Optically Tunable Magneto-Capacitance Phenomenon in Organic Semiconducting Materials Developed by Electrical Polarization of Intermolecular Charge-Transfer States

摘要

Magneto-capacitance, which can be produced by magnetically-dependent electrical polarization in functional materials, have attracted extensive interest in recent years because of their potential applications in information storage and sensing devices. Primarily, magneto-capacitance can be generated by combining magnetic and ferroelectric structures through electric-magnetic coupling based on thin-film, heterojunction, and nanostructure designs. However, in organic semiconducting materials magneto-capacitance phenomena have rarely been investigated. It is noticed that charge-trapping effects induced at the magnetic resonance condition can affect the electrical polarization shown in photocurrent-detected magnetic resonance measurements in polymer diodes. In addition, admittance spectroscopy measurements have indicated that applying a magnetic field can change the capacitance of bipolar polymer diodes when charge injection is realized under DC biases.