On the origin of contact-electrification

Although contact electrification (triboelectrification) (CE) has been documented since 2600 years ago, its scientific understanding remains inconclusive, unclear, and un-unified. This paper reviews the updated progress for studying the fundamental mechanism of CE using Kelvin probe force microscopy for solid–solid cases. Our conclusion is that electron transfer is the dominant mechanism for CE between solid–solid pairs. Electron transfer occurs...