In Situ Quantification of Strain‐Induced Piezoelectric Potential of Dynamically Bending ZnO Microwires

Abstract

The piezoelectric properties of semiconductor micro/nanowires (M/NWs) are crucial for optimizing semiconductors’ electronic structure and carrier dynamics. However, the dynamic characterization of the piezoelectric properties of M/NWs remains challenging. Here, a Kelvin probe force microscopy technique based on a dual‐probe atomic force microscope is developed to achieve in situ piezoelectric potential measurements of dynamic bending MWs. This technique can not only characterize the surface potential on different crystal faces of ZnO MWs in a natural state through controllable axial rotation, but also investigate the piezoelectric potential of the dynamically bending flake‐like ZnO MW at different points and under different strain loads. The results show that the surface potentials of different faces/positions of the ZnO MWs are varied significantly, and determine that the quasi‐static conditions piezo‐strain factor of the flake‐like ZnO MW is 0.28 V/%, while the factor was 0.14 V/% under low‐frequency (⩽5 Hz) sinusoidal strain loading. This work provides a significant methodology to further study piezoelectric materials, and it aims to facilitate their applications in piezoelectric devices and systems.

Tumor microenvironment-responsive self-assembly of barium titanate nanoparticles with enhanced piezoelectric catalysis capabilities for efficient tumor therapy

“…The periodic mechanical stress of ultrasound will cause the deformation of the piezoelectric material and generate polarization inside the crystal, thereby effectively inducing the separation of electrons and holes at the interface and finally catalyzing the generation of ROS [ [23] , [24] , [25] , [26] ]. To date, a series of piezoelectric materials such as zinc oxide (ZnO) [ 27 , 28 ], boron nitride (BN) [ 29 , 30 ], and barium titanate (BTO) [ 31 , 32 ] have realized the application in biomedicine; among them, BTO NPs have become widely used sonosensitizers in SDT due to their good biocompatibility, low cytotoxicity, and strong piezoelectricity [ [33] , [34] , [35] , [36] ]. However, SDT strategies based on BTO NPs still face difficulties in the selectivity of delivery and precision of treatment.…”