Nonlinear potential field in contact electrification

Abstract

The cause of electron transfer in contact electrification is one of the most hotly debated physical problems today. In this study, the electron transfer is hypothesized to be partly driven by the surface dipole induced potential during contact. This phenomena is demonstrated by a combination of atomistic field theory (AFT) and molecular dynamics (MD) simulation. A representative contact system of carbon and silicon dioxide was chosen for its excellent tribo-tunneling power output performance. The results reveal the existence of a nonlinear potential field as well as the existence of a separation dependent potential barrier at the contact interface. Possible scenarios of triboelectric charge transfer are discussed in light of these results. These results are critical to the fundamental understanding of contact electrification.

Figures (7)

• Figure 1: (a) The blue atoms are silicon, the green atoms are oxygen, and the red atoms are carbon. (b) The simulation setup. The probe travels downwards at 20 m/s, until it is 5 Å above the base, then rests for 10 ps to let the system equilibrate.
• Figure 2: (a) The change in the polarization magnitude at contact, (b) The deformation along the z axis at contact
• Figure 3: The relative potential in the gap between the probe and the base. (a) shows the side view of the slice shown in (b). The dashed line in (a) is the line where the potential in Fig. \ref{['fig:1DPot']} was calculated.
• Figure 4: The relative potential along the centerline of the probe. The shaded region marks the gap between the two materials, with the position measured from the bottom of the silicon dioxide probe. (a) shows the entire material, while (b) focuses on the gap between the materials.
• Figure 5: The difference in potential between the two surfaces. The pink box outlines the carbon probe.