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Rational manipulation and assembly of discrete colloidal particles into architected superstructures have enabled several applications in materials science and nanotechnology. Optical manipulation techniques, typically operated in fluid media, facilitate the precise arrangement of colloidal particles into superstructures by using focused laser beams. However, as the optical energy is turned off, the inherent Brownian motion of the particles in fluid media impedes the retention and reconfiguration of such superstructures. Overcoming this fundamental limitation, we present on-demand, three-dimensional (3D) optical manipulation of colloidal particles in a phase-change solid medium made of surfactant bilayers. Unlike liquid crystal media, the lack of fluid flow within the bilayer media enables the assembly and retention of colloids for diverse spatial configurations. By utilizing the optically controlled temperature-dependent interactions between the particles and their surrounding media, we experimentally exhibit the holonomic microscale control of diverse particles for repeatable, reconfigurable, and controlled colloidal arrangements in 3D. Finally, we demonstrate tunable light-matter interactions between the particles and 2D materials by successfully manipulating and retaining these particles at fixed distances from the 2D material layers. Our experimental results demonstrate that the particles can be retained for over 120 days without any change in their relative positions or degradation in the bilayers. With the capability of arranging particles in 3D configurations with long-term stability, our platform pushes the frontiers of optical manipulation for distinct applications such as metamaterial fabrication, information storage, and security.

2D carbon allotropes with moderated electronic bandgaps are highly desirable for next‐generation carbon‐based nanoelectronics beyond graphene. Herein, the structural and electronic properties of bilayer α‐graphyne have been systematically investigated by using first‐principles calculations. Consequently, in addition to typical van der Waals (vdW) stacks of single‐layer α‐graphyne, new 2D carbon allotropes with purely sp2 or sp3 hybridizations can be achieved, arising from the absence of intralayer acetylene linkages during structural relaxation. Compared to the Dirac semimetallic behavior of monolayer α‐graphyne, the electronic structure of vdW bilayer α‐graphyne can be further modulated by stacking patterns, yet retains metallic characteristics. In contrast, intrinsic semiconducting characteristics can be observed in the proposed new 2D carbon allotropes with tunable bandgaps dependent on the in‐plane biaxial strain. Correspondingly, a pristine 2D carbon sheet with only sp2 hybridization exhibits a promising direct bandgap of 1.062 eV, while the sp3‐hybridized carbon network possesses an indirect bandgap of 1.708 eV, which can be further converted to the direct type under small compressive strains, implying great potential in future carbon‐based nanoelectronic applications beyond graphene. Also, this work provides a new approach for developing novel carbon allotropes via the vertical stacking of graphyne with acetylenic linkages. [ABSTRACT FROM AUTHOR]

Mesoscopic simulations are performed to study the absorption of eriodictyol and favipiravir for a charged protein inserted in a lipid bilayer. The dissipative particle dynamics (DPD) force field parameters of both compounds are obtained to approximate the experimental solubility in water. The lipid bilayer has 6 hydrocarbon tail beads and a head group. Electrostatic interactions are treated by Ewald sums with charge distributions to avoid the formation of ion pairs. The helical structure of the protein is maintained by using a harmonic potential on the dihedral angles of the backbone beads. The potential is successfully applied to an α-helix 1L4X and lysozime proteins. The calculated radius of gyration of lysozime is around 1.6 nm compared to ∼1.5 nm reported by Vaiwala et al. [Soft Matter, 17 (42), 9772–9785 (2021). doi:10.1039/D1SM01194D] who used a slightly different approach to maintain the helical structure. A charged lysozyme-type protein is used as a model within the lipid bilayer and it is in contact with water on both sides of the bilayer. The active ingredients without protein are found at the interface of the lipid bilayer but their concentration decreases when the protein is included because some of them diffuse to the interior of the protein. [ABSTRACT FROM AUTHOR]

Plasmonic applications have traditionally relied on noble metals such as gold (Au) and silver (Ag) for their excellent plasmonic performance in the visible and near-infrared spectrum. However, these metals are costly, scarce, and have limitations such as low stability (Ag) and interband transition losses, which restrict their spectral range. To address these issues, alternative plasmonic materials have been explored. One such material is aluminum (Al), which is inexpensive, abundant, and exhibits remarkable plasmonic properties in the UV region as well as wide tunability. Al is also compatible with complementary metal–oxide semiconductor (CMOS) fabrication processes and is very stable due to its ultrathin native oxide layer. Alloying different metals can combine their advantageous properties, resulting in enhanced tunable optical characteristics. This study investigates the LSPR properties of AgAl alloy nanoparticles grown after the annealing of precursor AgAl bilayer films. Interestingly, LSPRs were also observed in some cases for the as-deposited bilayers. The experimental results were complemented with simulations conducted via the rigorous coupled-wave analysis (RCWA) method. The investigated materials could be potentially useful for applications in energy harvesting or color printing. [ABSTRACT FROM AUTHOR]

An investigation on a single mode optical fiber sensor-based surface plasmon resonance was carried out in this work. A titanium dioxide (TiO2) coated gold Nano-column (Au) are deposited on the proposed sensor and theoretically analyzed using COMSOL Muliphysics software 5.3. Presence of TiO2 over the Au Nano-column can improve the sensitivity of the sensor and tune the resonance peak of transmission spectrum from visible region to near-infrared region. The size effect of TiO2 nanoparticles on the sensor performance is studied. The optimum parameters of such as Au size and separation width between the Au Nano-column have been selected to enhance the performance of the sensor. In comparison, the sensor with TiO2 over Au Nano-column is significantly improve the sensitivity and develop the sensor performance. The greater sensitivity of 5243.76 nm/RIU (refractive index unit) is obtained of sensor with TiO2 over Au Nano-column when the external refractive index of analyte is varying from 1.33 to 1.39, while sensitivity of the sensor coated with Au Nano-column is obtained to be 4643.17 nm/RIU for the same analyte range. Above results can be used to predict the best parameters values of the sensor that corresponding to the greatest sensitivities of detection and finally opening new study in the field of gas sensors. [ABSTRACT FROM AUTHOR]

