Flexoelectric effect describes the electromechanical coupling between the strain gradient and its internal polarization in all dielectrics. Despite this universality, the resulting flexoelectric field remains small at the macroscopic level. However, in nanosystems, the size-dependent effect of flexoelectricity becomes increasingly significant, leading to a notable flexoelectric field that can strongly influence the material’s physical properties. This review aims to explore the flexoelectric effect specifically at the nanoscale. We achieve this by examining strain gradients generated through two distinct methods: internal inhomogeneous strain and external stimulation. In addition, advanced synthesis techniques are utilized to enhance the properties and functionalities associated with flexoelectricity. Furthermore, we delve into other coupled phenomena observed in thin films, including the coupling and utilization of flexomagnetic and flexophotovoltaic effects. This review presents the latest advancements in these areas and highlights their role in driving further breakthroughs in the field of flexoelectricity.

挠曲电效应是一种应变梯度与电极化(正挠曲电效应)或电场强度梯度与应变(逆挠曲电效应)之间的力电耦合效应。与压电效应不同，挠曲电效应不受材料对称性、Curie温度所限制，且随着材料尺寸减小而不断增强，因而具有广阔的研究与应用前景。本文主要总结了挠曲电效应的发展历史、挠曲电系数测量、挠曲电效应增强机制以及当前研究进展，重点介绍了挠曲电效应在传感器、致动器、机械存储器、挠曲电压电复合材料、俘能器以及新型电子器件等领域应用的最新研究进展，最后对挠曲电效应的发展前景进行了展望。

文章基于挠曲电和应变梯度效应的共同影响, 建立了静拉伸下一维压电半导体力电耦合计算模型, 数值分析了挠曲电和应变梯度效应对位移、电势、电位移、载流子分布等物理场的影响。结果表明: 两种效应对机械位移场没有影响, 但对各电相关物理场的分布影响显著; 挠曲电效应对压电结构本身的压电性能有抑制作用, 而应变梯度效应却增强了其压电特性。本研究为压电类微纳结构的机电特性分析提供了理论指导。

介绍了一种用布拉格光纤光栅制作啁啾光纤光栅的方法。采用氢氟酸腐蚀布拉格光纤光栅,使光栅的横截面沿光栅轴向逐渐变小,然后对光栅施加1.50N的拉力,在光栅轴向建立应变梯度,制作出长15mm、峰值反射率达92%、反射半高宽为5nm的啁啾光纤光栅。