Transparent, Flexible, Fatigue-Free, Optical-Read, and Nonvolatile Ferroelectric Memories

Perovskite oxide films are widely used in various commercial industries. However, they are usually prepared at high temperature and in oxygen ambience, detrimental to most transparent and flexible substrates and bottom conductive electrodes such as indium tin oxide (ITO). It remains challenging to integrate perovskite oxides into transparent and flexible electronics. Here, the 1.2 wt % Ag-doped ITO (Ag-ITO) grown on a mica substrate is employed as the bottom electrode, which can withstand high temperature and repeated bending, and then we achieve the transparent, flexible, fatigue-free, and optical-read ferroelectric nonvolatile memories based on the mica/Ag-ITO/Bi_3.25La_0.75Ti₃O₁₂/ITO structures. The as-prepared memories show ∼80% transmittance for visible lights and fatigue-free performance after more than 10⁸ writing/erasing cycles. These performances are stable after repeated bending down to 3 mm in a curvature radius. More importantly, the "1/0" state of the memory can be read out by the photovoltaic current rather than destructive polarization switching, an emergent functionality for many applications. This work substantially promotes the applications of perovskite oxide films in transparent and flexible electronics, including wearable devices.