Piezoelectric nanogenerator based on a flexible carbon-fiber/ZnO–ZnSe bilayer structure wire

•The pin-shaped ZnO–ZnSe nanowire arrays on the surface of a carbon fiber were synthesized via two-step hydrothermal method.•The nanogenerator device produced high-output current about 333μA.•The output current can be further enhanced by 66%. The pin-shaped ZnO–ZnSe nanowire arrays on the surface of a carbon fiber (CF/ZnO–ZnSe) were synthesized via two-step hydrothermal method. Based on a single CF/ZnO–ZnSe on a polymer substrate, a flexible nanogenerator device was fabricated which produced high-output current about 333μA when the device was subjected to a −0.55% tensile strain and the current was enhanced by as much as 66%. The superior piezoelectric performance is derived from the piezopotential in ZnO nanowire arrays induced by the compressive strain or tensile strain, which lowers or raises the barrier height and increases or decreases the current density at the ZnO–ZnSe heterojunction interface. This kind of CF/ZnO–ZnSe bilayer structure has a great potential for nanogenerator device and this result opens up the path for practical applications of piezoelectric nanogenerator.