Materials Advances最新文献

Liquid crystal elastomers (LCEs) are versatile materials capable of reversible, large-scale deformations in response to external stimuli. The orientation of the liquid crystal mesogens within the polymer network significantly impacts their performance in various applications, including soft robotics and actuators. Here, we present a simple, cost-effective surface-induced alignment technique using off-the-shelf, commercially available Kapton HN films, which—unlike previously reported custom polyimide coatings—inherently possess surface features capable of inducing mesogen alignment and can also be mechanically rubbed to enhance the density and uniformity of surface nanogrooves. This enables the fabrication of monodomain LCE films with controlled alignment through a straightforward mechanical rubbing process, representing a significant advancement in accessibility and scalability compared to prior methods. Atomic force microscopy (AFM) reveals that surface rubbing alters the topography of Kapton films, with rubbing in different directions resulting in distinct roughness profiles. Polarized optical microscopy (POM) analysis of LCE films aligned using this technique demonstrates that rubbing Kapton horizontally or vertically leads to varying degrees of mesogen alignment, with horizontal rubbing producing the highest alignment quality. Thermal actuation tests confirm that the alignment configuration significantly influences the LCE's actuation response, with the planar-aligned films exhibiting uniaxial contraction and twisted-aligned films demonstrating bending behavior due to through-thickness strain mismatch. This mechanistic correlation between surface morphology, mesogen orientation, and actuation behavior offers new insights into alignment-driven deformation in LCEs. This technique offers an accessible and reproducible method for fabricating aligned LCEs, which can be beneficial for early-stage research and educational purposes in soft material design and fabrication.

A comprehensive simulation-based investigation was conducted on an advanced, lead-free perovskite solar cell (PSC) design. This cell achieved high performance through its novel absorber architecture, which utilized a dual-layer configuration made of tin-based perovskite materials (CsSnI₃ and CsSnCl₃). Simulations were carried out to determine device performance and stability limits by employing the SCAPS-1D software tool. The device structure was designed to enable bandgap alignment with CsSnI₃, which was used as a narrow bandgap material to act as a light harvester, and CsSnCl₃, which was used as a wider bandgap material to act as a charge and defect passivation layer. Prior to the simulations, necessary material parameter details, such as the orbital components forming the band edges and bandgap widening, were thoroughly verified. RIGOROUS simulations on SCAPS-1D revealed a maximum power conversion efficiency (PCE) value of 30.02% (FF = 88.56%, J_sc = 32.09 mA cm⁻², and V_oc = 1.05 V) when optimal parameter inputs were used. Important stability constraints on various PSC devices were obtained by precisely modelling the defects, which resulted in PCE failure when either the interface defect density value and/or the respective bulk density value of either CsSnI₃/CsSnCl₃ layer exceeded 1 × 10¹⁵ cm⁻³. Therefore, high-quality materials are mandatory. In addition, thermal stability analysis indicated that the PCE value is inversely related to temperature. Importantly, the analysis indicates that the voltage component V_oc influences the PCE value predominantly.

This study presents a facile, eco-friendly, and controlled reline-assisted chemical reduction method to synthesize fcc-hcp Ni/Ni(OH)₂ nanocomposites. The conventional chemical reduction process was modified by replacing water with reline to produce the Ni/Ni(OH)₂ nanocomposite (Ni-reline). The incorporation of precursor salt in reline significantly influenced its physicochemical properties. Specifically, the optimized concentration of nickel salt in reline (0.4 mol dm⁻³) reduced its viscosity from 573 cP to 57 cP and increased its conductivity, which played a crucial role in the nucleation and growth of nanoparticles. As a consequence, coral reef-like nanostructures (∼39 nm) developed in reline, whereas in aqueous media, spherical Ni nanoparticles (Ni-Aq.) with a significantly larger particle size (∼92 nm) were formed. Elemental analysis further confirmed the presence of carbon in Ni-reline, derived from the DES matrix. Ni-Aq. and Ni-reline were evaluated as catalysts for the reductive hydrogenation of 4-nitrophenol to 4-aminophenol. Ni-reline exhibited superior catalytic activity, achieving 95% conversion in 20 minutes with a rate constant of 0.1336 min⁻¹, 11 times higher than Ni-Aq. This enhancement is attributed to the mixed-phase structure, increased surface area, and surface-bound carbon species promoting adsorption and electron transfer. Moreover, Ni-reline demonstrated excellent reusability over five consecutive cycles due to easy magnetic separation with minimal catalyst loss. This study highlights the potential of reline to modify nanostructure growth and phase behavior for efficient, environmentally friendly catalytic applications.