Interest in fullerene-based polymer structures has renewed due to the development of synthesis technologies using thin C60 polymers. Fullerene networks are good semiconductors. In this paper, heterostructure complexes composed of C60 polymer networks on atomically thin dielectric substrates are modeled. Small tensile and compressive deformations make it possible to ensure appropriate placement of monolayer boron nitride with fullerene networks. The choice of a piezoelectric boron nitride substrate was dictated by interest in their applicability in mechanoelectric, photoelectronic, and electro-optical devices with the ability to control their properties. The results we obtained show that C60 polymer/h-BN heterostructures are stable compounds. The van der Waals interaction that arises between them affects their electronic and optical properties. [ABSTRACT FROM AUTHOR]

The article presents the results of a systematic study of the crystalline structure, microstructure, and hysteresis properties of (Cr80Mn20)/Fe bilayers, deposited on buffer coatings of various metals (Cr, Fe, W, Ta). It has been established that depending on the composition of the buffer coating and the thickness of the Cr–Mn layer, the latter develops body-centered cubic structure with either the (110) or (200) texture, or none. It is shown that the Cr–Mn layer is a source of increased coercivity in the adjacent Fe layer and when is in a certain structural state and has a relatively large thickness (100 nm) induces exchange bias in the Fe layer. The regularities obtained are interpreted in terms of the antiferromagnetic ordering of Cr–Mn and its relatively weak magnetic anisotropy. [ABSTRACT FROM AUTHOR]

Forming heterostructures of 2D metals and semiconductors using chemical vapor deposition (CVD) has significant potential to effectively reduce contact resistance in electronic devices. However, semiconducting transition metal dichalcogenide (TMD) layers in metal–semiconductor heterostructures are currently restricted to monolayers despite the superior mobility and density of states in bilayer TMDs. Herein, NbSe2/bilayer Nb‐doped WSe2 metal/semiconductor heterostructure from exfoliated WSe2 flakes are synthesized first. The exfoliated WSe2 bulk crystals on an Nb‐coated substrate are heated to 950 °C under a flow of selenium vapor, and then the NbSe2/bilayer Nb‐doped WSe2 heterostructures are formed. Statistics on the number of Nb‐doped WSe2 layers grown on a 1 cm × 1 cm CVD substrate shows that 65% of the Nb‐doped WSe2 layers are grown as bilayers. X‐ray photoelectron spectroscopy, optical microscopy, and transmission electron microscopy clearly clarify the number of Nb‐doped WSe2 layers and heterostructure of NbSe2/bilayer Nb‐doped WSe2. Electrical measurements using Cr contacts show that bilayer Nb‐doped WSe2 displays 7‐ and 10‐times higher mobility and on/off ratio than monolayer Nb‐doped WSe2. The mobility and on/off ratio are further doubled in NbSe2/bilayer Nb‐doped WSe2 contact compared to Cr/bilayer Nb‐doped WSe2 contact, attributed to a clean interface in vertical stack heterostructure, enhancing electrical performance. [ABSTRACT FROM AUTHOR]

The synthesis of graphene oxide-zinc oxide, graphene oxide- silver, graphene oxide thin layers, and graphene oxide-zinc/graphene oxide-silver bilayer was done using a method called spray pyrolysis. Characterization of the synthesized layers was done by X ray diffraction, transmission electron microscope, atomic force microscope, photo-luminescence, FTIR and BET analyses. Based on the TEM images, the given nano-composites are formed and GO can be a suitable platform for the growth of silver and ZnO nano-particles and prevents their accumulation. According to the AFM images, GO-ZnO/GO-Ag sample has the lowest roughness. PL spectrum showed a broad emission peak for GO-Ag layer at a wavelength of approximately 550 nm, which is consistent with the reported band gap of 3.6eV. From BET results, the surface area was obtained 4 m²g-1 and 14 m²g-1, for GO and GO-Ag samples respectively which were greater than the similar work. The pore diameter of GO-ZnO sample was obtained equal to 16.5 nm, indicating the superiority of the meso-holes in GO-ZnO sample. Also, the surface area of GO-ZnO/GO-Ag bilayer was around 3.6 times larger than the surface area of ZnO. The contact angles of droplet with the surface in GO, GO-Ag, GO-ZnO, GO-ZnO/GO-Ag samples are 55.02, 60.24, 31.28, 56.35, respectively. [ABSTRACT FROM AUTHOR]

Abstract Two twisted bismuth bilayers, TBB, each with 120 atoms, are studied using their electron density of states and their vibrational density of states using first‐principles calculations. Metallic character at the Fermi level is found for the non‐rotated sample as well as for each sample rotated 0.5°, 1.0°, 1.5°, 2.0°, 2.5°, 3.0°, 4.0°, 5.0°, 6.0°, 7.0°, 8.0°, and 10° with respect to each other. Assuming that the superconductivity is BCS‐type and the invariance of the Cooper pairing potential, a maximum superconducting temperature TC ≈1.8 K is predicted for a magic angle of 0.5° between the two bilayers, increasing the superconducting transition temperature from the experimentally measured value of 0.53 mK for the Wyckoff structure of crystalline bismuth.

