Materials Chemistry Frontiers最新文献

In this study, we explored the use of two 3D printing techniques, direct ink writing (DIW) and digital light processing (DLP), as novel and flexible strategies to control the 3D geometry and morphology of functional materials. To demonstrate their potential, different types of carbon nitride (C₃N₄) were combined and successfully printed with various polymers, such as methylcellulose (MC) and polysulfone (PSF). C₃N₄ is a metal-free photoactive material, which has recently gained significant interest due to its attractive optoelectronic properties. The 3D printed C₃N₄-based composites were tested in typical potential applications for their photo-, piezo- and electrocatalytic activity. Tailored formulations and design strategies were devised for pollutant photo- and piezoelectric degradation as well as electrochemical sensing, showing the effect of the formulation on the performance of the 3D printed C₃N₄ polymer composites. The performance evaluations revealed promising results, complemented by the stability of the 3D printed geometries in organic solvents commonly used in chemical syntheses. Specifically, the DIW g-C₃N₄/PSF formulation showed the highest overall pollutant removal (71%), followed by the DLP g-C₃N₄-based formulations which showed high removal efficiencies (up to 63%) with a high level of piezoelectric degradation (up to 41%). In addition, Piezoresponse Force Microscopy (PFM) analysis of both the starting bulk g-C₃N₄ powder and DIW 3D printed bulk g-C₃N₄/MC composite revealed significant piezoelectric properties, broadening their potential applications.

Rational design and structural modulation of MOF materials are crucial to developing high-performance supercapacitor electrodes. In this research study, high-performance bimetallic MOF supercapacitor electrode materials have been successfully fabricated via a cerium-induced strategy. The addition of cerium not only adjusts the morphology of the Co-MOF but also enhances the oxygen vacancy defects. Notably, the Co₄Ce₁-MOF material possesses a unique nanorod-like morphology, which greatly increases the specific surface area, shortens the ion transport routes and exposes more active sites. Meanwhile, the higher oxygen vacancy concentration in the Co₄Ce₁-MOF suggests its more pronounced oxygen vacancy defects compared to the Co-MOF. These findings provide an innovative strategy for the fabrication of MOF-based high-performance electrode materials for supercapacitor applications.

Circularly polarized room-temperature phosphorescence (CPRTP) materials integrating room-temperature phosphorescence (RTP) and circularly polarized luminescence (CPL) show great promise for frontier applications like optoelectronics. Herein, we report a chiral luminophore Ben-2Chol, which can self-assemble into micrometer-scale sheets in the aggregated state of solution and spin-coated films and achieve circularly polarized fluorescence (CPF) through aggregation-induced chirality transfer, with the maximum g_lum reaching −1.1 × 10⁻³. Notably, its liquid-phase-diffused fibrous microcrystals exhibit CPRTP with inverted polarization relative to the sheets, featuring g_lum values of +6.0 × 10⁻³ (blue) and +1.0 × 10⁻³ (yellow-green) with a 41.7 ms of luminescence lifetime. Mechanical grinding eliminates RTP/CPL, confirming crystallization-induced properties. This study provides a simple strategy for constructing CPRTP materials through aggregation-induced chirality transfer in microcrystals, offering new insights for the design of chiral luminescent materials with dual functionalities.

Organic photosensitizers with long-wavelength absorption, photostability and tumour specificity are highly desired in photodynamic therapy (PDT), but the molecular design for this three-in-one formula is quite challenging. Herein, we report the molecular engineering of a series of expanded porphyrinoids with N-anisyl dithienopyrrole (DTP) and meso-pentafluorophenyl substituents to collectively accelerate the reactive oxygen species (ROS) generation. Due to extensive π-conjugation, the Q-bands are significantly red-shifted, extending into the near-IR region. Hence, this series of molecules can be photoactivated using the deeply penetrating 808 nm laser. Interestingly, subtle tuning of singlet oxygen production could be achieved by increasing the number of meso-pentafluorophenyl pendants. This was corroborated via photophysical and theoretical studies, which suggested altered electron distribution and stabilization of energy levels for rubyrins with four pentafluorophenyl substituents. On the contrary, heptaphyrin with its increased π-electrons exhibited no ROS generation due to the mismatch in energy gap with molecular oxygen. The photodynamic properties of these macrocycles and their respective nanoparticles, including their remarkable ROS generation, exceptional photostability and biocompatibility, demonstrate their potential as excellent candidates for PDT. The in vitro experiments substantiate the effective anticancer activity of these nanoparticles, offering future potential opportunities for application via in vivo PDT and bioimaging.

The majority of current research on organic room-temperature phosphorescence (RTP) materials focuses on film or powder forms, with limited exploration into the fabrication of complex 3D structures with high precision and enhanced RTP properties. Herein, a general strategy is proposed to construct 3D RTP models with precise structures and ultralong lifetimes by micro-doping carbazole-based chromophores into photocurable standard resins (SRs) and combining them with photocurable 3D printing technology. The highly cross-linked and rigid microenvironment formed after the curing of SRs endows the carbazole-doped SRs with a long RTP lifetime of up to 1.8 s. Utilizing digital light processing 3D printing technology, a series of multidimensional RTP models with precise structures and ultralong lifetimes are constructed based on these carbazole-doped SRs. Given the superior tunability of 3D printing blueprints and the excellent RTP properties of the printed models, these multidimensional models demonstrate great application prospects in advanced anti-counterfeiting and encryption applications.

