A Sustainable Organic Memristor with Tunable Switching for Logic Operations and Medical Image Encryption

Organic memristors have emerged as promising candidates for neuromorphic computing and secure information processing. However, challenges remain in developing sustainable active materials, establishing experimentally accessible parameter-performance relationships, and connecting device characteristics to application-oriented circuit functions. Herein, we report a sustainable bio-organic memristor using a zeaxanthin/PVP composite as the functional layer, with Ag and FTO as the top and bottom electrodes. The device exhibits stable bipolar resistive switching, and its memory window can be tuned by the bias range, scan rate, and zeaxanthin concentration. Under ±1.5 V, 1.0 V s^-1, and 10 mg mL^-1, the device shows a stable resistive switching behavior over 100 cycles with a larger HRS/LRS ratio. In addition, the linearized fitting suggests a segmented conduction behavior involving Fowler-Nordheim tunneling, hopping conduction, ohmic transport, Poole-Frenkel emission, and Schottky emission. Based on the experimentally identified switching window and logic threshold, we further construct logic gates, a 2:1 multiplexer, flip-flops, and a 16-bit LFSR-based encryption architecture, and demonstrate XOR-based encryption/decryption of medical CT images at the system level. Therefore, this work provides a sustainable and tunable proof-of-concept platform for linking bio-organic resistive switching materials with logic-oriented secure information processing.