Photoelectric memristor with reconfigurable photoconductivity for neuromorphic computing

Real-time switching between positive and negative photoconductivity is becoming increasingly important in the development of optoelectronic technology. In this work, we demonstrate a solution-processed Ruddlesden-Popper phase Ba₂TiO₄-based memristor. Through the synergistic effect of optical pulse and external electric field, it realizes the switching between positive photoconductivity and negative photoconductivity. The device achieved typical synaptic behaviors such as excitatory/inhibitory postsynaptic currents, paired-pulse facilitation, and long-term plasticity. It also simulates the advanced behaviors of human learning and memory. The excellent performance of the device is mainly attributed to the vacancy trapping carriers in Ba₂TiO₄. After the photogenerated carriers are captured by the vacancy defects, a built-in electric field will be formed. By combining the synergistic effects of light-induced internal electric fields and external electric fields, positive and negative photoconductive characteristics can be switched. This has enabled image recognition, motion detection, and reconfigurable logic operations. This research is of great significance to realize the integration of sensing, storage, and computing.