Materials Chemistry Frontiers最新文献

Bacterial infections caused by drug-resistant bacteria have become a significant health challenge in the 21st century. Photodynamic therapy (PDT), a novel approach for treating drug-resistant bacterial infections, has attracted considerable attention due to its broad-spectrum antimicrobial activity, non-invasive, and highly selective advantages. However, the “always on” nature of conventional PDT often leads to unintended damage to surrounding healthy tissues. To address this issue, stimuli-responsive photodynamic therapeutic (SRPT) platforms with adjustable antibacterial activity have been developed. These SRPT platforms remain inactive in normal tissues and are only triggered to exhibit antimicrobial activity under specific stimuli at the targeted site. This review comprehensively summarizes the contributions of SRPT platforms to the treatment of bacterial infections over the past few years and offers insights into their future development. Specifically, this review delves into the design mechanisms and the latest advancements of SRPT platforms in combating bacterial infections. Particular emphasis is placed on key factors such as pH, redox status, enzymes, and dual-stimulation as the primary design directions for activation strategies.

Perovskite solar cells (PSCs) have garnered significant attention owing to their solution fabrication, cost-effectiveness, and high power conversion efficiency, yet their practical application has been hindered by instability issues. Under operational conditions, redox reactions have been found to be prevalent in perovskite devices, but the underlying mechanism remains very unclear. Here, we systematically investigated the impact of light irradiation, atmosphere and interfacial structures on the redox kinetics in PSCs. Our results show that oxygen acts as a predominant factor driving device degradation, other than the transport layer or spectral components. Spectroscopic results reveal that the formation of iodine-related defects, e.g., triiodide ion (I₃⁻) and iodine (I₂), are dramatically boosted under oxygen-rich conditions, and can be further accelerated by light exposure. These findings provide critical insights into the redox reaction mechanism of perovskite-based materials, and offer a potential direction for enhancing the long-term stability of PSCs.

We present the synthesis and comprehensive characterization of a new class of hybrid inorganic–organic materials: polyhedral oligomeric silsesquioxane (POSS) cages functionalized with 1-haloacetylene groups (Cl, Br, I). These building blocks undergo a unique, catalyst-free, solid-state thermal polymerization. This process results in highly cross-linked poly(1-haloacetylene) networks. The resulting polymers—polyPOSS-C₂Cl, polyPOSS-C₂Br, and polyPOSS-C₂I—exhibit direct optical band gaps of 2.79, 2.74, and 2.38 eV, respectively, and maintain the structural integrity of the POSS core, as confirmed by solid-state NMR (¹³C, ¹⁵N, and ²⁹Si), DRIFT, Raman, and PXRD analyses. Kinetic studies indicate pseudo-second-order polymerization with activation energies between 179 and 217 kJ mol⁻¹. These materials are completely insoluble in common solvents and thermally stable up to 309 °C. Their robust structure, high thermal resistance, and semiconducting properties highlight their potential for advanced optoelectronic applications.

Mn⁴⁺-activated phosphors are widely used in plant lighting due to their efficient far-red emission (600–760 nm). However, their narrow emission bandwidth limits their applications. To address this, we co-doped Fe³⁺ with a broadband far-red/near-infrared (NIR) emission (650–900 nm) with Mn⁴⁺ in a spinel-structured MgAl₂O₄ host. This strategy synergistically combines the luminescence characteristics of both ions to achieve a broadened spectral output. Upon 285 nm ultraviolet excitation, the Fe³⁺/Mn⁴⁺ co-doped MgAl₂O₄ system exhibits a dual-peak broadband emission spanning 600–900 nm, with emission maxima at 655 and 722 nm. Notably, the full width at half maximum (FWHM) reaches 132 nm, representing a 109% increase relative to the Mn⁴⁺ singly doped sample (FWHM = 63 nm). The dual-peak broadband emission is highly consistent with the absorption bands of the two types of phytochrome (Pr and Pfr). This spectral matching enables bidirectional control of the phytochrome photoconversion cycle. This work establishes an innovative strategy for developing broadband far-red phosphors that dynamically regulate phytochrome activity to advance precision plant lighting.

Paper—an essential carrier for information dissemination and the inheritance of civilization—holds significant importance in both daily life and specific applications. Nevertheless, the acidification of paper reduces its mechanical strength, restricts its functionality, and considerably shortens its service life. In this research, a handmade acid-free paper (HMAP) with an initial pH of 7–8 was prepared by incorporating ultrathin magnesium–aluminum layered double hydroxide (LDH) nanosheets as a filler in the paper preparation process. The Mg–Al LDH nanosheets, with an average layer thickness of about 8 nm, were synthesized via a one-step surfactant-assisted hydrothermal method. Simultaneously, the HMAP exhibits the advantages of long service life and acid resistance after a prolonged accelerated aging experiment (two months), maintaining a pH above 6. Additionally, the HMAP also possesses potential application value in some domains such as flame retardancy and adsorption. This work substantiates the feasibility of ultrathin LDH as a paper filler and broadens its prospects in the preparation of acid-free long-life paper.

