Charge transfer, band-like transport, and magnetic ions at F16CoPc/rubrene interfaces

TL;DR

This study investigates F16CoPc/rubrene interfaces, demonstrating enhanced conductivity, band-like transport, and magnetic interactions involving Co ions, advancing understanding of organic charge transfer systems with magnetic properties.

Contribution

It presents the first detailed analysis of charge transfer in F16CoPc/rubrene, linking electronic transport with magnetic ion involvement at the interface.

Findings

Charge transfer enhances electrical conductivity.

Band-like transport occurs in rubrene at the interface.

Charge transfer involves magnetic Co ions, affecting their spin.

Abstract

Organic semiconductors offer an unprecedented flexibility to control the electronic state of interfacial electronic systems. Here we present a first step in realizing organic charge transfer interfaces that combine both a large electrical conductivity and the presence of magnetic ions. We have performed a detailed investigation of F16CoPc/rubrene interface by means of temperature dependent charge transport measurements, Hall effect, scanning Kelvin probe microscopy and photoelectron spectroscopy. Our finding is that the charge transfer leads to significantly enhanced electrical conductivity and the band-like transport. We have determined the density, mobility and nature of charge carriers in the system (holes in rubrene). We have also found that the amount of charge transfer in F16CoPc/rubrene is high enough to cause the band-like transport in rubrene crystals at the interface. Finally, our XPS and UPS measurements have shown that the charge transfer in F16CoPc/rubrene involves electronic orbitals centered on the magnetic Co ions of the phthalocyanine molecules causing a change in their spin. Thus, F16CoPc/rubrene is the first organic interface where the charge transfer responsible for the interfacial conductivity fully involves the metal Co core of the phthalocyanine molecules, providing a link between charge transport and magnetic properties.