Approach for Enhancement in Output Performance of Randomly Oriented ZnSnO₃ Nanorod-Based Piezoelectric Nanogenerator via p–n Heterojunction and Surface Passivation Layer

Abstract

Piezoelectric nanogenerators (PENGs) based on zinc stannate nanoparticles (ZnSnO3 NPs) have attracted significant attention in the field of viable energy source and self-powered sensing devices. But the output performance of ZnSnO3-based nanogenerators is considerably low as its piezoelectric potential suffers the screening of piezoelectric potential due to the presence of huge additional electrons in ZnSnO3 NPs. In this report, we put forward a facile and useful technique to enhance the performance of ZnSnO3 nanorods (NRs)-based PENG by developing a CuO/ZnSnO3 p–n junction. The holes in the CuO extraordinarily reduces the free electrons in ZnSnO3 NRs through the formation of a depletion region in between p-CuO and n-ZnSnO3 NRs. Furthermore, with spin coating of poly(dimethylsiloxane)-reduced graphene oxide (PDMS-RGO) on the CuO/ZnSnO3 layer, maximum output voltage and current of ∼27 V and ∼0.9 μA are obtained, which are about ∼5.6 and 6 times higher than those of the Cu/ZnSnO3/PDMS-based nanogenerators, respectively, which gives a maximum power density of ∼60.75 mW/m2. Here, PDMS-RGO has been introduced on the ZnSnO3 layer to trap the charge on the surface of ZnSnO3 NRs that increases the piezoelectric potential through the surface passivation effect of ZnSnO3 NRs. The cumulative effect of Schottky contact (Cu/CuO), p–n heterojunction (CuO/ZnSnO3), and surface passivation of ZnSnO3 NRs plays a role in enhancing the output performance of the PENG. Thus, these findings show the potential for immense improvement in the field of flexible nanogenerators for mechanical energy harvesting with expressively better piezoelectric performance than those previously reported for powering portable electronic devices.

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