The role of electron-hole recombination in organic magnetoresistance

Abstract

Magneto-electrical measurements were performed on diodes and bulk heterojunction solar cells (BHSCs) to clarify the role of formation of coulombically bound electron-hole (e-h) pairs on the magnetoresistance (MR) response in organic thin film devices. BHSCs are suitable model systems because they effectively quench excitons but the probability of forming e-h pairs in them can be tuned over orders of magnitude by the choice of material and solvent in the blend. We have systematically varied the e-h recombination coefficients, which are directly proportional to the probability for the charge carriers to meet in space, and found that a reduced probability of electrons and holes meeting in space lead to disappearance of the MR. Our results clearly show that MR is a direct consequence of e-h pair formation. We also found that the MR line shape follows a power law-dependence of B0.5 at higher fields.

References in corpus (2)

• Large magnetoresistance in $\pi$-conjugated semiconductor thin film devices
• Large magnetoresistance at room-temperature in semiconducting polymer sandwich devices

Cited by in corpus (5)

• Magnetic field effects on electron-hole recombination in disordered organic semiconductors
• Hysteretic magnetoresistance in polymeric diodes
• A theory for magnetic-field effects of nonmagnetic organic semiconducting materials
• Towards printed magnetic sensors based on organic diodes
• Origin and the role of device physics in the magnetic field effect in organic semiconductor devices