Single-crystals composed of organic π-conjugated molecules with high solid-state luminescence are promising candidates for laser media. Among them, trans,trans-1,4-distyrylbenzene (DSB) derivatives are particularly attractive due to their high photoluminescence and are frequently employed in systems of laser media and amplified spontaneous emissions (ASE). Although numerous DSB derivatives have been designed for single-crystal laser applications, achieving high solid-state luminescence remains challenging because of the difficulty in predicting and controlling aggregation motifs. We report herein a chemical structure design strategy based on fluorination of DSBs to achieve ASE. The fluorination at the central phenylene of DSB effectively inhibited intermolecular CH–π interactions. In contrast, the fluorination at the α- or β-position in the vinylene unit did not suppress such interactions, resulting in CH–π interaction-driven herringbone packing. The fluorinated DSBs exhibiting herringbone packing in the crystal-state demonstrate ASE due to the high luminescence performance based on the small intermolecular overlapping of their π-orbitals.

The demand for sustainable energy has been increasing, driving the exploration of novel materials for sustainable energy-harvesting technologies. The present study explores a triboelectric nanogenerator (TENG) based on microbial cellulose (MC), synthesized by symbiotically cultured bacteria and yeast (SCOBY), as a positive triboelectric material, and fluorinated ethylene propylene (FEP) as a negative triboelectric material. The MC film synthesized by a simple fermentation method exhibits very high porosity and a highly rough surface, making it an excellent triboelectric material. The fabricated TENG exhibits an open-circuit voltage (V_oc) of ∼620 V, a short-circuit current (I_sc) of ∼40 µA, and a power density of 16.5 W m⁻² at a 10 MΩ load resistance, demonstrating its superior performance compared to reported bacterial-cellulose-based TENGs. Moreover, the synthesized MC film exhibits efficient antibacterial activity against Gram-negative and Gram-positive bacteria, without the need for an additional antibacterial agent. This study fills a gap in research into clean and green energy harvesting using MC, creating an opportunity for novel, environmentally-friendly TENGs. Practical applications, such as powering a calculator, validate the potential for commercial use of innovative TENG technologies.

In our quest to replicate the full spectrum of natural daylight, which creates comfortable and visually stimulating reading environments, we have engineered a novel single-component phosphor based on divanadate compounds. Traditional broadband yellow-emitting rare-earth garnet systems often underperform due to insufficient emission in the red and cyan regions, delivering light with noticeable spectral gaps and cooler tones that can strain the eyes during prolonged reading. This tailored approach replaces rubidium with cesium and strategically incorporates bismuth into the Rb_3−xCs_xYV₂O₈ matrix, inducing fine crystal field modifications that boost luminescence intensity and generate a warm white emission. The altered light output effectively minimizes the drawbacks of multi-phosphor assemblies, offering a streamlined solution that overcomes issues such as high correlated color temperatures and poor color fidelity. The Cs₃Bi_0.25Y_0.75V₂O₈ composition exhibits high thermal stability, retaining 75% of its emission intensity at 423 K, with a robust activation energy of 0.32 eV. When integrated into LED devices, the phosphor demonstrates a remarkable ability to shift the white emission from cooler (Cs₃YV₂O₈: CCT ≈ 6111 K, CRI ≈ 78) to warmer hues (Cs₃Bi_0.25Y_0.75V₂O₈: CCT ≈ 4887 K, CRI ≈ 79). In particular, the rare-earth-free Cs₃BiV₂O₈ composition-based white LED emits white light CCT ≈ 4662 K, closely emulating the soft, balanced glow of natural sunlight. Such spectral tuning enhances visual clarity and minimizes eye fatigue, creating an inviting atmosphere ideal for reading rooms and workspaces. This study underscores the potential of precise crystal engineering and controlled doping strategies in developing high-performance lighting solutions that set a new benchmark for indoor illumination, mirroring the natural radiance of the sun.

