Fig. 1: .

Concept, structure and working mechanism of the silk fibroin-based triboelectric system. a Photo of a flexible and biocompatible SFB-TENG. b Working mechanism of the four stages of charge transfer in the SFB-TENG. c Typical structure of the SFB-TENG. d Schematic diagram of the SFB-TENG with a micropillar array. e SEM image of the micropillar array. The dimensions are 30 µm in diameter and 180 µm in height