An Artificial Flexible Visual Memory System Based on an UV‐Motivated Memristor

For the mimicry of human visual memory, a prominent challenge is how to detect and store the image information by electronic devices, which demands a multifunctional integration to sense light like eyes and to memorize image information like the brain by transforming optical signals to electrical signals that can be recognized by electronic devices. Although current image sensors can perceive simple images in real time, the image information fades away when the external image stimuli are removed. The deficiency between the state‐of‐the‐art image sensors and visual memory system inspires the logical integration of image sensors and memory devices to realize the sensing and memory process toward light information for the bionic design of human visual memory. Hence, a facile architecture is designed to construct artificial flexible visual memory system by employing an UV‐motivated memristor. The visual memory arrays can realize the detection and memory process of UV light distribution with a patterned image for a long‐term retention and the stored image information can be reset by a negative voltage sweep and reprogrammed to the same or an other image distribution, which proves the effective reusability. These results provide new opportunities for the mimicry of human visual memory and enable the flexible visual memory device to be applied in future wearable electronics, electronic eyes, multifunctional robotics, and auxiliary equipment for visual handicapped.     

Epitaxial Lift‐Off of Centimeter‐Scaled Spinel Ferrite Oxide Thin Films for Flexible Electronics

Mechanical flexibility of electronic devices has attracted much attention from research due to the great demand in practical applications and rich commercial value. Integration of functional oxide materials in flexible polymer materials has proven an effective way to achieve flexibility of functional electronic devices. However, the chemical and mechanical incompatibilities at the interfaces of dissimilar materials make it still a big challenge to synthesize high‐quality single‐crystalline oxide thin film directly on flexible polymer substrates. This study reports an improved method that is employed to successfully transfer a centimeter‐scaled single‐crystalline LiFe₅O₈ thin film on polyimide substrate. Structural characterizations show that the transferred films have essentially no difference in comparison with the as‐grown films with respect to the microstructure. In particular, the transferred LiFe₅O₈ films exhibit excellent magnetic properties under various mechanical bending statuses and show excellent fatigue properties during the bending cycle tests. These results demonstrate that the improved transfer method provides an effective way to compose single‐crystalline functional oxide thin films onto flexible substrates for applications in flexible and wearable electronics.