Charge-Transfer Induced Magnetic Field Effects of Nano-Carbon Heterojunctions

Abstract

Room temperature magnetic field effects have not been definitively observed in either single-walled carbon nanotubes (SWCNTs) or C60 under a small magnetic field due to their weak hyperfine interaction and slight difference of g-factor between positive and negative polarons. Here, we demonstrate charge-transfer induced magnetic field effects in nano-carbon C60-SWCNT bulk heterojunctions at room temperature, where the mechanism of magnetic field effects is verified using excited state transition modeling. By controlling SWCNT concentrations and interfacial interactions, nano-carbon heterojunctions exhibit tunability of charge-transfer density and room temperature magnetoconductance of 2.8% under 100 mT external magnetic field. External stimuli, such as electric field and photoexcitation, also play an important role in controlling the magnetic field effects of nano-carbon heterojunctions, which suggests that these findings could enable the control of optoelectronic properties of nano-carbon heterojunctions.

Trap effect of triplet excitons on magnetoresistance in organic devices

“…Their work revealed that population mixing due to resonant excitation causes a net change in the exciton-polaron reaction rate [29]. Also, Qin et al investigated the magnetic field effect through calculation of magnetic field dependent singlet and triplet ratios [30][31][32]. These indicated the importance of excitons in organic magnetic field effect from either experimental or theoretical aspects.…”

A Free‐Standing Molecular Spin–Charge Converter for Ubiquitous Magnetic‐Energy Harvesting and Sensing

“…An intriguing question is whether intermolecular radicals and excitation processes play an important role for magnetic‐energy harvesting in BCCT materials . Magnetic‐field effects are critical to reveal and elucidate charge‐transfer controlled intermolecular radicals and excited processes in BCCTs, where the external magnetic field can induce the spin mixing of singlet and triplet CT, and leads to the change of polarons and triplet excitons . The BCCTs exhibit magnetic‐field‐dependent capacitance in which the magnetic field and capacitance oscillate in phase ( Figure a) .…”

Optically Controlled Magnetization and Magnetoelectric Effect in Organic Multiferroic Heterojunction

“…With increasing incident light intensity (355 nm), more electron–hole pairs are generated in perovskite layer. External magnetic field could increase the ratio of triplet electron–hole pair . Because dissociation rate of singlet state is smaller than that of triplet, carrier density becomes larger under external magnetic field.…”