Biomolecule-adsorption-dependent piezoelectric output of ZnO nanowire nanogenerator and its application as self-powered active biosensor

Self-powered active biosensor has been realized from ZnO nanowire (NW) nanogenerator (NG). The piezoelectric output generated by ZnO NW NG can act not only as a power source for driving the device, but also as a biosensing signal. After immersing in 10−3gml−1 human immunoglobulin G (IgG), the piezoelectric output voltage of the device under compressive deformation decreases from 0.203±0.0176V (without IgG) to 0.038±0.0035V. Such a self-powered biosensor has higher response than transistor-type biosensor (I–V behavior). The response of self-powered biosensor is in a linear relationship with IgG concentration (logarithm, 10−7–10−3gml−1) and the limit of detection (LOD) on IgG of the device is about 6.9ngml−1. The adsorption of biomolecules on the surface of ZnO NWs can modify the free-carrier density, which vary the screening effect of free-carriers on the piezoelectric output. The present results demonstrate a feasible approach for actively detecting biomolecules by coupling the piezotronic and biosensing characteristics of ZnO NWs. •New self-powered active biosensor has been realized without external electric power.•The piezoelectric output of ZnO NWs acts as both energy source and biosensing signal.•The sensitivity is much higher than the traditional biosensor (I–V behavior).•It opens a new direction for the development self-powered active biosensors.