The autonomous and real-time ion monitoring in wearables demands sustainable materials capable of self-powered and ion sensing (especially Na and K). The alteration of such ions causes severe health issues such as neurological dysfunction, cardiac arrhythmias, or metabolic disorders. Here, we introduce 2D biotite as a natural multifunctional material that unifies ion sensing and energy harvesting in a single material platform. The surface charges and high surface-to-volume ratio of 2D biotite make it highly sensitive and selective to electrolytes ions. The 2D biotite-based flexible TENG generated output voltages ranging from +/- 10.4 to +/- 24.3 V over a frequency range of 1-10 Hz and 1-6 V human-motion harvesting, confirming wearable self-powered capability. Density functional theory and non-equilibrium Green's function simulations validated the performance hierarchy based on adsorption energetics and charge transfer. The current-voltage curves demonstrate that simulation results reproduce the same trend observed experimentally. The sequence follows NaOH/biotite > KOH/biotite > NaCl/biotite > KCl/biotite > CaCl2/biotite > pure biotite, as seen in the experimental data as well. The work positions natural 2D biotite as a scalable, tunable, and eco-benign platform for next-generation self-powered smart wearable systems with multiple applications ranging from medical diagnostics to ion sensing and efficient energy generators.

Abstract We report a facile strategy to exfoliate and disperse transition metal dichalcogenides (WS2, MoS2, VS2) and MXene (Ti3C2Tx) directly within liquid crystals (LCs), yielding stable multifunctional nanocomposites. The multifunctional composite films exhibited unique properties, highlighted by the nanomaterial-mediated cholesteric-to-isotropic transition in the LC/Ti3C2Tx composite films at lower applied fields than the LC film alone. In addition, we demonstrated the preparation of free-standing LC/Ti3C2Tx composite films having both distinct LC and nanomaterial optical characteristics. Our solvent-free approach also enabled alignment-layer-free blade coating of birefringent composite films without postsynthesis processing. Significant polarization-dependent absorption was observed for LC/MoS2 films due to the anisotropy of the composite. The facile film processing and composite film properties are appealing for the fabrication of next-generation optoelectronics.

Understanding the relationship between molecular structure and anisotropic photothermal behavior is essential for developing light-responsive materials with directionally controllable behavior. In this study, we report the design of a thiazole-functionalized azobenzene mesogen, PB-ABT, which exhibits efficient photothermal conversion under 405 nm light. The introduction of an electron-rich thiazole moiety induces intramolecular charge transfer (ICT), enhancing π-π stacking and facilitating non-radiative decay pathways essential for thermal energy generation. Comparative studies with a symmetric reference compound (PB-Azo) reveal that PB-ABT exhibits stronger intermolecular interaction, more stable self-assembly, and significantly improved anisotropic photothermal behavior. The identification of a clear correlation between molecular arrangement and directional photothermal dissipation provides answers to the long-standing limitations of isotropic behavior and the unclear mechanisms in organic photothermal systems. These anisotropic photothermal properties originate from two key factors: anisotropic surface morphology and direction-dependent non-radiative dissipation occurring along π-π stacking pathways, demonstrating a direct link between molecular arrangement and macroscopic heat generation. This work provides a molecular-level strategy for constructing 405 nm-responsive organic materials with both optical and thermal anisotropy, offering new insight into the design of aligned photothermal systems for advanced encryptable applications.

We demonstrate shear-printed layered photonic films with vivid structural coloration from bio-derived cellulose nanocrystals and highly aligned Ti3C2Tx MXene nanoflakes. These ultrathin films (700-1500 nm) show high light transmittance above 40% in the visible range. In reflectance mode, however, the films appear vividly colored and iridescent due to the multiple distinct photonic bandgaps in the visible and near-infrared ranges, which are rarely observed in CNC composites. The structural coloration is controlled by the stacking of MXene nanoscale-thin layers separated by the thicker cellulose nanocrystals matrix, as confirmed by photonic simulations. The unique combination of distinctly different optical appearances in transmittance and reflectance modes occurs in films printed with just a few layers. This is because of the molecularly smooth interfaces and the high refractive contrast between bio-based and inorganic phases, which result in a concurrence of constructive and destructive interference. These lamellar biophotonic films open the possibilities for advanced radiative cooling, camouflaging, multifunctional capacitors, and optical filtration applications, while the cellulose nanocrystals matrix strengthens their flexibility, robustness, and facilitates sustainability.

