Development of Al foil-based sandwich-type ZnO piezoelectric nanogenerators

This paper presents a highly cost-effective design for an aluminum (Al) foil-based ZnO/Ag/ZnO-stacked piezoelectric nanogenerator (ZAZ-NG) fabricated using radio frequency magnetron sputtering. Both Al foil sheets and a silver (Ag) paste layer are utilized to make a ZAZ-NG composed of an Ag paste layer sandwiched between two zinc oxide (ZnO) layers. The output voltages of the ZAZ-NGs with various ZnO thicknesses are measured for three different bending strains. As a result, the devices could generate a relatively high peak-to-peak output voltage (Vpp) of up to 2.5 V, which is 28 times higher than that of the single ZnO layered device. In addition, the device performance shows a strong dependence on the thickness of the ZnO layer. Moreover, the ZAG-NG device is structurally stable and can be fabricated using cost-effective methods.