Semiconductor Contact-Electrification-Dominated Tribovoltaic Effect for Ultrahigh Power Generation.

The semiconductor direct-current triboelectric nanogenerator (SDC-TENG) based on the tribovoltaic effect is promising for developing a new semiconductor energy technology with high power density. Here, the first SDC-TENG built using gallium nitride (GaN) and bismuth telluride (Bi2 Te3 ) for ultrahigh-power generation is reported. During the friction process, an additional interfacial electric field is formed by continuous contact electrification (CE), and abundant electron-hole pairs are excited and move directionally to form a junction current that is always internally from Bi2 Te3 to GaN, regardless of the semiconductor type. The peak open-circuit voltage can reach up to 40 V and the power density is 11.85 W m-2 (average value is 9.23 W m-2 ), which is approximately 200 times higher than that of previous centimeter-level SDC-TENGs. Moreover, compared to traditional polymer TENGs under the same conditions, the average power density is remarkably improved by over 40 times. This study provides the first evidence of CE on the tribovoltaic effect and sets the normalized power density record for TENGs, which demonstrates a great potential of the tribovoltaic effect for energy harvesting and sensing.