Surface Functionalization with Copper Tetraaminophthalocyanine Enables Efficient Charge Transport in Indium Tin Oxide Nanocrystal Thin Films

Mahdi Samadi Khoshkhoo; Santanu Maiti; Frank Schreiber; Thomas Chassé; Marcus Scheele

doi:10.1021/acsami.7b00555

Surface Functionalization with Copper Tetraaminophthalocyanine Enables Efficient Charge Transport in Indium Tin Oxide Nanocrystal Thin Films

ACS Appl Mater Interfaces. 2017 Apr 26;9(16):14197-14206. doi: 10.1021/acsami.7b00555. Epub 2017 Apr 17.

Authors

Mahdi Samadi Khoshkhoo¹, Santanu Maiti¹, Frank Schreiber¹, Thomas Chassé¹, Marcus Scheele¹

Affiliation

¹ 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.

PMID: 28398030
DOI: 10.1021/acsami.7b00555

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.

Keywords: colloidal nanocrystals; indium tin oxide (ITO); molecular electronics; nanoparticles; phthalocyanine; self-assembly; thin films; transparent electrodes.