IJSNM副主编 | 厦门大学侯旭教授团队：仿生纳流离子学，荣获2024年度IUPAC化学领域十大新兴技术

Electric-double-layer-gated 2D transistors for bioinspired sensors and neuromorphic devices

ABSTRACT

Electric double layer (EDL) gating is a technique in which ions in an electrolyte modulate the charge transport in an electronic material through electrical field effects. A sub-nanogap capacitor is induced at the interface of electrolyte/semiconductor under the external electrical field and the capacitor has an ultrahigh capacitance density (~µF cm−2). Recently, EDL gating technique, as an interfacial gating, is widely used in two-dimensional (2D) crystals for various sophisticated materials characterization and device applications. This review introduces the EDL-gated transistors based on 2D materials and their applications in the field of bioinspired optoelectronic detection, sensing, logic circuits, and neuromorphic computation.

Lin, X., Li, Y., Lei, Y., & Sun, Q. (2024). Electric-double-layer-gated 2D transistors for bioinspired sensors and neuromorphic devices. International Journal of Smart and Nano Materials, 15(1), 238–259. https://doi.org/10.1080/19475411.2024.2306837

Current progress in glass-based nanochannels

ABSTRACT

Glass-based nanochannels have become powerful tools for chemical and biological sensing due to their advantages of easy preparation, flexible modification, and high sensitivity. Lately, research on ion transport behaviors in glass-based nanochannels and their applications in nanofluidic iontronics has gradually become a focus, including various ion transport behaviors such as resistive-pulse, ion rectification, ionic current memory, etc. In this review, we summarize the progress of manufacturing methods for glass-based nanochannels and discuss several typical ion transport behaviors of glass-based nanochannels, as well as the main application scenarios of glass-based nanochannels in terms of biosensing, detection, and neuromorphic functions. The enormous assistance of artificial intelligence in the standardized manufacturing process of glass-based nanochannels was anticipated, and the potential development of glass-based nanochannels in achieving neuromorphic functions was expected.

Ling, Y., Yang, X., Zhou, L., Lei, Z., Hou, Y., & Hou, X. (2024). Current progress in glass-based nanochannels. International Journal of Smart and Nano Materials, 15(1), 222–237. https://doi.org/10.1080/19475411.2024.2305544

Bioinspired ionic control for energy and information flow

ABSTRACT

The control of ion transport by responding to stimulus is a necessary condition for the existence of life. Bioinspired iontronics could enable anomalous ion dynamics in the nanoconfined spaces, creating many efficient energy systems and neuromorphic in-sensor computing networks. Unlike traditional electronics based on von Neumann computing architecture, the Boolean logic computing based on the iontronics could avoid complex wiring with higher energy efficiency and programmable neuromorphic logic. Here, a systematic summary on the state of art in bioinspired iontronics is presented and the stimulus from chemical potentials, electric fields, light, heat, piezo and magnetic fields on ion dynamics are reviewed. Challenges and perspectives are also addressed in the aspects of iontronic integrated systems. It is believed that comprehensive investigations in bioinspired ionic control will accelerate the development on more efficient energy and information flow for the futuristic human-machine interface.

Peng, P., Qian, H., Liu, J., Wang, Z., & Wei, D. (2024). Bioinspired ionic control for energy and information flow. International Journal of Smart and Nano Materials, 15(1), 198–221. https://doi.org/10.1080/19475411.2024.2305393

Confined gas transport in low-dimensional materials

ABSTRACT

Gas transport under confinement exhibits a plethora of physical and chemical phenomena that differ from those observed in bulk media, owing to the deviations of continuum description at the molecular level. In biological systems, gas channels play indispensable roles in various physiological functions by regulating gas transport across cell membranes. Therefore, investigating gas transport under such confinement is crucial for comprehending cellular physiological activities. Moreover, leveraging these underlying mechanisms can enable the construction of bioinspired artificial nanofluidic devices with tailored gas transport properties akin to those found in biological channels. This review provides a comprehensive summary of confined gas transport mechanisms, focusing on the unique effects arising from nanoconfinement. Additionally, we categorize nanoconfinement spaces based on dimensionality to elucidate their control over gas transport behavior. Finally, we highlight the potential of bioinspired smart gas membranes that mimic precise modulation of transportation observed in organisms. To conclude, we present a concise outlook on the challenges and opportunities in this rapidly expanding field.