The efficiency of perovskite solar cells is constrained by surface and bulk recombination, along with poor band alignment at the interfaces of the transport layers. In our study, we demonstrate that modifying the surface and grain boundary (GB) of perovskite using tetraphenylethylene-enamine (TPE-en) enhances band alignment at the perovskite-hole transport layer interface and mitigates recombination within the perovskite material. By leveraging the solubility of small organic molecules in orthogonal solvents, we introduce TPE-en onto the perovskite surface akin to anti-solvent methods. Our investigation reveals a significant enhancement in the short circuit current density, fill factor, and open circuit voltage of the surface-modified (SM) perovskite. Specifically, we achieve a total power conversion efficiency of 18.73% (MA_0.9AA_0.1PbI₃). Comparative analyses show TPE-en outperforms other reported TPE derivatives in device performance. Through systematic interface analysis, we observe that TPE-en effectively reduces surface and GB defects by elevating the HOMO levels of the perovskite, introducing an interface dipole at the perovskite-spiro-OMeTAD interface. Optical measurements such as time-resolved photoluminescence, Ultraviolet photoelectron spectroscopy, and X-ray photoelectron spectroscopy were used to investigate the cause of this improvement. A 0.28 eV surface dipole formed provided effective band alignment, resulting in enhanced hole extraction and photovoltaic performance.

Afterglow carbon dots have attracted a lot of attention due to their unique advantageous properties, such as high sensitivity and resistance to interference from background light. However, achieving dual-mode afterglow emission from the single-mode afterglow of carbon dots remains a challenge. Here, we achieved the induction of a carbon dot afterglow emission mode through solvent effects. In this method, boric acid is used to construct a rigid plane to suppress the non-radiative transition of triplet excitons, and the afterglow of carbon dots can be changed from dual-mode emission, to single-mode emission to no afterglow emission under H₂O, DMF and MeOH environments during the synthesis. Notably, the solvent contains different hybrid forms of the nitrogen element, which have different effects on the delayed fluorescence: sp² hybrid nitrogen causes the delayed fluorescence to disappear and sp hybrid nitrogen induces a slight increase in delayed fluorescence. Meanwhile, doping with N effectively improves the quantum yield of CDs@BA. Finally, carbon dots with different afterglow properties were obtained in different solvent environments and applied in temperature sensing and anti-counterfeiting. This work provides a design idea and a feasible strategy to construct carbon dots with different afterglow properties.

Developing supramolecular network materials with controllable phosphorescence behavior constitutes a highly active research frontier. Herein, the preparation of a high-efficiency room-temperature phosphorescence (RTP) supramolecular polymer network (SPN) via the post-polymerization assembly strategy is reported, through sequential polymerization of naphthalimide pyridinium derivatives and spontaneous aqueous self-assembly with exfoliated LAPONITE® (LP) nanosheets. Initially, thermally initiated copolymerization of cationic naphthalimide pyridinium derivatives with acrylamide produces transparent swollen hydrogels by solvent replacement, exhibiting emergent RTP with a lifetime of 29.1 μs governed by hydrogen-bonding confinement. Subsequent electrostatic integration of negatively charged LP nanosheets into hydrogels can tightly anchor cationic naphthalimide pyridinium moieties, thus extending the phosphorescence lifetime to 923 μs by further suppressing the non-radiative transition of triplet excitons. Crucially, dual spatial confinement—from both interwoven hydrogen-bonding networks coupled with rigid LP nanosheet architectures—synergistically elevates the RTP lifetime to 316.0 ms with an excellent phosphorescence quantum yield of up to 67.5% in free-standing dehydrated SPN films, representing a 340-fold improvement over the pristine hydrogels by circumventing aqueous-mediated quenching pathways. This hierarchical confinement strategy enables dynamic information processing and penetrated bioimaging applications, offering a versatile platform for designing RTP materials with tailorable photophysics.

As a pivotal advancement in energy storage technology, all-solid-state batteries represent a transformative direction for next-generation lithium-ion batteries. To address the critical challenge of low ionic conductivity in solid-state electrolytes (SSEs), we propose a machine learning-driven screening workflow to search for SSEs with high ionic conductivity. By leveraging an experimental database of lithium-ion SSEs, we trained five ensemble boosting models using exclusive elemental composition and temperature parameters. The CatBoost algorithm emerges as the optimal predictor, achieving superior accuracy in ionic conductivity estimation. By implementing this model, we systematically screened 3311 lithium-containing materials from the Materials Project database, identifying 22 promising candidates with the predicted ionic conductivity exceeding 1 mS cm⁻¹. Especially, the predicted conductivity of Li₈SeN₂ (2.72 mS cm⁻¹) is well consistent with the AIMD measurement (2.85 mS cm⁻¹). This data-driven approach accelerates SSE discovery while providing fundamental insights into structure–property relationships, establishing a robust framework for next-generation electrolyte development.

Achieving precise control over macroscopic chirality in self-organized systems is a key challenge in the development of advanced supramolecular functional materials. Here, we report a novel class of liquid crystalline compounds bearing a single chiral center, which exhibit reversible, thermally-induced helix inversion in the cholesteric phase. The (S)-naphthyl-3-hydroxypropanoic moiety is identified as the critical structural fragment responsible for this rare behavior. Remarkably, the helix inversion can be transferred from the pure chiral compound to an achiral nematic host, at guest concentrations as low as 6%, preserving the characteristic transition from a high-temperature left-handed helix to a low-temperature right-handed one. This also enables precise tuning of the helix inversion temperature across an exceptionally broad range – from below room temperature up to 114 °C. Importantly, structural modifications to the alkyl ester moiety do not suppress helix inversion, allowing for targeted tuning of inversion temperature, host compatibility, and potential incorporation of additional stimuli-responsive functions. The combination of thermally-induced helix inversion, the ability to transfer this unique feature to an achiral host, and the wide temperature range over which this inversion can be adjusted makes these new chiral mesogens a versatile molecular platform for designing thermoresponsive chiral materials.