Abstract
Using vertically grown hydrothermal ZnO nanowires, we demonstrate the assembly of fully functional piezoelectric energy harvesters on plastics substrates. A seedless hydrothermal process is employed for the growth of single crystalline vertically orientated ZnO NWs at around 100oC. Flexible NG are assembled using ∼7 μm thick PDMS polymer matrix on a 3x3cm substrate. A representative device with an active area of 4cm2 is characterised revealing average output voltage generation of ∼22mV (±1.2) and -32mV (±0.16) in the positive and negative cycles after 3-4mm periodic deflection at 20Hz. A power density of ∼288nW/cm3 is estimated for the device. It is envisaged that such energy scavengers may find potential applications targeting self-powered systems, sensors and on-body charging of electronics.