To facilitate the integration of a fragrance encapsulation system into different products to achieve effective releases, a dual-responsive release system with pH and thermal trigger control is designed in this work. A series of ZIF-8 (M) and bilayer ZIF-8-on-ZIF-8 (MM) materials are synthesized by a solvent method at room temperature. The fragrance is encapsulated into the ZIFs by dynamic adsorption or in situ encapsulation combined dynamic adsorption. The fragrance loading contributed by dynamic adsorption was as high as 80%. The fragrance loaded in the double-layer MM host was almost twice that of the monolayer host M due to the stronger electrostatic interaction between MM and vanillin. In the pH and thermal trigger response release experiments, the second MOF layer in the MM host, as a controlled entity, greatly improved the load and kinetic equilibrium time of vanillin, and realized the controlled release of guest molecules. The developed dual-responsive release system in this work exhibits great potential in daily chemical products. [ABSTRACT FROM AUTHOR]

Response of lipid bilayers to external mechanical stimuli is an active area of research with implications for fundamental and synthetic cell biology. Developing novel tools for systematically imposing mechanical strains and non-invasively mapping out interfacial (membrane) stress distributions on lipid bilayers can accelerate research in this field. We report a miniature platform to manipulate model cell membranes in the form of droplet interface bilayers (DIBs), and non-invasively measure spatio-temporally resolved interfacial stresses using two photon fluorescence lifetime imaging of an interfacially active molecular flipper (Flipper-TR). We established the effectiveness of the developed framework by investigating interfacial stresses accompanying three key processes associated with DIBs: thin film drainage between lipid monolayer coated droplets, bilayer formation, and bilayer separation. The measurements revealed fundamental aspects of DIBs including the existence of a radially decaying interfacial stress distribution post bilayer formation, and the simultaneous build up and decay of stress respectively at the bilayer corner and center during bilayer separation. Finally, utilizing interfacial rheology measurements and MD simulations, we also reveal that the tested molecular flipper is sensitive to membrane fluidity that changes with interfacial stress - expanding the scientific understanding of how molecular flippers sense stress. [ABSTRACT FROM AUTHOR]

Advances in soft robotics strongly rely on the development and manufacturing of new responsive soft materials. In particular, light‐based 3D printing techniques, and especially, digital light processing (DLP), offer a versatile platform for the fast manufacturing of complex 3D/4D structures with a high spatial resolution. In this work, DLP all‐printed bilayered structures exhibiting reversible and multi‐responsive behavior are presented for the first time. For this purpose, liquid crystal elastomers (LCEs) are used as active layers and combined with a printable non‐responsive elastomer acting as a passive layer. Furthermore, selective light response is incorporated by embedding various organic dyes absorbing light at different regimes in the active layers. An in‐depth characterization of the single materials and printed bilayers demonstrates a reversible and selective response. Last, the versatility of the approach is shown by DLP printing a bilayered complex 3D structure consisting of four different materials (a passive and three different LCE active materials), which exhibit different actuation patterns when irradiated with different wavelengths of light. [ABSTRACT FROM AUTHOR]

The antiparallel current‐induced spin polarization (CISP) in an inversion‐symmetric double‐quantum‐well structure with the antiparallel Rashba effective magnetic field is calculated by solving the Boltzmann equation which is derived for the distribution operator in layer‐pseudospin space in the relaxation‐time approximation. The antiparallel CISP in an analytical form, obtained for constant momentum relaxation time in the limit of large Fermi energy, exhibits factor‐two increase with increasing the interlayer‐tunneling strength. This increase originates from the correction (to the semiclassical CISP) created by the subband mixing due to the momentum dependence of the Rashba effective magnetic field. The present interlayer‐coupling dependence of the antiparallel CISP is successfully explained as the layer‐pseudospin Hanle effect in which the spin in the original Hanle effect is replaced by the layer pseudospin. The present finding suggests that the correction by band mixing can be significant in the transport properties of various systems with the momentum‐dependent effective magnetic field. [ABSTRACT FROM AUTHOR]

Plasmonic applications have traditionally relied on noble metals such as gold (Au) and silver (Ag) for their excellent plasmonic performance in the visible and near-infrared spectrum. However, these metals are costly, scarce, and have limitations such as low stability (Ag) and interband transition losses, which restrict their spectral range. To address these issues, alternative plasmonic materials have been explored. One such material is aluminum (Al), which is inexpensive, abundant, and exhibits remarkable plasmonic properties in the UV region as well as wide tunability. Al is also compatible with complementary metal–oxide semiconductor (CMOS) fabrication processes and is very stable due to its ultrathin native oxide layer. Alloying different metals can combine their advantageous properties, resulting in enhanced tunable optical characteristics. This study investigates the LSPR properties of AgAl alloy nanoparticles grown after the annealing of precursor AgAl bilayer films. Interestingly, LSPRs were also observed in some cases for the as-deposited bilayers. The experimental results were complemented with simulations conducted via the rigorous coupled-wave analysis (RCWA) method. The investigated materials could be potentially useful for applications in energy harvesting or color printing.

The present study investigates the influence of layer thickness and stacking engineering on the electronic, structural, and optical properties of monolayer PtS2 using the density functional theory calculations. The monolayer PtS2 (m‐PtS2) is found to possess an indirect bandgap, 1.73 eV, which reduces to 0.67 eV for bilayer PtS2 (b‐PtS2). Impact of stacking engineering on the electronic and optical properties is explored through six different stacking patterns and the AA1 configuration is found to be most stable displaying the highest reflectance and refractive index values. Moreover, this PtS2 bilayer structure demonstrates promising light absorption capability over a wide range (2–12 eV) with the position of absorption edge showing a redshift as the layers number increases. These computed electronic and optical properties of monolayer PtS2 validate it as a prospective material for future optoelectronic devices. [ABSTRACT FROM AUTHOR]

