of tin-doped indium oxide (ITO) nanocrystals (NCs) are prepared by self-assembly at the air/liquid interface followed by simultaneous ligand exchange with the organic semiconductor copper 4,4',4″,4‴-tetraaminophthalocyanine (Cu4APc). By using X-ray photoelectron spectroscopy (XPS), grazing-incidence small-angle X-ray scattering (GISAXS), and ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy, we demonstrate that the semiconductor molecules largely replace the native surfactant from the ITO NC surface and act as cross-linkers between neighboring particles. Transport measurements reveal an increase in electrical conductance by 9 orders of magnitude, suggesting that Cu4APc provides efficient electronic coupling for neighboring ITO NCs. This material provides the opportunity to study charge and spin transport through phthalocyanine monolayers.
authors.affiliation: Institute of Physical and Theoretical Chemistry, ‡Institute of Applied Physics, and §Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tübingen , 72076 Tübingen, Germany.
authors.forename: Mahdi
authors.identifier: http://orcid.org/0000-0003-0393-4768
authors.initials: M
authors.lastname: Samadi Khoshkhoo
authors.affiliation: Institute of Physical and Theoretical Chemistry, ‡Institute of Applied Physics, and §Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tübingen , 72076 Tübingen, Germany.
authors.forename: Santanu
authors.initials: S
authors.lastname: Maiti
authors.affiliation: Institute of Physical and Theoretical Chemistry, ‡Institute of Applied Physics, and §Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tübingen , 72076 Tübingen, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Schreiber
authors.affiliation: Institute of Physical and Theoretical Chemistry, ‡Institute of Applied Physics, and §Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tübingen , 72076 Tübingen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Chassé
authors.affiliation: Institute of Physical and Theoretical Chemistry, ‡Institute of Applied Physics, and §Center for Light-Matter Interaction, Sensors & Analytics LISA+, University of Tübingen , 72076 Tübingen, Germany.
authors.forename: Marcus
authors.identifier: http://orcid.org/0000-0002-2704-3591
authors.initials: M
authors.lastname: Scheele
keywords: colloidal nanocrystals; indium tin oxide (ITO); molecular electronics; nanoparticles; phthalocyanine; self-assembly; thin films; transparent electrodes