Measuring Triboelectric Energy Conversion in Leaves of Living Plants

Contact electrification or triboelectric charging is a long-known ubiquitous phenomenon which occurs on almost all material surfaces. It comprises the generation of longer- or shorter-lived static charges on the surface of a material upon contact with another material. The classical example is the charging of hairs with a rubber balloon. The effect is receiving increased attention as a possible mechanism to convert mechanical energy into electricity for energy harvesting. It is required that an electrode is installed near the charged surface (often a dielectric polymer) into which the generated charges can be electrostatically induced. Multiple artificial energy harvesters have been developed in the last decade to exploit this mechanism. Interestingly, also in nature, configurations exist that allow structures to convert mechanical energy into electricity by the triboelectric effect. These are especially the leaves of all living plants. Indeed, living plants have recently been used as triboelectric energy converters and for harvesting energy from leaf motion in the wind [1]–[5]. Here, we describe in detail how to measure triboelectric charges in the tissue of living plants, the particularities of measuring such signals in the organisms, and what is essential when using them for energy harvesting.