Abstract
Traditionally, magneto-dielectric effects have been developed by combining ferroelectric and magnetic materials. Here, we show a magneto-dielectric effect from optically-generated intermolecular charge-transfer states in an organic semiconducting donor:acceptor (PVK:TCNB) system. We observe in magnetic field effects of photoluminescence that a magnetic field can change singlet/triplet population ratio in intermolecular charge-transfer states. Furthermore, our theoretical analysis and experimental evidence indicate that the singlets and triplets in charge-transfer states have stronger and weaker electrical polarizations, respectively. Therefore, the observed magneto-dielectric effect can be attributed to magnetically-dependent singlet/triplet ratio in intermolecular charge-transfer states. In principle, a magneto-dielectric effect can be generated through two different channels based on magneto-polarization and magneto-current effects when the singlet/triplet ratio in intermolecular charge-transfer states is changed by a magnetic field. We find, from the simulation of dielectric effects, that magneto-polarization and magneto-current effects play primary and secondary roles in the generation of magneto-dielectric effect.
| Original language | English |
|---|---|
| Article number | 2812 |
| Journal | Scientific Reports |
| Volume | 3 |
| DOIs | |
| State | Published - 2013 |
Funding
The authors would like to acknowledge the financial supports from Air Force Office of Scientific Research (AFOSR) under the grant number FA9550-11-1-0082 and from NSF Under grant number ECCS-0644945. The authors also want to acknowledge the support from The Asian Office of Aerospace Research and Development (AOARD). This research was partially conducted at the Center for Nanophase Materials Sciences based on user project (CNMS2012-106 and CNMS2012-107), which is sponsored at Oak Ridge National Laboratory by the Division of Scientific User Facilities, U.S. Department of Energy.