ACS Materials Letters最新文献

Recent developments in room-temperature phosphorescence (RTP) from biobased polymers have shown great promise in realizing sustainable RTP systems. Here, we introduce an efficient “top-down” method to achieve RTP biofibers using bamboo following partial delignification (B-fibers). The photophysical characterization combined with structural, surface, and chemical inquiries along with DFT calculations revealed the fundamental reasons for RTP, associated with the interactions between cellulose, hemicelluloses, and the residual lignin. Multiple emissive oxygen-containing clusters and aromatic chromophores in the B-fibers were shown to be RTP-active with a lifetime of 294.9 ms. The RTP emission of the B-fibers was found to be sensitive to temperature, excitation, and humidity. Moreover, when combined with a water-soluble fluorescent dye, red afterglow emission was demonstrated under the effect of energy transfer. Following these results, we synthesized functional luminescent materials (paper, films, textiles, and aerogels), proposed herein as practical, sustainable, and compostable choices for photoexcitation in the visible range.

In this study, we demonstrate the targeted insertion of additional Cu(II) into a hydrogen-bonded metal–organic framework, HMOF(Cu-atrz-nt), thereby achieving the in-situ modulation of hydrogen bonds (HBs) into coordination bonds (CBs) with virtually no alteration to the framework structure, converting HMOF(Cu-atrz-nt) into a purely coordinated MOF(Cu-atrz-nt). Significantly different from classical MOF-5 and ZIF-8, HMOF(Cu-atrz-nt) and MOF(Cu-atrz-nt) exhibit markedly stronger exothermicity along with truncated HB and CB characteristics and electronic properties, showing outstanding but distinct catalytic combustion effects on key propellant components such as RDX, HMX, CL-20, and AP. This study aims to enhance the comprehension of the weak interactions of framework materials while uncovering novel and exciting prospects for practical applications.

Bifacial perovskite solar cells (PSCs) can significantly enhance power generation by utilizing both front- and rear-side light, yet rear-side efficiency is often limited by reflection losses and environmental factors. A dual-functional organic–inorganic bilayer antireflective coating (ARC) composed of PMMA and MgF₂ was designed to improve both bifaciality and device stability. Three-dimensional finite-difference time-domain (FDTD) simulations optimized the ARC thickness, achieving a 2.37% increase in the rear-side transmittance. The champion cell demonstrated a front-side efficiency of 24.12%, a rear-side efficiency of 21.37%, and 88% bifaciality. Under simulated sand conditions (20% rear-side reflectance), the equivalent bifacial efficiency reached 28.33%. Additionally, the bilayer ARC effectively blocked moisture and oxygen ingress, enhancing device stability under high-humidity and high-temperature conditions, making these PSCs ideal for environments with varying reflectance.

The pervasive threat of microbial infections, compromising human health, compounded by the rising incidence of multidrug-resistant bacteria, has underscored the urgent need for the development of innovative antimicrobial strategies. Nanomaterials have garnered substantial attention as alternative antimicrobial materials, owing to their remarkable chemical and physical properties. Despite the prominent bactericidal activity of these nanomaterials, some studies have proposed otherwise, suggesting that certain nanomaterials can potentially trigger the evolution of antimicrobial resistance (AMR). Therefore, it is urgent to elucidate the underlying mechanism governing the dual characteristics of antimicrobial nanomaterials. This Review commences by providing an overview of the antimicrobial properties of three distinct nanomaterials. Subsequently, it delves into the primary inactivation mechanisms and analyzes the physicochemical factors influencing their antimicrobial activity. Concurrently, the impact of molecular initiation events on AMR evolution via nanomicrobe interactions is systematically elucidated, enabling the proposal of four guiding design principles to mitigate AMR evolution.

Porous organic cages with intrinsic and extrinsic cavities offer excellent host–guest control, molecular uptake, and on-demand release without compromising the selectivity. However, dynamic control over the porosity in cage molecules remains challenging. Herein, we report a CC3 cage-based crystalline adsorbent with dynamic control over its porosity for stable adsorption and release of the probe organic molecules. Interestingly, the polymorphic forms of cages (α and β) differ in crystallographic packing with flexible orientation but retain their structure after solvation. Using this isomorphism, the CC3 adsorbent exhibited an uptake of 29.5 mg g^–1 for neutral red, 39.5 mg g^–1 for methyl blue, and 39 mg g^–1 for both molecules. The solvent-induced phase transition selectively obstructs neutral red adsorption with 85.5% change in overall capacity. Adsorption affinity correlates strongly with surface area, while solvent choice governs selectivity, highlighting switchable porosity. These findings enable advanced adsorbents with switchable porosity and selective affinity for energy and environmental applications.