A polymer component in immiscible polymer blends results in phase separation, leading to polymer morphologies that vary from isolated spherical particles to a continuous matrix phase depending on the polymer weight ratio. This work demonstrates that a polymer component with a low weight fraction can form a continuous matrix phase, rather than isolated spherical particles, which is unprecedented. Bar‐coating a solution of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) blended with a high fraction of polydimethylsiloxane (PDMS) and a surfactant results in a continuous PEDOT:PSS matrix distributed with spherical PDMS islands. The PEDOT:PSS and PDMS in the coated layer phase separate, forming a bilayer structure owing to its different affinities to the poly(ethylene terephthalate) (PET) substrate. When cured at 100 °C, water and other volatiles in the PEDOT:PSS phase in the bottom layer evaporate, generating spaces that are subsequently filled with PDMS from the phase‐separated top layer. The continuous PEDOT:PSS matrix ensures excellent conductivity (66.17 Ω·sq−1), while the PDMS islands provide high stretchability. The electrical conductivity of the new electrodes varies negligibly when stretched at 50% strain and is even maintained up to 150% strain. The electrodes exhibit high transparency (≈90% at 550 nm) and electromechanical stability over 1000 cycles of 30% stretch/release tests. [ABSTRACT FROM AUTHOR]

Two–dimensional (2D) 4H‐polytype tin disulfide (SnS2) flakes are synthesized using the chemical vapor transport technique. The weak Van der Waals force between the 2D SnS2 layers offers an easy exfoliation of flakes down to a bilayer of thickness ≈2.02 (±0.1) nm using a mechanical exfoliation technique. The optical and field effect transistor (FET) characteristics of the exfoliated 2D 4H‐SnS2 layers are studied. The exfoliated layers are used to fabricate the ≈13‐layered SnS2 FET. The 4H‐SnS2 exhibits a high on/off ratio of ≈106 and mobility ≈1–4 cm2 V−1 s−1. The low mobility of the 4H‐SnS2 FET devices shows an insulating state concordant with the 2D Motts variable range hopping mechanism at varying temperatures. Moreover, it is found that the optical bandgap of the 2D SnS2 single‐crystal layers is largely widened for the bilayers and tri‐layers. The optical bandgap energies vary in the range of 2.56–1.99 eV. The significant alteration in bandgap energies of ≈0.57 eV offers downscaling of the 2D nanoscale semiconducting devices. Such layer‐sensitive changes in optical transmittance, absorbance, and bandgap energies are reflected in Commission Internationale de L'Eclairage (CIE) chromaticity, showing the distinct color of transmittance through various 2D 4H‐SnS2 layers. [ABSTRACT FROM AUTHOR]

Cellular membranes are complex systems that consist of hundreds of different lipid species. Their investigation often relies on simple bilayer models including few synthetic lipid species. Glycerophospholipids (GPLs) extracted from cells are a valuable resource to produce advanced models of biological membranes. Here, we present the optimisation of a method previously reported by our team for the extraction and purification of various GPL mixtures from Pichia pastoris. The implementation of an additional purification step by High Performance Liquid Chromatography-Evaporative Light Scattering Detector (HPLC-ELSD) enabled for a better separation of the GPL mixtures from the neutral lipid fraction that includes sterols, and also allowed for the GPLs to be purified according to their different polar headgroups. Pure GPL mixtures at significantly high yields were produced through this approach. For this study, we utilised phoshatidylcholine (PC), phosphatidylserine (PS) and phosphatidylglycerol (PG) mixtures. These exhibit a single composition of the polar head, i.e. , PC, PS or PG, but contain several molecular species consisting of acyl chains of varying length and unsaturation, which were determined by Gas Chromatography (GC). The lipid mixtures were produced both in their hydrogenous (H) and deuterated (D) versions and were used to form lipid bilayers both on solid substrates and as vesicles in solution. The supported lipid bilayers were characterised by quartz crystal microbalance with dissipation monitoring (QCM-D) and neutron reflectometry (NR), whereas the vesicles by small angle X-ray (SAXS) and neutron scattering (SANS). Our results show that despite differences in the acyl chain composition, the hydrogenous and deuterated extracts produced bilayers with very comparable structures, which makes them valuable to design experiments involving selective deuteration with techniques such as NMR, neutron scattering or infrared spectroscopy. [ABSTRACT FROM AUTHOR]

The bilayer’s formations of amphiphilic molecules or polyions of different ionogenity comprise the basic building units of most organic biological and non-biological systems. A theory has evolved to explain their behaviour during the creation of those organized structures, such as anisotropic liquid crystal (LC) in lyotropic (especially hydrotropic) systems and polyelectrolyte multilayer (PEM) assemblies. Particular attention has been paid to the temperature and the important role of water in the formation and behaviour of the bilayers. A novel insight into the formation of hydrotropic liquid LC systems and their thermotropic behaviour is presented. In this context, the systems PEM assemblies are also discussed. Essentially, a structuralised form of water fills out continuous and discontinuous, i.e., confined, nano-spaces among hydrophilic interfaces of bilayers, controlling their supramolecular structure through a system of attractive and repulsive hydration forces. The character of those sophisticated bonding hydration systems is predestined by the composition and type of these hydrophilic interface groups. The miscellaneous complexity of the bilayer’s aqueous systems suggests the need to study these examples in greater detail. Therefore, the bilayer’s processes connected with disruption as far as destruction of bilayers are mentioned, i.e., the processes with the highest potential to combat bacteria, fungi, and viruses, such as in a situation where a person exhales a breath of micro-droplets containing virus nanoparticles (e.g., the COVID-19 virus).

The exchange of ions across interfaces is key to the field of iontronics, where the properties of the device can be altered by the local ion concentration. This study investigates a complex oxide system where structural and electronic phase transitions can be driven by changes in the concentration of oxygen ions. In situ coherent X‐ray studies are conducted on epitaxial bilayers of insulating SrCoO2.5 and metallic SrCoO3 − δ. The diffusion of oxygen ions across the bilayer is studied with X‐ray photon correlation spectroscopy to capture the dynamical behavior of the interface in reducing and oxidizing environments. The behavior is strongly asymmetric, with much slower dynamics appearing in reducing versus oxidizing environments. According to the correlation functions determined from different points in reciprocal space, this study finds that the dynamics near the center of the SrCoO2.5 crystal are generally similar to those near the heterointerfaces. The results suggest that the interface is stable and reversible, making SrCoOx a model system for the study of iontronic behavior. [ABSTRACT FROM AUTHOR]

