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1. Intercalation‐Induced Phase Transitions in Ferroelectric α‐In ₂ Se ₃

   https://doi.org/10.1002/advs.202513712  

   He, Xin; Gong, Zhihao; Wang, Tao; Wang, Baoyu; Liu, Chen; Wang, Ding; Ma, Yinchang; Feng, Pu; Zhang, Chenhui; Hu, Weijin; et al (December 2025, Advanced Science)

   Abstract Specific ions can be intercalated into functional materials using the electrolyte gating technique, which has been widely used to regulate channel conductance in transistors and develop low‐power neuromorphic devices. However, in these devices, fundamental exploration of ion intercalation‐induced structural phase transitions remains largely overlooked and rarely explored. Here, the lithium‐based electrolyte gating technique is used to probe the collective interactions between ions, lattices, and electrons in a van der Waals ferroelectric semiconductor α‐In₂Se₃. Using a polymer electrolyte as the lithium‐ion reservoir and α‐In₂Se₃as the channel material, the intercalated lithium concentration via a gate electric field is modulated. This manipulation drives a phase transition in α‐In₂Se₃from a ferroelectric semiconductor to a dirty metal and finally to a metal, accompanied by a structural transformation. Concurrently, with enhanced intercalation, the ferroelectric hysteresis window progressively narrows and eventually disappears, indicating the evolution from switchable to non‐switchable polarization. This study represents a promising platform for the artificial construction of correlated material systems, enabling a systematic investigation into the interaction of ferroelectricity and electronic conduction using ion intercalation. 

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2. Polymorphism of low dimensional boron nanomaterials driven by electrostatic gating: a computational discovery

   https://doi.org/10.1039/C9NR10774F  

   Jiao, Yalong; Ma, Fengxian; Gu, Jinxing; Chen, Zhongfang; Du, Aijun (May 2020, Nanoscale)

   null (Ed.)

   The successful synthesis of two-dimensional (2D) boron sheets typically relies on the utilization of a silver surface, which acts as a gated substrate compensating for the electron-deficiency of boron. However, how the structures of one-dimensional (1D) boron are affected by the gating effect remains unclear. By means of an unbiased global minimum structure search and density functional theory (DFT) computations, we discovered the coexistence of 2D boron sheets and 1D ribbons triggered by electrostatic gating. Specifically, at a low excess charge density level (<0.1 e per atom), 2D boron sheets dominate the low energy configurations. As the charge density increases (>0.3 e per atom), more 1D boron ribbons emerge, while the number of 2D layers is reduced. Additionally, a number of low-lying 1D boron ribbons were discovered, among which a flat borophene-like ribbon (FBR) was predicted to be stable and possess high mechanical strength. Moreover, the electride Ca 2 N was identified as an ideal substrate for the fabrication of the FBR because of its ability to supply a strong electrostatic field. This work bridges the gap between 2D and 1D boron structures, reveals the polymorphism of 1D boron ribbons under the electrostatic gating effect, and in general provides broad implications for future synthesis and applications of low-dimensional boron materials. 

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3. Is the Chemisorbed CO ₂ in Ionic Liquid Electrolytes Active for Electrochemical Utilization? A Case Study on Carboxylate and Carbamate Speciation

   https://doi.org/10.1149/1945-7111/addf83  

   Coskun, Oguz Kagan; Dongare, Saudagar; Gurkan, Burcu E (June 2025, Journal of The Electrochemical Society)

   This study examines the activity of chemisorbed CO₂species in the microenvironment formed by bifunctional ionic liquids (ILs) in the reactive capture and conversion (RCC) of CO₂to CO on silver. Comparative electroanalytical measurements with imidazolium based ILs were performed to probe the impact of electrostatic interactions, anion and cation basicity, and hydrogen bonding on RCC. Particularly, ILs with 1-ethyl-3-methylimidazolium ([EMIM]⁺) and 1-ethyl-2,3-dimethylimidazolium ([EMMIM]⁺) cations and aprotic heterocyclic anions of 2-cyanopyrrolide ([2-CNpyr]) and 1,2,4-triazolide ([124-Triz]) were examined for RCC. It was found that anion–CO₂carbamate complexes facilitate RCC at significantly lower overpotentials compared to cation–CO₂carboxylate complexes. Additionally, [EMIM]⁺was found to better stabilize anion–CO₂complexes at the interface than [EMMIM]⁺. Furthermore, it was found that 2-CNpyrH that naturally forms during CO₂absorption competes for electrode surface adsorption with the anion–CO₂carbamate complex, thereby reducing the electrochemical activity of the anion–CO₂complex. These results highlight the importance of IL structure in tuning the interfacial interactions and suggest that ILs with anion-dominated CO₂chemisorption enhances CO₂utilization in RCC applications. 

