Room-temperature organic magnetoresistance based on interfacial ground charge transfer state

Abstract

We propose an organic magnetoresistance (OMR) based on the weak interfacial ground charge transfer (IGCT) state at m-MTDATA/Alq3 heterojunction. The maximum OMR reaches 13.2% at room temperature under an external magnetic field of 300 mT, which is well interpreted by the different roles of singlet and triplet IGCT states in hole transport. As demonstrated, the hole transport is blocked by singlet IGCT and passed through by triplet IGCT. By manipulating the Larmor frequencies of mixing singlet and triplet IGCT states through Δg mechanism under an external magnetic field, the hole current is modulated, thus generating OMR. Furthermore, OMR can be further enhanced to 15.4% at 300 mT and 27.9% at 1000 mT by inserting a thin BCP interlayer between m-MTDATA and Alq3 layers. This picture will help to implement a giant OMR with interfacial CT states in the future.