This paper presents the basic tools used to describe the global symmetry of so‐called bilayer structures obtained when two differently oriented crystalline monoatomic layers of the same structure are superimposed and displaced with respect to each other. The 2D nature of the layers leads to the use of complex numbers that allows for simple explicit analytical expressions of the symmetry properties involved in standard bicrystallography [Gratias & Portier (1982). J. Phys. Colloq.43, C6‐15–C6‐24; Pond & Vlachavas (1983). Proc. R. Soc. Lond. Ser. A, 386, 95–143]. The focus here is on the twist rotations such that the superimposition of the two layers generates a coincidence lattice. The set of such coincidence rotations plotted as a function of the lengths of their coincidence lattice unit‐cell nodes exhibits remarkable arithmetic properties. The second part of the paper is devoted to determination of the space groups of the bilayers as a function of the rigid‐body translation associated with the coincidence rotation. These general results are exemplified with a detailed study of graphene bilayers, showing that the possible symmetries of graphene bilayers with a coincidence lattice, whatever the rotation and the rigid‐body translation, are distributed in only six distinct types of space groups. The appendix discusses some generalized cases of heterophase bilayers with coincidence lattices due to specific lattice constant ratios, and mechanical deformation by elongation and shear of a layer on top of an undeformed one. [ABSTRACT FROM AUTHOR]

Electrochromism, a well‐defined phenomenon of bias‐induced reversible color switching, has led to real applications in several smart devices including smart windows and self‐powered batteries and solar panels. For these applications, the electrochromic (EC) materials need to be integrated as solid‐state devices. Deciphering ways to recreate a conventional device requires understanding of basic structure and its working. A thorough discussion is provided here regarding various materials that can act as chromophores when treated with some electric bias in addition to a few parameters that dictatehow fairly the device performs. The next important aspect is the device design, the skeleton of which usually includes conducting substrates, EC active materials, and an electrolyte. Step‐by‐step, various available device paradigms are discussed starting from a single EC electrode then joining a blank substrate to fabricate a monolayer electrochromic device (ECD) moving onto bi‐layer ECDs, and finally, all‐in‐one EC gel, which is devoid of any proper layered pattern. A thorough discussion regarding various application‐oriented structural modifications is provided. Challenges and the areas that need to be addressed in immediate future are discussed. [ABSTRACT FROM AUTHOR]

In this work, the effect of orbital hybridizations at the interface on the exchange bias in SmFeO3/NiFe (3 nm) and SmFeO3/CoFeB (3 nm) bilayers prepared by pulsed laser deposition (PLD) combined with magnetron-sputtering technique on SrTiO3 (100) substrates was investigated. X-ray photoelectron spectroscopy (XPS) was employed to obtain the valence states of related elements in each layer and interface of the bilayer. With the purpose of studying the electronic structure of bilayers, especially the orbital hybridizations at the interface of bilayers, X-ray absorption spectroscopy (XAS) was also accomplished. Remarkably, the hybridizations of Co 3d - O 2p and Ni 3d - O 2p are confirmed in the SFO/CoFeB and SFO/NiFe bilayers, respectively. Meantime, it is observed that the bilayers exhibit different exchange bias effect (EB) from magnetization investigations, which are probably resulted from Co/Ni ions in oxidized states and the higher strength of hybridization of Ni 3d - O 2p than that of Co 3d - O 2p. [ABSTRACT FROM AUTHOR]

Abstract The exchange of ions across interfaces is key to the field of iontronics, where the properties of the device can be altered by the local ion concentration. This study investigates a complex oxide system where structural and electronic phase transitions can be driven by changes in the concentration of oxygen ions. In situ coherent X‐ray studies are conducted on epitaxial bilayers of insulating SrCoO2.5 and metallic SrCoO3 − δ. The diffusion of oxygen ions across the bilayer is studied with X‐ray photon correlation spectroscopy to capture the dynamical behavior of the interface in reducing and oxidizing environments. The behavior is strongly asymmetric, with much slower dynamics appearing in reducing versus oxidizing environments. According to the correlation functions determined from different points in reciprocal space, this study finds that the dynamics near the center of the SrCoO2.5 crystal are generally similar to those near the heterointerfaces. The results suggest that the interface is stable and reversible, making SrCoOx a model system for the study of iontronic behavior.

The interfacial defects or imperfections in the multilayer perovskite solar cells (PSCs) are detrimental for efficient and stable devices. To produce highly efficient and stable PSCs, a bilayer between the interfaces of electron‐transport material/perovskite and perovskite/hole‐transport material can be useful for suppressing recombinations at these interfaces. To passivate the interfacial defects at the perovskite/SnO2 and perovskite/Spiro‐OMeTAD for three absorber materials (CsPbI3, FAPbI3, and Cs0.05(FA0.83MA0.17)0.95Pb(I0.83Br0.17)3), a thin layer of WO3 and poly‐bathocuproine interfacial layer is explored using solar cell capacitance simulation in 1D. The optimized device photovoltaic performances significantly improve using bilayers. The power conversion efficiency for the FAPbI3‐based PSCs in bilayer configuration is more than 12% as compared to pristine, whereas open‐circuit voltage is improved by over 13%. The enhancement in device performance is attributed to the reduction of interfacial defects at both the electron transport layer/perovskite and perovskite/hole transport layer interfaces. The proposed interface modification strategy provides a novel approach for fabricating efficient perovskite devices. [ABSTRACT FROM AUTHOR]

