Physics

2D clay minerals have advantages in subnanometer interlayer space, rich surface chemistry, light transparency and low cost for mass production, which enable their applications in mass separation, smart optics, and energy conversion devices. Over the past 30 years, significant progress has been made on scalable fabrication and high-value applications of natural clay minerals-based two-dimensional (2D) materials. Natural clay minerals-based 2D materials have layered structures, high ion conductivity and selectivity, tunable surface charge, remarkable chemical stability, mechanical resilience, low cost and abundance in nature. Here, we provide a comprehensive review of the advances in characterizations, properties and applications of 2D phyllosilicates. First, it summarizes the fundamentals including crystal structure and ion exchange properties of 2D clay minerals. Subsequently, it highlights how advanced characterization techniques and computational methods interconnect the structure and behavior of 2D clay minerals. We then discuss the recently developed fabrication methods of 2D phyllosilicates to make them suitable for the study of intrinsic properties, as well as for scalable devices. Next, it is elaborated on how the intrinsic properties of 2D phyllosilicates such as light transparency, surface chemistry and confined interlayer space influence their applications in ion and molecular separation, energy harvesting, and liquid crystals individually or synergistically, so that the relationship of structure-properties is elucidated. Finally, the next-generation design concepts, including multi-dimensional printing strategy and smart devices, in the fabrication and application fields of 2D clay minerals are proposed.

The growing demands of artificial intelligence and big data require semiconductor technologies that enable high-performance computing with low power consumption. Ferroelectric materials combined with semiconductors are one intriguing alternative for the future needs. For example, thin ferroelectric doped hafnium dioxide, deposited by atomic layer deposition (ALD), is already well integrated and scaled up in current semiconductor device processing. This study investigates ALD growth of HfO2 thin films using CpHf(NMe2)3 and O3 as precursors focusing on interface evolution through low energy ion scattering and x-ray photoelectron spectroscopy (XPS). A flow-type ALD reactor that is in vacuo connected to the surface-sensitive techniques was used allowing for in-depth analysis without air exposure. The study highlights that the full coverage of oxidized TiN substrate is achieved after approximately 30 ALD cycles. The XPS spectra demonstrate interaction between the substrate and the hafnium oxide film suggesting valence and conduction band bending in the films. The findings contribute to the understanding of the deposition, growth, and interface changes for developing thin ferroelectric HfO2.

The large-scale deposition and integration of 2D materials on 200 mm wafers for emerging microelectronic applications are highly challenging. Throughout the processing, significant issues in controlling material growth and patterning must be addressed. Therefore, this study introduces a new approach for bottom-up growth and subsequent patterning of ultrathin 2D WS2 layers on 200 mm wafers. To achieve this, atomic layer deposition (ALD) was used to grow WS2 thin films directly on 200 mm wafers, which were then patterned by photolithography and ion-beam etching. To prevent degradation and delamination of the WS2 layer during patterning, an in situ Al2O3 ALD capping layer is employed. Even after treatment in boiling de-ionized water, which porosifies the Al2O3 as needed for sensing applications, the WS2 and underlying features remain intact. To investigate the effects of patterning and capping processes in detail, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy were used. The detailed analysis shows that the proposed strategies enable patterning of WS2 layers on 200 mm wafers using Al2O3 capping layers. Electrical measurements of the WS2 patterned on interdigitated electrodes show a linear current response and an average resistance of 0.4 ± 0.26 MΩ across the 200 mm wafer. Overall, our findings indicate a promising step toward the scalable integration of WS2 into various micro- and nanosystems, especially sensors, and support future scaling of these processes.

We study the effect of the spatial distribution of active force dipoles on the folding pathways and mechanical stability of rigid-elastic networks using Langevin dynamics simulations. While it has been shown by D. Majumdar, et al. [J. Chem. Phys. 163, 114902 (2025)] that a sharp collapse transition is evident in triangular (elastic) bead-spring networks under the action of contractile (or extensile) force dipoles distributed randomly across the network, here, we show that when the spatial distribution is correlated, e.g., like a patch in the center (``active core'' model) or a bandlike distribution along the periphery (``active periphery'' model), the network undergoes only a partial decrease in size even at large forces, thereby showing an enhanced mechanical stability just from a spatial rearrangement of the active dipoles. Furthermore, an active periphery network exhibits higher mechanical stability initially, for a range of forces, beyond which the active core network becomes more stable. Active fluctuation induced deformation becomes irreversible beyond a threshold force amplitude, which depends on the type of distribution; for a uniform distribution of active dipoles, the irreversibility threshold almost coincides with the critical collapse point, it decreases for the active core network, and is decreased further for the active periphery network. It is demonstrated that irreversibility arises due to plastic deformations, specifically crease formation, which remains irreversible even after the force is turned off or reversed. The folding pathways depend weakly on the temporal stochasticity of the active links, but are highly sensitive to any defects (missing bonds) in the network. Our findings, therefore, suggest active force localization (or delocalization) as a prime method to dynamically alter the mechanical stability and reversibility of the underlying elastic network.

