The applications of piezoelectric nanogenerators (PENGs) as a sustainable power source for portable electronic devices are still limited due to low voltage output ranging from mini- to several volts. In this study, we first develop a porous ZnO structure by annealing (650–950 °C) sputtered ZnO thin film. The porous ZnO thin film enables a significant enhancement in the output voltage of primitive PENG (up to 3 mV), i.e., by 7.5 times than that of pristine ZnO (0.4 mV). Concurrently, the introduction of pores in ZnO thin films leads to a 6.9-fold enhancement in the sensitivity of piezotronic force sensor compared to the pristine one. These excellent performances are further supported by up to two-fold enhancement in the piezoelectric coefficient (2.62 pm/V) than that of pristine ZnO (1.12 pm/V). Herein, we conducted transmission electron microscopy characterizations and found that this phenomenon can be ascribed to the lattice contraction in the c-direction induced by the pores. The diffusion-controlled pore formation mechanism is elucidated.
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