The phase composition of periodic Mo/Si multilayers with different thicknesses of silicon and molybdenum layers, and bilayer films with the combination of Mo–on–Si and Si–on–Mo with varying thicknesses of the upper layers (Mo or Si) were investigated. X-ray diffraction and high-resolution transmission electron microscopy were used for the investigation of phases and microstructure of periodic multilayer. Core-levels and valence-bands X-ray photoelectron spectroscopy was performed for the study of electronic structure and phase composition of surface and interfaces in bilayer films. Although the intermetallic silicide phases (Mo5Si3, Mo3Si and MoSi2) in multilayer and bilayer systems evolved similar, differences were observed in specific phases compared to bilayer systems in the Mo–on–Si and Si–on–Mo sequences. The amorphous silicon layer in periodic multilayers was highly disordered as compared to the amorphous layer of silicon in bilayer films. This was originated to formation of specific silicide phases in the periodic multilayers and bilayers systems. [ABSTRACT FROM AUTHOR]

Response to external stimuli plays a significant role in the environmental adaptation of living matters and intelligent devices. Most stimulus–response systems in nature can respond to appropriate stimuli, and inhibit the response under excessive stimuli, such as excessive heat or water, which can be called overload protection. However, even though various responsive materials have been developed for different stimuli, most of them are not protective against the overload stimuli. In this work, a bilayer actuator based on semicrystalline polyurethane is designed, which can respond differently to proper stimuli and excessive stimuli, i.e., water. This actuator can bend gradually under the proper stimulation of water, but will straighten and even bend reversely with excessive stimulation. The mechanism behind the reversible and adjustable actuator with overload protection is investigated both experimentally and theoretically, and the competition between dynamic factors and thermodynamic stability in the swelling process is considered the main cause. [ABSTRACT FROM AUTHOR]

Efficient replacement of materials based on critical elements such as cobalt is one of the greatest challenges facing the field of solid oxide cells. New generation materials, free of cobalt show potential to replace conventional materials. However, these materials are characterised by poor ability to block chromium diffusion. This article described the study of CuMn 1.7 Fe 0.3 O 4 (CMFO) spinel combined with single metal oxide (Y 2 O 3 or Gd 2 O 3) thin films as protective coatings for steel interconnects. CMFO was examined using XRD and TPR. Coated steel samples were oxidised in an air atmosphere at 700 °C for 4000 h. The coatings and oxide scale microstructures and cross-sections were examined by CRI, XRD, and SEM-EDX. The electrical properties of the steel-coating system were evaluated using Area Specific Resistance measurements. Based on the results obtained, it can be concluded that the use of thin layers of rare earth oxides allowed for better blocking of chromium diffusion. [Display omitted] [ABSTRACT FROM AUTHOR]

Electron and lattice heat transport have been investigated in bilayer thin films of gold and CoSb _3 after photo-excitation of the nanometric top gold layer through picosecond x-ray scattering in a pump-probe setup. The kinetics of heat transfer are detected by thermal lattice expansion and compared to simulations based on the two-temperature model of coupling of electron and phonon degrees of freedom. The unexpected observation of a larger portion of the deposited heat being detected in the underlying CoSb _3 layer before the topmost gold layer is heated supports the picture of transport of the photo-excited electrons from gold to the underlying layer to be converted into lattice heat. The change of partition of heat between the gold and CoSb _3 layer with laser fluence and wavelength (either exciting intraband transitions or additionally interband transitions) is rooted in the amplitude of electron temperature. Higher electron temperatures result in a longer equilibration time with the lattice and thus a larger proportion of ballistic electron transport across the interface.

In this study, CrN/ZrN multilayer nanostructured coatings with different bilayers (10, 20, and 30) were created by the cathodic arc evaporation. The electrochemical behavior of samples was evaluated by polarization and impedance spectroscopy tests in the Ringer medium and the pin on disk test was used to investigate the tribological behavior of the samples. The results of measurements showed that the electrochemical and tribological behavior of the coatings depends on the number of bilayers and by rising the number of bilayers, the coating shows higher corrosion resistance and better tribological performance. Field emission scanning electron microscopy (FE-SEM) images of the specimens after exposure to the corrosion medium showed that the number of surface cavities were formed by the coating that had the highest number of bilayers comparing with other coatings were quite fewer in number and smaller in diameter. The results of the pin on disk test showed that by increasing the number of bilayers from 10 to 30, the coefficient of friction and wear rate decreased and the 30L coating ‌showed better wear resistance.

The bilayer's formations of amphiphilic molecules or polyions of different ionogenity comprise the basic building units of most organic biological and non-biological systems. A theory has evolved to explain their behaviour during the creation of those organized structures, such as anisotropic liquid crystal (LC) in lyotropic (especially hydrotropic) systems and polyelectrolyte multilayer (PEM) assemblies. Particular attention has been paid to the temperature and the important role of water in the formation and behaviour of the bilayers. A novel insight into the formation of hydrotropic liquid LC systems and their thermotropic behaviour is presented. In this context, the systems PEM assemblies are also discussed. Essentially, a structuralised form of water fills out continuous and discontinuous, i.e., confined, nano-spaces among hydrophilic interfaces of bilayers, controlling their supramolecular structure through a system of attractive and repulsive hydration forces. The character of those sophisticated bonding hydration systems is predestined by the composition and type of these hydrophilic interface groups. The miscellaneous complexity of the bilayer's aqueous systems suggests the need to study these examples in greater detail. Therefore, the bilayer's processes connected with disruption as far as destruction of bilayers are mentioned, i.e., the processes with the highest potential to combat bacteria, fungi, and viruses, such as in a situation where a person exhales a breath of micro-droplets containing virus nanoparticles (e.g., the COVID-19 virus). [ABSTRACT FROM AUTHOR]

Herein, solution‐processed indium gallium zinc oxide (IGZO) thin‐film transistors (TFTs) with a bilayer structure are investigated by embedding an ultrathin layer of indium zinc oxide (IZO) between the gate dielectric and IGZO film. The optimized IGZO/IZO bilayer TFTs exhibit a high field‐effect mobility (μFE) of 8.3 cm2 V−1 s−1, and the bias‐stress stability of the bilayer TFTs is greatly improved compared with that of the single‐layer IGZO devices. In addition, temperature‐dependent mobility and VT are investigated to reveal the trap distribution in the bilayer IGZO/IZO and single‐layer IGZO TFTs. Moreover, low‐voltage bilayer TFTs with a high mobility of 10.4 cm2 V−1 s−1 are demonstrated. [ABSTRACT FROM AUTHOR]

