Multi-dimensional, transparent and foldable cellulose-based triboelectric nanogenerator for touching password recognition

Transparent power sources are required for emerging electronics and energy devices. However, most transparent materials/systems present certain problems: they are often fragile and unsuitable for shaping into fixed three-dimensional structures. Here, we attempted to overcome these challenges by constructing a cellulose-based multilayer film as a single-electrode triboelectric nanogenerator (TENG). The TENG was simply fabricated by the step-by-step deposition of a cellulose triboelectric layer, a silver nanowire electrode layer, and a protective cellulose layer. The tightly packed thin film is transparent, flexible and foldable. Four TENGs were spontaneously assembled into one film, and various spatial configurations were generated by a series of cutting and folding processes. We proved the practicality of a TENG-containing cellulose-based multilayer film by developing a multi-dimensional touch password switch, and expect that it will be widely used in film-based intelligent electronics.