4D printing enables three-dimensional structures to respond dynamically to external stimuli, significantly expanding their functional potential. While most hydrogel-based 4D printing using femtosecond laser two-photon polymerization focuses on material functionalization and structural design, little attention has been given to achieving intelligent deformation by modifying the scanning strategy. Inspired by the layered architecture of butterfly wings, we introduce a novel approach to fabricate diverse convoluted deformation structures. By combining morphological and mechanical property analysis with a two-photon one-step 4D printing strategy, we demonstrate precise control over deformation behavior. Furthermore, we showcase the ability to fabricate customized deformation structures on demand employed for actuation and sensing by adjusting scanning methods. This simple and flexible one-step 4D printing method represents a significant advancement in micro- and nanoscale sensing and fabrication, offering new possibilities for responsive hydrogel systems.

High-temperature photothermal response functional materials are an important branch of advanced photothermal materials. However, pure organic high-temperature photothermal materials are currently relatively scarce, and their molecular design and synthesis are challenging. In this research, a highly efficient [2 + 2] cycloaddition–retroelectrocyclization reaction has been carried out between the precursor molecule containing N,N-diphenyl-4-(phenylethynyl)aniline and piperazine-2,5-dione units (TP) and the typical electron-deficient unit 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (4F-TCNQ), and a rigid and twisted high-temperature photothermal organic material (named TTP) has been successfully designed and synthesized. This material is easy to synthesize and solution-processable, has broad spectral absorption (320–1900 nm), and can be triggered for high-temperature (∼400 °C) photothermal response by a near-infrared region II (NIR-II) laser (1064 nm). It has also been successfully applied to laser ignition, the construction of high-temperature shape memory actuators, and photowelding of metals with a 1064 nm laser, demonstrating the attractive potential for high-temperature NIR-II photothermal applications.

This paper provides a comprehensive overview of high-entropy oxides (HEOs) and their applications in photocatalysis. The unique functionality of HEOs stems from their distinct crystal and electronic structures, achieved through the substitution of one cation with multiple cations in the lattice. This structural innovation has attracted significant attention, with increasing studies since 2019. To date, approximately 38 papers on HEOs in photocatalysis have been reported, indicating that this research is still in its early stages. Some HEOs exhibit photocatalytic performance comparable to that of conventional oxides like TiO₂ and SrTiO₃, highlighting their potential. This Perspective discusses the synthesis methods, crystal structures, and photocatalytic properties of HEOs, emphasizing their advantages through specific examples. Additionally, it proposes future research directions, including the development of innovative materials and prediction of properties using first-principles calculations and machine learning, to advance the application of HEOs in photocatalysis.

Growing environmental concerns have driven the search for sustainable wastewater treatment solutions, particularly for the removal of persistent synthetic dyes. This study explores hydrogels made from squid pen protein (SPP) and chitosan, biodegradable polymers, for anionic dye adsorption─reactive blue 4 (RB4) and methyl orange (MO). A 50%/50% SPP/chitosan hydrogel was optimal for RB4 adsorption while minimizing chitosan use. Adsorption followed the Langmuir model, with capacities of 151.52 mg/g for RB4 and 54.94 mg/g for MO. Optimal RB4 adsorption conditions were 65 °C, 6 h, pH 7, and 0.2 wt % adsorbent at 300 rpm. Kinetic analysis indicated a pseudo-second-order model, suggesting chemisorption. Characterization (Fourier Transform Infrared Spectroscopy - FT-IR, Scanning Electron Microscopy - SEM, X-ray Photoelectron Spectroscopy - XPS) revealed functional groups and binding mechanisms, with XPS confirming a nucleophilic attack from the between amino groups of chitosan/SPP protein and the dichlorotriazine moiety of RB4. Higher cross-linker content reduced adsorption. This study demonstrates SPP/chitosan hydrogels as a cost-effective and sustainable alternative for wastewater treatment.