Energy level alignment and interactive spin polarization at organic/ferromagnetic metal interfaces for organic spintronics

[Display omitted] •Donor-type material AOB and acceptor-type material TCNQ can tune the effective work function of Fe.•The interactive spin polarization at organic/Fe interface is investigated by XMCD technique.•The adsorptions of TCNQ and AOB have different influence on the spin polarization of Fe surface.•Detailed magnetic moment of Fe is obtained by the calculation based on XMCD sum rules.•Combination of energy level alignment and spin polarization provides a “full” analysis for the material selection. Energy level alignment and spin polarization at tetracyanoquinodimethane/Fe and acridine orange base/Fe interfaces are investigated by means of photoelectron spectroscopy and X-ray magnetic circular dichroism (XMCD), respectively, to explore their potential application in organic spintronics. Interface dipoles are observed at both hybrid interfaces, and the work function of Fe is increased by 0.7eV for the tetracyanoquinodimethane (TCNQ) case, while it is decreased by 1.2eV for the acridine orange base (AOB) case. According to XMCD results, TCNQ molecule has little influence on the spin polarization of Fe surface. In contrast, AOB molecule reduces the interfacial spin polarization of Fe significantly. Induced spin polarization of the two organic molecules at the interfaces is not observed. The results reveal the necessity of investigating the magnetic property changes of both the OSC and the FM during the process of energy level alignment engineering.