Spin-selected electron transfer in liquid-solid contact electrification

Electron transfer has been shown to contribute to contact electrification at liquid-solid interface. Here, authors investigate the magnetic field effect on the liquid-solid electron transfer and propose a spin conversion model for the liquid-solid contact electrification. Electron transfer has been proven the dominant charge carrier during contact electrification at the liquid-solid interface. However, the effect of electron spin in contact electrification remains to be investigated. This study examines the charge transfer between different liquids and ferrimagnetic solids in a magnetic field, focusing on the contribution of O-2 molecules to the liquid-solid contact electrification. The findings reveal that magnetic fields promote electron transfer at the O-2-containing liquid-solid interfaces. Moreover, magnetic field-induced electron transfer increases at higher O-2 concentrations in the liquids and decreases at elevated temperatures. The results indicate spin-selected electron transfer at liquid-solid interface. External magnetic fields can modulate the spin conversion of the radical pairs at the O-2-containing liquid and ferrimagnetic solid interfaces due to the Zeeman interaction, promoting electron transfer. A spin-selected electron transfer model for liquid-solid contact electrification is further proposed based on the radical pair mechanism, in which the HO2 molecules and the free unpaired electrons from the ferrimagnetic solids are considered radical pairs. The spin conversion of the [HO2 center dot center dot e(-)] pairs is affected by magnetic fields, rendering the electron transfer magnetic field-sensitive.

Automated summary

The study investigates the magnetic field effect on electron transfer at the liquid-solid interface during contact electrification and proposes a spin conversion model. The results show that magnetic fields can promote electron transfer at O-2-containing liquid-solid interfaces, with higher concentrations of O-2 in the liquids increasing the effect and elevated temperatures decreasing it. The findings highlight the importance of considering electron spin in contact electrification and provide insights into the mechanism of liquid-solid contact electrification.