2021/02/18 by Hamid Reza Rasouli, Rasouli, Hamid Reza, Jeongho Kim +13
Earth and Planetary Sciences · Engineering · #Advanced Memory and Neural Computing #Applied Physics (physics.app-ph) #FOS: Physical sciences #Gas Sensing Nanomaterials and Sensors #Geochemistry and Elemental Analysis #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2102.09414
openalex publication_date 2021/02/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Two-dimensional (2D) materials are suitable hosts for the intercalation of extrinsic guest ions such as Li+, Na+ and K+ as the interlayer coupling is weak. This allows ion intercalation engineering of 2D materials, which may be a key to advancing technological applications in energy storage, neuromorphic electronics, and bioelectronics. However, ions that are extrinsic to the host materials possess challenges in fabrication of devices as there are extra steps of ion intercalation. This results in degradation of the long-term stability of the intercalated atomically thin structures. Here, we introduce large-area single-crystal ultra-thin layered MnO2 via chemical vapor deposition, spontaneously intercalated by potassium ions during the synthesis. We studied the ultra-thin 2D K-MnO2 in detail and showed that charge transport in these crystals is dominated by motion of hydrated potassium ions in the interlayer space. Moreover, K-MnO2 crystals exhibit reversible layered-to-spinel phase transition accompanied by an optical contrast change based on the electrical and optical modulation of the potassium and the interlayer water concentration. We used the electric field driven ionic motion in K-MnO2 based devices to demonstrate the memristive properties of two terminal devices. As a possible application we showed that K-MnO2 memristors display synapse-like behavior such as short and long-term potentiation and depression as well as ionic coupling effects.