1. Biopolymer-based RRAM
A memory device based on natural organic material is a promising device toward the next generation of nonvolatile nano-electronics. A solution-processed memory device based on chitosan as a natural solid polymer electrolyte can be switched reproducibly between high and low resistance states. In addition, the data retention measurement confirmed the reliability of the chitosan-based nonvolatile memory device. The transparent Ag-embedded chitosan film showed an acceptable and comparable resistive switching behavior on the flexible plastic substrate as well. A cost-effective, environmentally benign memory device using chitosan satisfies the functional requirements of nonvolatile memory operations.
2. Biopolymer-based synapses
The development of electronic devices possessing the functionality of biological synapses is a crucial step toward replicating the capabilities of the human brain. Of the various materials that have been used to realize artificial synapses, renewable natural materials have the advantages of being abundant, inexpensive, biodegradable, and ecologically benign. We report biocompatible artificial synapses based on biopolymers. These artificial synapses can emulate several essential synaptic behaviors including analog memory switching, the short-term plasticity, long-term plasticity, spike-rate-dependent plasticity, and short-term to long-term transition. These results suggest that a biopolymer can be a promising key component for artificial synapses.