Guo Rui, You Lu, Lin Weinan, Abdelsamie Amr, Shu Xinyu, Zhou Guowei, Chen Shaohai, Liu Liang, Yan Xiaobing, Wang Junling, Chen Jingsheng
Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore.
College of Electron and Information Engineering, Hebei University, Baoding, 071002, China.
Nat Commun. 2020 May 22;11(1):2571. doi: 10.1038/s41467-020-16465-5.
Flexoelectricity induced by the strain gradient is attracting much attention due to its potential applications in electronic devices. Here, by combining a tunable flexoelectric effect and the ferroelectric photovoltaic effect, we demonstrate the continuous tunability of photoconductance in BiFeO films. The BiFeO film epitaxially grown on SrTiO is transferred to a flexible substrate by dissolving a sacrificing layer. The tunable flexoelectricity is achieved by bending the flexible substrate which induces a nonuniform lattice distortion in BiFeO and thus influences the inversion asymmetry of the film. Multilevel conductance is thus realized through the coupling between flexoelectric and ferroelectric photovoltaic effect in freestanding BiFeO. The strain gradient induced multilevel photoconductance shows very good reproducibility by bending the flexible BiFeO device. This control strategy offers an alternative degree of freedom to tailor the physical properties of flexible devices and thus provides a compelling toolbox for flexible materials in a wide range of applications.
由应变梯度引起的挠曲电效应因其在电子器件中的潜在应用而备受关注。在此，通过结合可调谐挠曲电效应和铁电光伏效应，我们展示了BiFeO薄膜中光电导的连续可调性。在SrTiO上外延生长的BiFeO薄膜通过溶解牺牲层转移到柔性衬底上。通过弯曲柔性衬底实现可调谐挠曲电效应，这会在BiFeO中引起不均匀的晶格畸变，从而影响薄膜的反转不对称性。因此，通过独立的BiFeO中挠曲电效应与铁电光伏效应之间的耦合实现了多级电导。通过弯曲柔性BiFeO器件，应变梯度诱导的多级光电导显示出非常好的可重复性。这种控制策略为调整柔性器件的物理性质提供了另一种自由度，从而为广泛应用中的柔性材料提供了一个引人注目的工具箱。