[Display omitted] Membranes based on cyclodextrin complexes can be used as functional nanocarrier envelopers by chemical modifications of the cyclodextrin hydroxyl groups or by encapsulating different ligands in their cavities. Molecular dynamics simulations of monolayers and bilayers based on supramolecular complexes consisting of two α or β-cyclodextrin and one sodium dodecylsulfate or dodecane at 283 K and at 298 K were performed. It is shown that the structure and main interactions stabilizing the membranes, as well as their permeability to water and ions can be tuned by changing the cyclodextrin, the ligand, the number of layers or/and the temperature. These results provide new evidences about both their dynamic nature and the interactions responsible for the stabilization of the membranes and will facilitate the design of new functional capsides and applications based on cyclodextrin complexes. [ABSTRACT FROM AUTHOR]

Using a multiscale analysis, we derive a sharp interface limit for the dynamics of bilayer structures of the functionalized Cahn–Hilliard equation with a cutoff diffusion mobility M(u) that is degenerate for u ≤ 0 and a continuously differentiable double-well potential W(u). We show that the bilayer interface does not move in the t = O(1) time scale. The interface motion occurs in the t = O(ε−1 ) time scale and is determined by porous medium diffusion processes in both phases with no jumps on the interface. In the longer O(ε−2 ) time scale, the interface motion is a complex combination of porous medium diffusion processes in both phases and the property of mass conservation. [ABSTRACT FROM AUTHOR]

Molecular doping is an effective means to tune the optoelectronic properties of organic semiconductors. Despite its versatility, its application in bulk heterojunction (BHJ) organic solar cells (OSCs) is still limited, especially blend‐cast doping. Difficulties in desolving molecular dopants in weakly polar solvents have led to the formation of undesired structures, with relatively high concentrations of dopants affecting the bicontinuous BHJ morphology. Bilayer OSCs are stacked structures with sequential deposition of donor and acceptor films, which make important contributions to the fine tuning of morphology and balanced charge transport. The sequential deposition of thin films in bilayer devices organically facilitates the sequential doping of pure donor polymers by dopants. The sequential doping of the dopant at the interface between the donor and the acceptor can efficiently improve the carrier mobility and the charge transfer between the donor and the acceptor without damaging the quality of the film, thus improving the device performance efficiently. With three different dopants F4TCNQ, F6TCNNQ, and BCF, sequential interfacial doping in bilayer devices is found to be a versatile and effective method to improve device performance. Making this simple doping strategy promising for high‐performance bilayer OSCs, it is evaluated as a promising alternative to BHJ OSCs. [ABSTRACT FROM AUTHOR]

The combination of comprehensive surface passivation and effective interface carriers transfer plays a critical role in high‐performance perovskite solar cells. A 2D structure is an important approach for surface passivation of perovskite film, however, its large band gap could compromise carrier transfer. Herein, we synthesize a new molecule 2‐thiopheneethylamine thiocyanate (TEASCN) for the construction of bilayer quasi‐2D structure precisely on a tin‐lead mixed perovskite surface. This bilayer structure can passivate the perovskite surface and ensure effective carriers transfer simultaneously. As a result, the open‐circuit voltage (Voc) of the device is increased without sacrificing short‐circuit current density (Jsc), giving rise to a high certified efficiency from a credible third‐party certification of narrow band gap perovskite solar cells. Furthermore, theoretical simulation indicates that the inclusion of TEASCN makes the bilayer structure thermodynamically more stable, which provides a strategy to tailor the number of layers of quasi‐2D perovskite structures. [ABSTRACT FROM AUTHOR]

As reported herein, a bilayer coating approach using poly(vinyl alcohol) (PVOH) and zein is employed to enhance the water vapor and oxygen barrier properties of paper materials. The coating was applied onto three different types of paper substrates to study the general applicability of this approach. The bilayer‐coated paper samples exhibited a reduction of up to 65% in their water vapor transmission rate in comparison to the corresponding uncoated paper substrates at 23°C and 50% relative humidity. In addition, the bilayer‐coated paper samples showed at least a 40‐fold decrease in oxygen transmission rate from that of the uncoated paper samples. In addition, the coated paper showed excellent thermal stability and mechanical properties. Scanning electron microscopy confirmed that the obtained coated paper has a smooth texture without pores. Pulp was recovered from the coated paper by washing with water/ethanol. Thus, this work provides a unique coated paper with excellent barrier properties and therefore has the potential for real‐world application as an alternative to single‐use plastics. [ABSTRACT FROM AUTHOR]

The native environment for a membrane protein is a phospholipid bilayer. Because the protein is immobilized on NMR timescales by the interactions within a bilayer membrane, solid-state NMR methods are essential to obtain high-resolution spectra. Approaches have been developed for both unoriented and oriented samples, however, they all rest on the foundation of the most fundamental aspects of solid-state NMR, and the chemical shift and homo- and hetero-nuclear dipole-dipole interactions. Solid-state NMR has advanced sufficiently to enable the structures of membrane proteins to be determined under near-native conditions in phospholipid bilayers.

The bandgap is one of the most fundamental properties of condensed matter. However, an accurate calculation of its value, which could potentially allow experimentalists to identify materials suitable for device applications, is very computationally expensive. Here, active machine learning algorithms are used to leverage a limited number of accurate density functional theory calculations to robustly predict the bandgap of a very large number of novel 2D heterostructures. Using this approach, a database of ≈2.2 million bandgap values for various novel 2D van der Waals heterostructures is produced.

