Gradient doped polymer nanowire for moistelectric nanogenerator

A moistelectric nanogenerator based on gradient doped polypyrrole nanowire has been fabricated by concentration-controlled electro-deposition (CCED) technique. The specially designed composition and structure of the gradient doped polypyrrole nanowire endow it with huge surface area and one-dimensional transport nanochannels, which can largely facilitate the diffusion of water molecules to generate the dissociated charged ions as free carriers. For a polypyrrole nanowire with a diameter of 200 nm, it exhibits a high-output voltage in excess of 72 mV, a remarkable output current of 0.45 nA, and a maximum output power density of 103.13 mW cm(-2) by area and 9.0 x 10(4) W kg(-1) by mass under the.RH of 75%. On this basis, a vertically aligned gradient doped polypyrrole nanowire arrays show high current output of 0.14 mu A without voltage drop. This work presents the first example that the power is gathered from moisture via polymer nanogenerators for energy-conversion application.