Humidity-dependent piezoelectric output of Al–ZnO nanowire nanogenerator and its applications as a self-powered active humidity sensor

Al-doped ZnO nanowire arrays are used to fabricate a piezoelectric nanogenerator, and its output is significantly dependent on the humidity in the environment, showing its applications as a self-powered active humidity sensor. The piezoelectric output of the device acts as both the power source and response signal to the humidity.