Covalent organic frameworks (COFs) have gained significant research attention as promising proton conducting materials due to their prominent properties such as remarkable specific surface area, regular structure and minimal density. Herein, a series of polyethyleneimine (PEI) functionalized COFs (TpPa–SO₃H@PEI-wt%) with high amino density were designed and synthesized to promote the proton hopping in COF hexagonal nanopores, where flexible polyethyleneimine (PEI) has strong proton capture and release capabilities, which can improve the continuity of the hydrogen-bonding networks and provide a low energy barrier pathway for proton hopping in the system, and thus improving proton transfer efficiency. Importantly, the proton conductivity can be well modulated by varying the molecular weight and grafted amount of PEI, among which, TpPa–SO₃H@PEI₆₀₀-40% exhibited a remarkable proton conductivity as high as 5.9 × 10⁻³ S cm⁻¹ along with a low activation energy of 0.14 eV at 98% RH and 80 °C, thanks to the Grotthuss mechanism for proton conduction. In addition, TpPa–SO₃H@PEI₆₀₀-40% showed excellent stability in the water vapor environment and no obvious conductivity decrease was observed even after 72 hours of continuous conductivity measurements. This demonstrates its good potential for the development and application of high proton conductive materials.

Nanozymes with peroxidase (POD)-like activity hold great promise for in situ nanovaccines to activate antitumor immunity through immunogenic cell death (ICD). However, their efficacy remains limited due to suboptimal reactive oxygen species (ROS) generation and the immunosuppressive tumor microenvironment (TME). To address this, we herein constructed a high-entropy nanozyme (HEzyme) using a Prussian blue analog (PBA) as the platform. The HE mixing state induced lattice distortion and d-orbital modulation, endowing the PBA-based HEzyme with an enhanced POD-like activity and an exceptional photothermal conversion efficiency of 82.96%. This dual functionality enabled photothermal-adjuvant ROS amplification for triggering robust ICD-driven anti-tumor immunity. Simultaneously, the HEzyme reprogrammed tumor-associated macrophages from immunosuppressive M2 to antitumor M1 phenotypes, reversing TME immunosuppression. In 4T1 tumor-bearing mouse models, the HEzyme-based in situ nanovaccine achieved dual suppression of primary and distal tumors. This work presents an innovative paradigm for engineering nanozyme-based in situ nanovaccines by introduction of HE into PBA, bridging photothermal intervention, ICD induction, and TME remodeling to potentiate tumor immunotherapy.

The development of efficient red-emitting tin hybrid halides that display a large Stokes shift and zero self-absorption is highly desirable because of their tremendous potential in solid-state lighting and anticounterfeiting applications. However, such materials are difficult to obtain and have rarely been reported. Herein, we present a layered tin halide hybrid, (C₄H₁₂N₂)₂[SnCl₆], in which crystallographically independent [SnCl₆] octahedra alternate with organic bilayers. Remarkably, (C₄H₁₂N₂)₂[SnCl₆] shows bright red emission with a large Stokes shift of 3.04 eV and a high photoluminescence quantum yield (PLQY) of 70%. Structural analyses reveal that the large Stokes shift and high PLQY stem from the compact lattice, shortened Sn⋯Sn separations, and low dimensionality, which together enhance radiative recombination while permitting greater structural relaxation in the excited state. Consequently, (C₄H₁₂N₂)₂[SnCl₆] is an excellent red phosphor with promising prospects for application in white light-emitting diodes and anti-counterfeiting technologies. In short, this study elucidates the structure–property–application relationships of tin hybrid halides, paving the way toward high-performance emissive metal-halide materials.

Various reactions and systems that respond to hydrostatic pressure, i.e., one type of mechanical isotropic stimulus, have been developed over the past decades. Here, we show that a one-electron (1e) reduction of dicationic cyclophane can be realised by applying hydrostatic pressure in a water-containing solvent. The large negative value of the volume change observed for this reduction, which is key to inducing the reduction reaction, is due to the desolvation of the H₂O molecules and the change in the proximity between the cyclophane π units accompanied by a decrease in electrostatic repulsion. In fact, related monocations did not undergo a 1e reduction under hydrostatic pressure, even in water-containing solvents, indicating that the reduction behaviour is enabled by the cyclophane structure. Furthermore, in the case of weakly polar anions such as BF₄⁻ and PF₆⁻, a change in the solvation/desolvation of the H₂O molecules of dicationic cyclophanes can occur upon hydrostatic pressurisation, leading to a 1e reduction, showing that the reduction behaviour can be tuned by selecting the appropriate counter anion. Therefore, this study provides a valuable strategy and guidelines for the rational design of molecules with redox behaviour that can be modulated using hydrostatic pressure.

Improving the efficiency of environmentally friendly energy sources such as solar energy is one of the basic objectives for developing the ecological transition required by our society. Thus, in this work, nanofluids based on NiO nanowires and a polydimethylsiloxane (PDMS) fluid are developed to improve the efficiency of parabolic trough-based concentrating solar power plants (CSP-PTC). To this end, NiO nanowires are successfully synthesized in our laboratory and used to prepare nanofluids. Their physical stability is thoroughly characterized. Subsequently, the properties of interest for the application of these nanofluids as heat transfer fluids are characterized. These properties were surface tension, density, dynamic viscosity, isobaric specific heat and thermal conductivity. Based on these properties, the efficiency improvement of CSP-PTC systems is estimated, achieving improvements of up to 5% with the designed nanofluids.