This article provides a brief overview of the research on localized optical states called Tamm plasmons (TPs) and their potential applications, which have been extensively studied in recent decades. These states arise under the influence of incident light at the interface between a metal film and a medium with the properties of a Bragg mirror, or between two media with the properties of a Bragg mirror. The localization of the states in the interfacial region is a consequence of the negative dielectric constant of the metal and the presence of a photonic band gap of the Bragg reflector. Optically, TPs appear as resonant reflection dips or peaks in the transmission and absorption spectra in the region corresponding to the photonic band gap. The relative simplicity of creating a Tamm structure and the significant sensitivity of TPs to its parameters make them attractive for applications. The formation of broadband and tunable TP modes in hybrid structures containing, in particular, rugate filters and porous distributed Bragg reflectors are considered. Considerable attention is paid to TP designs that include liquid crystals, which allow for the remote tuning of the TP spectrum without the mechanical restructuring of the system. The application of TPs in sensors, thermal emitters, absorbers, laser generation, and the experimental capabilities of TP-liquid crystal devices are also discussed.

We demonstrate the facile exfoliation of transition metal dichalcogenides (TMDCs) directly in neat acrylate monomers resulting in readily processable stable colloidal dispersions-bypassing conventional methodologies that require process-limiting solvents and nanomaterial ligand functionalization. As such, we likewise demonstrate the controlled ease of fabricating polymer/TMDC nanocomposite thin films via free radical and anionic polymerization with minimal to no post-exfoliation processing. Our polymer/TMDC nanocomposite films offer tailored effective optical properties (i.e., effective refractive index, n eff , and effective extinction coefficient, k eff ) simply by adjusting the exfoliated TMDC colloidal dispersion concentration prior to thin film fabrication. Our nanocomposite films yield appealingly large changes in effective optical constants of up to similar to Delta 2.2 for n eff and similar to Delta 1.8 for k eff (as compared to neat polymer), which contrast is necessary to develop application-relevant optical coating systems. The direct exfoliation of TMDCs in neat monomers and the ease of thin film nanocomposite processing present alternative approaches for high-performance optical coating development with utility in sensing, imaging, and energy harvesting.

A novel class of photonic filters is obtained by integrating a large-area optical plasmonic metasurface with a broadband cholesteric liquid crystal (CLC) Bragg reflector. By utilizing the photo-thermal characteristics of the optical plasmonic metasurface, the reflection properties of the CLC layer can be manipulated. The thermally induced variation of the CLC's pitch and the refractive index produces a reversible blue-redshift of the reflection band of about 80 nm. The synergistic interaction between these two effects enables the development of innovative optical color filters that integrate a light-tunable mirror and a controllable optical absorber.

Curved electronics hold immense promise for applications ranging from flexible displays to biomedical devices. Transitioning from conventional planar fabrication to three-dimensional (3D) geometries remains a significant challenge. To manufacture 3D electronics, either the patterning process must be adapted to 3D forms, or planar substrates must be deformed into 3D shapes. Liquid crystal elastomers (LCEs) offer a promising platform by enabling intrinsic shape change from flat to intricate 3D forms through controlled molecular alignment. By patterning LCE surfaces with conductive traces prior to deformation, curved electronics can be fabricated using established planar deposition methods. Cross-linking LCEs with programmed molecular alignment at elevated temperatures allows for the fabrication of films that can adopt tunable normal and Gaussian curvature near room temperature. Increasing the nematic-isotropic transition temperature (T NI) of the LCE allows for a wide range of cross-linking temperatures, which in turn allows for the magnitude of the deformation to be controlled. Here, we present a tunable LCE composition with a T NI up to 162 +/- 2 degrees C. Moreover, we fabricate hemispherical films with radii of curvature ranging from 24.57 +/- 2.46 to 41.31 +/- 2.82 mm at room temperature. Additionally, the effect of metallization on the deformation of LCEs into 3D forms is characterized. We envision applications for this 3D electronic fabrication platform for wearable devices in health monitoring systems designed to integrate with curvilinear human anatomy.