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4. What controls electrostatic vs electrochemical response in electrolyte-gated materials? A perspective on critical materials factors

   https://doi.org/10.1063/5.0087396  

   Leighton, Chris; Birol, Turan; Walter, Jeff (April 2022, APL Materials)

   Electrolyte-gate transistors are a powerful platform for control of material properties, spanning semiconducting behavior, insulator-metal transitions, superconductivity, magnetism, optical properties, etc. When applied to magnetic materials, for example, electrolyte-gate devices are promising for magnetoionics, wherein voltage-driven ionic motion enables low-power control of magnetic order and properties. The mechanisms of electrolyte gating with ionic liquids and gels vary from predominantly electrostatic to entirely electrochemical, however, sometimes even in single material families, for reasons that remain unclear. In this Perspective, we compare literature ionic liquid and ion gel gating data on two rather different material classes—perovskite oxides and pyrite-structure sulfides—seeking to understand which material factors dictate the electrostatic vs electrochemical gate response. From these comparisons, we argue that the ambient-temperature anion vacancy diffusion coefficient ( not the vacancy formation energy) is a critical factor controlling electrostatic vs electrochemical mechanisms in electrolyte gating of these materials. We, in fact, suggest that the diffusivity of lowest-formation-energy defects may often dictate the electrostatic vs electrochemical response in electrolyte-gated inorganic materials, thereby advancing a concrete hypothesis for further exploration in a broader range of materials. 

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5. Electrolyte-gated junctionless III-V Nanowire transistors: a TCAD-based evaluation

   https://doi.org/10.1007/s10825-025-02338-x  

   Islam, Muhammad Shaffatul; Manimaran, Nithil Harris; Abrand, Alireza; Morrell, John Wyatt; Kirmani, Ahmad R; Xu, Ke; Mohseni, Parsian K (August 2025, Journal of Computational Electronics)

   Abstract In this study, we explore the operation and performance of electrolyte-gated junctionless III-V nanowire (NW) transistors featuring compositionally graded In_xGa_1-xAs channels. These devices leverage the electric double-layer (EDL) gating mechanism at the electrolyte/semiconductor interface to achieve ultra-high charge carrier densities, surpassing those possible with conventional oxide dielectrics. Fermi–Dirac statistics are introduced by a numerical method to reproduce associated charge densities of EDL transistors. A 1 nm interfacial HfO₂layer is introduced to capture the electrostatics of the EDL, prevent charge transfer between the electrolyte and the semiconductor, and mimic the Stern layer. Device simulations are conducted to optimize the heterostructured NW composition and doping profile, followed by benchmarking against traditional HfO₂-gated structures. The EDL-gated device achieves anI_ON/I_OFFratio of 10⁶, with a subthreshold slope of 60 mV/dec and a threshold voltage of 0.31 V at a low drain voltage of 0.3 V, indicating a two-order magnitude improvement over conventional junctionless oxide-gated NW transistors. Computational methodologies include finite element modeling in COMSOL to extract voltage-dependent ion densities and subsequent device simulations using Silvaco's Atlas software. The results indicate that the optimized EDL-gated device exhibits superior electrostatic integrity and performance metrics compared to conventional gating methods. The findings underscore the potential of EDL gating in III-V NW configurations for advanced electronic applications, demonstrating significant improvements in switching characteristics and power efficiency. Further optimization and exploration of bias-dependent ionic concentrations and configurable device geometries highlight the robustness and scalability of this approach for next-generation low-power electronics. 

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