An Artificial Neuromorphic Opto‐Gas Synergistic Device Based on a Two‐Dimensional Perovskite Oxide for Acid Rain Warning

ABSTRACT The development of multifunctional artificial synapses capable of integrating molecular sensing and physical stimuli detection remains a challenge due to limited material systems that exhibit both multi‐modal responsiveness and tunable synaptic characteristics. Herein, we report two‐dimensional perovskite oxide La 2 Ti 2 O 7 (LTO) nanosheets that are semiconducting and ion conductive, rendering them sensitive to humidity, NO 2 gas, and light. A two‐terminal device based on the LTO nanosheets exhibited tunable synaptic behaviors and input‐dependent switching between excitatory and inhibitory postsynaptic currents. Importantly, a long‐term inhibitory memory was achieved, resulting from the light‐triggered reaction between environmental H 2 O and NO 2 molecules, which deprived H 2 O from the LTO surface to bring LTO to a high resistance state. As a proof‐of‐concept, our two‐terminal device was employed for evaluation and early warning of potential acid rain scenarios, demonstrating its advantage of reducing system complexity compared to a conventional system that requires multiple sensors and logic processors. Our work provides a new strategy of using multi‐functional sensing materials for artificial synapses in responding to environmental chemical processes.