The development of thin film materials for optoelectronic and meta‐optic applications requires the discovery of novel materials and reliable control over their optical constants during the growth process. In this work, localized laser oxidation and crystallization are used to tailor the optical constants of an amorphous MoS 2 precursor thin film. By scanning focused laser light across multiple films with varying intensity and speed in a controlled oxygen environment, the transient heating associated with this technique is used to control the localized oxidation of each film. Characterization of the laser‐processed regions results in synthesis phase diagrams indicating the laser conditions at which each oxide phase is formed. The optical constants of each phase are also measured, showing changes in refractive index Δ n and extinction coefficient Δ k as large as Δ n = 0.43 and Δ k = 0.35 for MoS 2 , Δ n = 1.7 and Δ k = 1.6 for MoO 3 , and Δ n = 1.7 and Δ k = 1.3 for MoO 2 . These changes are attributed to oxygen dopants, strain, improved crystallinity for MoS 2 , and oxygen vacancies and sulfur dopants for the oxide phases. These findings demonstrate the versatility of the laser processing approach for the highly controlled tailoring of thin film optical properties for high‐throughput materials discovery.

The newly designed triphenylamine (TPA) based asymmetric monomer (TPA-A) is synthesized for the development of a high-security information encryption system. TPA-A exhibits photoluminescence (PL) emission and redox-active electrochromic (EC) properties, highlighting its potential as a smart encryptable ink. Introducing a methyl group to one side branch of the TPA-A induces a steric hindrance effect, enabling TPA-A to form a self-assembled lamello-columnar structure. This structural modification reduces the phase transition temperature and simultaneously allows for the uniaxial orientation of TPA-A by a simple shear-coating process. The uniaxially oriented and self-assembled TPA-A thin films exhibits polarization-dependent PL properties and electrofluorochromic (EFC) characteristics combined with redox-responsive EC properties. The selective photopolymerization of polarization-dependent TPA-A thin film generates a dual-mode information encryption system. The newly developed EC smart film can open a new door for optoelectronic information encryption and anti-counterfeiting technologies.

The ability to tune fluorescence in polymer composites via 2D materials, dyes, or interfacial modifications provides a versatile platform for advancing optoelectronics as the underlying mechanisms offer control over emission properties, leading to innovative materials. In this work, 2D-white pearl (2D-WP) has been synthesized from naturally occurring WP. Liquid crystal polymer (LCP) composites based on liquid crystal (LC) monomer mixture E7 have been produced via 3D printing. 2D-WP has been dispersed in the LCP composite to demonstrate LC-2D interaction and generation of fluorescence. It has been shown that by introducing interfaces, a secondary emission can be obtained from 2D-dispersed LCP composites. The interactions between the four monomers in E7 and 2D-WP have been simulated, depicting a reduction in the original bandgap of 4.31 eV for 2D-WP to 2.5 eV for LCP-2D composite. In this way, 3D-printed LCP in combination with 2D-WP is shown to be an exciting prospect in further optical and photonics studies.

Fingerprint textures formed in chiral nematic liquid crystals can interact with light to generate complex, random transmitted or reflective patterns and can be used in several applications, optical devices, anticounterfeiting measures, tunable diffractive optics, and microfluidic devices. Here, we report the fabrication and properties of electrically controllable fingerprint textures and their associated diffraction patterns using polymer-stabilized cholesteric liquid crystals (FP-PSCLCs). While FP-CLCs exhibit different fingerprint textures each time an electric field is applied and removed, FP-PSCLCs stabilized with a small amount of polymer show the same fingerprint texture upon application and removal of a low AC voltage. Applying a sufficiently high AC voltage to FP-PSCLCs can induce random movement of ionic charges (i.e., hydrodynamic instability), leading to a different FP texture. The application of mechanical force to the FP-PSCLC sample can also induce a temporary texture independent of the electrically induced FP texture. In the absence of external stimulation, both the initial FP texture and the deformed temporary FP texture were observed to remain unchanged for several months, demonstrating a bistable behavior due to the memory effect of the polymer network of the FP-PSCLC.

We present the facile preparation of uniform nanocomposites of 2D nanomaterials in cholesteric liquid crystals using compatible materials. Here, we illustrate films with tunable and fixed optical properties that can be optimized to realize desired characteristics.