Surface functionalization of graphitic carbon nitrides has been demonstrated to promote catalytic properties but has rarely been investigated with the 2D carbon nitrides poly(heptazine imide) (PHI) and poly(triazine imide) (PTI) despite their potential for a variety of applications. This may originate from the chemically inert and hence unreactive character of carbon nitrides in conjunction with the lack of possibilities to verify the success of a post-synthetic covalent functionalization. Herein, we address these problems and mainly investigate the possibility of covalently functionalizing PHI with any desired organic molecule. A strategy of using fluorine-containing functionalizations to enable access to ¹⁹F NMR studies is utilized, which ensures the complete removal of unreacted functional groups (FGs) and provides an easy and reliable quantification of the functionalization afterwards. Screening experiments illustrate the necessity to increase the accessibility to the surface. Furthermore, a high yield can be achieved by using acyl chlorides as functionalization agents. In addition, the proof of covalent functionalization is provided by means of 2D NMR on ¹⁵N-enriched PHI modified with a ¹³C-enriched FG. Our study thus presents a general route to the covalent functionalization of PHI and opens up new perspectives for rationally adding desired functionality to polymeric carbon nitrides in general.

Organofunctional silanes have garnered significant attention in materials science and nanotechnology due to their ease of use, rapid reactivity, and superior performance in adhesion, crosslinking, surface modification, moisture scavenging, and rheological enhancement. However, incorporating carboxyl functionality into alkoxysilanes remains challenging, largely due to their chemical instability arising from acid-catalyzed hydrolysis and intramolecular ring formation via O-acylation. In this work, we introduce an ultra-stable carboxyl silatrane (COOHSiT) engineered for controlled silanization to form thin, uniform, and functional organosilicon layers tailored for biosensor applications. The unique silatrane architecture characterized by a robust tricyclic cage and a stabilizing transannular N→Si dative bond imparts exceptional hydrolytic stability, preserving structural integrity throughout the organic synthesis and long-term storage, as confirmed by nuclear magnetic resonance (NMR) spectroscopy. Surface deposition of COOHSiT on silicon wafers was characterized using ellipsometry, contact angle goniometry, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The resulting films exhibited excellent uniformity and well-controlled thickness, attributable to the precise silanization and intermolecular hydrogen bonding between amide groups. Importantly, the COOHSiT coatings maintained accessible and reactive carboxyl groups, enabling efficient downstream functionalization via EDC/NHS chemistry for antigen/antibody conjugation. This platform was successfully employed for neurofilament light chain (NfL) detection using a fiber-optic nanogold-linked immunosorbent assay (FONLISA), achieving an impressively low limit of detection (LOD) of 0.56 fM. Altogether, COOHSiT emerges as a highly functional and stable organosilicon building block, opening new avenues for the development of advanced functional nanomaterials and biosensing technologies.

Correction for ‘A three-dimensional ZnO/TUD-1 nanocomposite-based multifunctional sensor for humidity detection and wastewater remediation’ by Aryan Boora et al., Mater. Adv., 2024, 5, 4467–4479, https://doi.org/10.1039/D4MA00191E.

Correction for ‘Efficient photo-oxidation of bisphenol a and tetracycline through sulfur-doped g-C₃N₄/CD heterojunctions’ by Ankoor Sura et al., Mater. Adv., 2024, 5, 5514–5526, https://doi.org/10.1039/D4MA00270A.