摘要
By engineering strain gradients in dielectrics,the flexoelectric effect can be created,which yields interesting physical properties via electromechanical coupling.Here,we report flexoelectric-induced photovoltaic effects in centrosymmetric LaFeO_(3) thin-film heterostructures grown on flexible mica sub-strates,in which partial relaxation of lattice-mismatch strain against LaAlO_(3) stretching layers results in giant strain gradients and pronounced electrical polarizations.The flexoelectric polarization modulates band alignment and leads to significant photovoltaic effects with a short-circuit current density of~0.4 mA/cm^(2) and an open circuit voltage of~-0.45 V in Pt/LaFeO_(3)/LaNiO_(3) devices.In addition,by con-cavely/convexly bending the mica substrate,mechanical strain gradients give rise to bi-directionally tunable photocurrents,in which continuously change of short-circuit current density with a magni-tude of~100% and good reproducibility in repetitive bending operations are observed in the Pt/LaFeO_(3)/LaNiO_(3) devices.The present work demonstrates an approach to design self-powered photoelectric de-vices with an electromechanical degree of freedom based on the flexoelectric effect in flexible thin-film heterostructures.
基金
This work was jointly sponsored by Natural Science Foundation of China(51872148)
Natural Science Foundation of Shandong Province(ZR2020JQ03)
D.W.acknowledges financial support from Natural Science Foundation of China(51725203 and U1932115)
Z.W.acknowledges financial support from the Taishan Scholar Program of Shandong Province(tsqn201812045)
the Youth Innovation Team Project of Shandong Provincial Education Department(2019KJJ012).
