Magnetic Nanofilm of Fe3O4 for Highly Efficient Organic Light-Emitting Devices

We have demonstrated enhanced efficiency from organic light-emitting devices (OLEDs) with Fe3O4-coated indium tin oxide (ITO) anodes The current efficiency of the OLEDs with Fe3O4/ITO anode is increased by 10 5%, when an external magnetic field is applied. This improvement is ascribed to the magnetic field-induced spin polarization of holes injected through the spin aligner of the Fe3O4 film, which results in an enhanced formation ratio of singlet excitons. In addition, Fe3O4 is also found acting as an anodic buffer to increase the hole-injection efficiency. The improved luminance and efficiency considered as resulting from the anode interfacial modification of Fe3O4 compared to the devices with bare ITO