Quantum size effect (QSE) on the electronic structures of nanoscale antiferromagnets with a monolayer (ML) thickness is of fundamental importance in antiferromagnetic (AFM) spintronics. Here, we have carried out systematic studies on the size-dependent unoccupied electronic states of ML Mn nanoislands on Ag(111) by employing scanning tunneling microscopy/spectroscopy (STM/STS) together with density-functional theory (DFT). According to bias-dependent height profiles, a lower apparent height has been found on the larger Mn island within a bias voltage range of $\ifmmode\pm\else\textpm\fi{}1.0\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$, suggesting a smaller Mn--Ag interlayer distance. Additionally, a single broad $\text{d}I\text{/d}U$ peak from small Mn islands gradually evolves into two distinct peaks at approximately $1.3\phantom{\rule{4pt}{0ex}}\text{eV}$ (peak 1) and $1.5\phantom{\rule{4pt}{0ex}}\text{eV}$ (peak 2) as the island size increases. On top of that, peaks 1 and 2 move about $0.37\ifmmode\pm\else\textpm\fi{}0.05\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$ and $0.30\ifmmode\pm\else\textpm\fi{}0.03\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$ toward lower energy positions when the area size of the ML Mn island increases. Given the projected density of states (PDOS) deduced from orbital-dependent electronic band structures of ML Mn/Ag(111), two unoccupied $\mathrm{d}I/\mathrm{d}U$ peaks originate from the contributions of out-of-plane Mn-$3d$ orbitals. Further PDOS comparison analyses reveal that the Mn--Ag interlayer coupling develops a stronger energy shift in unoccupied states than the Mn--Mn atomic bonding, yielding the two-peak feature in $\mathrm{d}I/\mathrm{d}U$ spectra resolved experimentally.

ABSTRACT Electric double‐layer capacitors (EDLCs), which store energy via reversible ion adsorption and desorption at the electrode‐electrolyte interface, hold considerable promise for energy storage under extreme temperature conditions. However, their practical application faces significant limitations associated with temperature‐dependent limitations: at high‐temperature, electrolyte decomposition can reduce Coulombic efficiency or triggers device failure, whereas at low‐temperature, diminished ionic conductivity or electrolyte crystallization leads to performance deterioration or functional breakdown. A comprehensive understanding of these constraints is therefore essential for designing EDLCs capable of operating reliably in extreme environments. This review begins with a systematic overview of the working principles and practical applications of EDLCs, followed by a comparative analysis of various electrolytes, highlighting their respective advantages and shortcomings. Subsequently, we outline specific design principles for both electrolytes and electrodes based on key physicochemical properties and summarize recent advances in high‐temperature, low‐temperature, and wide‐temperature EDLCs. Finally, forward‐looking perspectives and strategic directions are proposed to guide the development of next‐generation EDLCs capable of delivering stable performance under extreme temperatures. This review aims to provide critical insights and rational design guidelines to advance EDLC technology for demanding, extreme‐environment applications.

ABSTRACT Hybrid tin‐lead (Sn–Pb) perovskites, with bandgaps tunable down to 1.25 eV, hold great promise for high‐efficiency photovoltaics. However, their performance is often hampered by the buried interface defects and instability induced by the commonly used hole‐transport layer (HTL), Poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), which suffers from intrinsic hygroscopicity and non‐uniformity. Here, we introduce a multifunctional molecule, (S)‐methyl 2‐amino‐2‐(3‐fluoro‐4‐(trifluoromethyl)phenyl)acetate hydrochloride (MTFP), into PEDOT:PSS to address these issues. MTFP mitigates the hygroscopicity and improves the uniformity of PEDOT:PSS while concurrently modifying the buried interface. It regulates the quinoid structure proportion in PEDOT, optimizes the work function of the HTL, and passivates interfacial defects. These actions collectively enhance charge extraction and promote the crystallization of the overlying perovskite film. Furthermore, the hydrophobic trifluoromethyl group in MTFP significantly boosts the environmental stability of the device. Consequently, the optimized Sn–Pb perovskite solar cells achieve a champion power conversion efficiency of 23.36%, with a high open‐circuit voltage of 0.88 V. This strategy also enables a two‐terminal all‐perovskite tandem solar cell with a remarkable PCE of 28.67%.