Duan, H., Zhuang, Z., Yang, J., Zhang, S., & Wang, L. (2024). Confined gas transport in low-dimensional materials. International Journal of Smart and Nano Materials, 15(1), 127–164. https://doi.org/10.1080/19475411.2023.2300348

Selective and asymmetric ion transport in covalent organic framework-based two-dimensional nanofluidic devices

ABSTRACT

Two-dimensional (2D) covalent organic framework (COF) membranes featuring well-aligned and programmable vertical nanochannels have emerged as a promising candidate for advanced nanofluidic devices and showcased vast potential in the fields of smart-gating, ion-separation, and energy-harvesting. However, the transverse interlayer nanochannels with a height of sub-nanometer-scale in 2D-COF membranes have scarcely been studied in comparison. Here, we report the ion transport characteristics in 2D interlayer nanochannels of protonated COF membranes. The distinct surface-charge-governed ionic conductance in domination of electrolyte concentration below 10−3 M as well as the exceptional anion/cation (Cl−/K+) selectivity is revealed due to the pronounced charge and nano-confinement effects. Additionally, evident ion current rectification is witnessed when incorporating asymmetric geometry into the system, which is attributed to the dynamic process of ion enrichment and dissipation within the protonated nanochannels. This work offers immense prospects for 2D-COF membranes in the fields of biomimetic nanofluidic devices and cutting-edge electronic devices.

Huang, L. Q., Chen, S., Mo, R. J., Li, Z. Q., & Xia, X. H. (2023). Selective and asymmetric ion transport in covalent organic framework-based two-dimensional nanofluidic devices. International Journal of Smart and Nano Materials, 15(1), 186–197. https://doi.org/10.1080/19475411.2023.2288954

ABSTRACT

Reliable and controllable switches are crucial in nanofluidics and iontronics. Ion channels found in nature serve as a rich source of inspiration due to their intricate mechanisms modulated by stimuli like pressure, temperature, chemical species, and voltage. The artificial replication of the properties of these channels is challenging due to their complex chemistry, limited stability range, and intricate moving parts, allosterically modulated. Nonetheless, we can harness some of the gating mechanisms of ion channels for nanofluidic and iontronic purposes. This theoretical and computational study explores the use of electrowetting in simple hydrophobic nanopores to control their conductance using an external applied voltage. We employ restrained molecular dynamics to calculate the free energy required for wetting a model nanopore under different voltages. Utilizing a simple theory, we generate free energy profiles across a wide voltage range. We also computed transition rates between conductive and non-conductive states, showing their voltage dependence and how this behavior can impair memory to the system, resembling the memristor behavior voltage-gated channels in the brain. The proposed framework provides a promising avenue for designing and controlling hydrophobic nanopores via electrowetting, enabling potential applications in neuromorphic iontronics.

Paulo, G., Gubbiotti, A., Di Muccio, G., & Giacomello, A. (2024). Voltage controlled iontronic switches: a computational method to predict electrowetting in hydrophobically gated nanopores. International Journal of Smart and Nano Materials, 15(1), 165–185. https://doi.org/10.1080/19475411.2023.2300332

ABSTRACT

Rare-earth elements (REEs) are critical to modern industry but difficult to separate due to their subtle and monotonic changes in physicochemical properties. MoS2-based two-dimensional (2D) materials offer novel opportunities for enhancing REE separation, exhibiting a distinct volcano-shaped transport performance distribution that peaks at Sm3+. However, the specific contributions of thermodynamic and kinetic factors to ion transport within 2D confinement remain unclear. In this study, we conducted a series of non-equilibrium all-atom molecular dynamics (MD) simulations to explore the effects of interlayer spacing and external pressure on the transport of lanthanide ions in Å-scale acetate functionalized 2D MoS2 (MoS2-COOH) channels. We examined ion entry and permeation rates, water flux, dehydration, and binding modes. The simulation results reveal that the transport trends of lanthanide ions are jointly driven by the dehydration degree and the relative-binding strengths of ions to water and to the acetate within the 2D channels. Notably, the dehydration pattern of lanthanide ions during permeation is closely linked to kinetic factors. Overall, this study provides a detailed atomistic understanding of the mechanisms underlying lanthanide ion transport under confinement. These findings point to the significant potential for tuning confinement and chemical functionalization within Å-scale channels for more efficient REE separation.

Xiong, Q., Liu, C., & Schatz, G. C. (2024). Effects of interlayer spacing and applied pressure on the lanthanide transport in MoS2-based two-dimensional channels. International Journal of Smart and Nano Materials, 15(3), 579–592. https://doi.org/10.1080/19475411.2024.2387926