The fine structure of the exciton spectrum, containing optically allowed (bright) and forbidden (dark) exciton states, determines the radiation efficiency in nanostructures. Time‐resolved microphotoluminescence in MoS2 monolayers (MLs) and bilayers (BLs), both unstrained and compressively strained, in a wide temperature range (10–300 K), is studied to distinguish between exciton states optically allowed and forbidden, both in spin and in momentum, as well as to estimate their characteristic decay times and contributions to the total radiation intensity. The decay times are found to either increase or decrease with increasing temperature, indicating the lowest bright or lowest dark state, respectively. The results unambiguously show that, in an unstrained ML, the spin‐allowed state is the lowest for a series of A excitons (1.9 eV), with the dark state being <2 meV higher, and that the splitting energy can increase several times at compression. In contrast, in the indirect exciton series in BLs (1.5 eV), the spin‐forbidden state is the lowest, being about 3 meV below the bright one. The strong effect of strain on the exciton spectrum can explain the large scatter among the published data and must be taken into account to realize the desired optical properties of 2D MoS2. [ABSTRACT FROM AUTHOR]

The fine structure of the exciton spectrum, containing optically allowed (bright) and forbidden (dark) exciton states, determines the radiation efficiency in nanostructures. Time‐resolved microphotoluminescence in MoS2 monolayers (MLs) and bilayers (BLs), both unstrained and compressively strained, in a wide temperature range (10–300 K), is studied to distinguish between exciton states optically allowed and forbidden, both in spin and in momentum, as well as to estimate their characteristic decay times and contributions to the total radiation intensity. The decay times are found to either increase or decrease with increasing temperature, indicating the lowest bright or lowest dark state, respectively. The results unambiguously show that, in an unstrained ML, the spin‐allowed state is the lowest for a series of A excitons (1.9 eV), with the dark state being <2 meV higher, and that the splitting energy can increase several times at compression. In contrast, in the indirect exciton series in BLs (1.5 eV), the spin‐forbidden state is the lowest, being about 3 meV below the bright one. The strong effect of strain on the exciton spectrum can explain the large scatter among the published data and must be taken into account to realize the desired optical properties of 2D MoS2. [ABSTRACT FROM AUTHOR]

Within the Green's function formalism, the magnetization induced by the inverse proximity effect in bilayers containing a superconductor and a strongly spin-polarized ferromagnetic metal is studied. The Usadel equations written for the dirty superconductor model are solved with boundary conditions suitable for strongly spin-polarized ferromagnetic materials. The cases of near-critical temperatures and a weak proximity effect are considered. The dependences of the induced magnetization on the superconductor thickness, temperature, transparency of the superconductor–ferromagnet interface, and the spin mixing angle are studied. It is shown that the stronger the proximity effect, the weaker the inverse proximity effect. [ABSTRACT FROM AUTHOR]

Synthesis of compositionally graded versions of PbZr(1-x)Ti(x)O3 thin films results in unprecedented strains (as large as ≈4.5 × 10(5) m(-1)) and correspondingly unexpected crystal structures, ferroelectric domain structures, and properties. This includes the observation of built-in electric fields in films as large as 200 kV/cm. Compositional and strain gradients could represent a new direction of strain-control of materials.

We consider a bulk system of ferroelectric bilayer with an antiferroelectric interface coupling between two similar materials which have second-order phase transitions. Landau theory and Landau–Khalatnikov equation are used to study the dynamic switching phenomenon of this ferroelectric bilayers under a step electric field. A bilinear coupling that achieved a symmetry condition is taken into account in the Landau free-energy expression. We found that switching time is decreased for the system of weak antiferroelectric interface coupling, as well as for the system when the thickness ratio between the two layers is large. It is shown here by dynamic switching that the polarization reversal occurs in one step in the contrary to the static dielectric hysteresis loop. Negative and positive peaks of switching current is discussed. [ABSTRACT FROM AUTHOR]

Changes in the cholesterol (Chol) content of biological membranes are known to alter the physicochemical properties of the lipid lamella and consequently the function of membrane-associated enzymes. To characterize these changes, we used steady-state and time resolved fluorescence spectroscopy and two photon-excitation microscopy techniques. The membrane systems were chosen according to the techniques that were used: large unilamellar vesicles (LUVs) for cuvette and giant unilamellar vesicles (GUVs) for microscopy measurements; they were prepared from dipalmitoyl phosphatidylcholine (DPPC) and dioctadecyl phosphatidylcholine (DOPC) in mixtures that are well known to form lipid domains. Two fluorescent probes, which insert into different regions of the bilayer, were selected: 1,6-diphenyl-1,3,5-hexatriene (DPH) was located at the deep hydrophobic core of the acyl chain regions and 2-dimethylamino-6-lauroylnaphthalene (Laurdan) at the hydrophilic-hydrophobic membrane interface. Our spectroscopy results show that (i) the changes induced by cholesterol in the deep hydrophobic phospholipid acyl chain domain are different from the ones observed in the superficial region of the hydrophilic-hydrophobic interface, and these changes depend on the state of the lamella and (ii) the incorporation of cholesterol into the lamella induces an increase in the orientation dynamics in the deep region of the phospholipid acyl chains with a corresponding decrease in the orientation at the region close to the polar lipid headgroups. The microscopy data from DOPC/DPPC/Chol GUVs using Laurdan generalized polarization (Laurdan GP) suggest that a high cholesterol content in the bilayer weakens the stability of the water hydrogen bond network and hence the stability of the liquid-ordered phase (Lo).

The effect of a middle-layer of thickness t1 with intermediate Young's modulus and yield strength in between a hard coating of thickness t2 and a softer spherical substrate of radius R on the yield inception of a coated system is investigated. Finite element method is used to model bilayer-coated spheres flattened by a rigid flat. It is found that the addition of the middle-layer can enhance or reduce the resistance to yield inception depending on its dimensionless thickness t1/t and t/R where t is the total thickness of the two coating layers. Some practical results are presented, to enable optimum selection of bilayer coated system and prevention of undesired weakening effect.