This study presents a simple theoretical model describing narrow envelope surface acoustic waves (phonons) and spin waves (magnons) in an ultrathin ferromagnetic film. Based on the general principles of weak wave turbulence, the model considers interactions between beams of an ideal phonon gas and a weakly non-ideal magnon gas, which represent magnetoacoustic oscillations in the system. Equations for the wave envelopes of phonons and magnons, along with their harmonics, are derived, incorporating nonlinear effects from three- and four-particle interactions. In the general non-resonant case, linear stationary envelope simulations are sufficient. These clarify the experimentally observed angular dependence of the transmitted acoustic signal with respect to the orientation of the magnetic field. The study highlights increased energy losses associated with enhanced magnetoacoustic coupling. Given the broad interdisciplinary interest in weak turbulence phenomena within condensed matter physics and nonlinear wave dynamics, our model offers significant predictive capabilities and greatly simplifies calculations of quasiparticle beam interactions.

Programmed assembly of natural materials on a large scale is often limited by inherent factors, including dimensional dispersity, complex hierarchical organization, and slow processing kinetics. In this study, we demonstrate a scalable strategy to preprogram the chiral assembly of cellulose nanocrystals (CNCs) by applying a rotational magnetic field during evaporation-induced self-assembly. To facilitate magnetic responsiveness, CNCs are decorated with magnetic nanoparticles and subjected to a rotational magnetic field. This magnetically induced azimuthal shear flow aligns the nanocrystals with a remarkably high local orientational order parameter of 0.96. On the macroscopic scale, the rotational flow generates a gradual, azimuthal alignment, resulting in large-area orientational ordering with identical helicity extending across centimeter-scale regions. Notably, the handedness of the chiral structure and the emergence of distinct optical textures, such as centimeter-wide Maltese crosses, can be controlled by adjusting the direction and strength of the induced large rotational magnetic vortex. This approach provides a versatile route for the larger-scale fabrication of programmable chiral photonic materials from bioderived building blocks.

To advance the development of an electrochromic (EC) smart glass, a π-extended viologen-based lyotropic chromonic liquid crystal (πV-LCLC) reactive mesogen (RM) is newly designed and successfully synthesized in this study. By extending the π-conjugation length of viologen, the πV-LCLC RM forms a stable LCLC phase at room temperature and retains its chemical integrity during the EC reactions, exhibiting reversible transitions across three redox states: dication (D), cation-radical (C), and neutral (N). A uniaxially oriented nanostructure is constructed on the macroscopic scale through shear-coating and molecular self-assembly. Subsequent photopolymerization of the uniaxially oriented πV-LCLC film significantly enhances its mechanical and chemical stability while enabling polarization-dependent transmittance and distinct color transitions. This newly developed πV-LCLC RM facilitates the fabrication of energy-efficient EC optical devices with tunable transmittance and multicolor modulation, and it is operable at a low voltage of 2.5 V.

The internet of things (IoT) has revolutionized society by creating a network of interconnected devices with sensors, processing ability and software for data exchange. However, the expansion of IoT places undue strain on energy resources. Thus, the development of low-power components is critical. Moreover, the demand for IoT has opened new markets for wearable technologies, necessitating innovations towards miniaturization. This rapid growth introduces further challenges in communication and environmental adaptability. Magnetoelectric (ME) microelectromechanical and nanoelectromechanical systems (M/NEMS) introduce unparalleled properties to reshape the IoT landscape. ME M/NEMS enable a 100,000× reduction in wavelength, resulting in reduced size and weight, and provide multifunctionality, such as simultaneous sensing, data transmission and wireless power transfer. With renewed interest in ME M/NEMS platforms, several disruptive technologies have emerged ranging from ultra-compact radiofrequency front-ends to quantum sensing, computing and communication networks. This Review delves into ME materials, ME composites and ME M/NEMS for IoT functions, including logic memory; magnetic sensing; wireless power transfer; ultra-compact antennas; power, radiofrequency and microwave electronics; and communication systems. Magnetoelectric (ME) microelectromechanical and nanoelectromechanical systems (M/NEMS) are vital for addressing the challenges of the internet of things (IoT) networks in size, energy efficiency and communication. This Review delves into ME materials and M/NEMS for IoT applications, such as sensing and communication technologies.