Materials Chemistry Frontiers最新文献

We present a combined experimental and theoretical investigation of the pressure response of the chlorine-based two-dimensional perovskite (PMA)₂PbCl₄. High-pressure synchrotron powder X-ray diffraction (HP-PXRD), photoluminescence spectroscopy (HP-PL), and density functional theory (DFT) calculations reveal that compression up to 5.45 GPa induces pronounced anisotropic lattice contraction and partial amorphization, while decompression reveals phase reversibility. The PbCl₆ octahedra remain mechanically rigid, with distortions accommodated by octahedral tilts, flattening, and migration of phenylmethylammonium cations (PMA⁺), leading to interlayer planarization and enhanced electron–phonon coupling. Elastic tensor analysis confirms moderate mechanical anisotropy and coexisting auxetic and conventional elastic responses. HP-PL demonstrates a pressure-driven crossover between narrow free-exciton emission (quenched by 1.84 GPa) and more resilient broadband self-trapped exciton emission (persisting up to 7.8 GPa with its maximum intensity at ∼4.5 GPa). Overall, the compression-driven structure–property evolution maintains broadband emission, which leads to increased nonradiative losses at higher pressures. The combined results establish (PMA)₂PbCl₄ as a mechanically robust, pressure-tunable broadband emitter with strong potential for stable optoelectronic applications.

Compared to fluorophores, room-temperature phosphorescent (RTP) materials exhibit advantages in time-resolved imaging due to their relatively long luminescence lifetime. RTP materials circumvent interference from autofluorescence in biological tissues effectively, thereby enabling low-cost and high-resolution tumor imaging. This review summarized the mechanisms of phosphorescent radiative transitions, including key factors such as molecular orbital arrangements, spin–orbit coupling, and intermolecular interactions. The impact of chemical structures on phosphorescence quantum yield and photostability of RTP materials was emphazized. Furthermore, we reviewed recent advances in organic molecules, metal complexes and nanomaterials for tumor imaging, with a focus on the structural optimization and tumor microenvironment-responsive design. Light and X-ray as activation sources were compared for RTP materials. Finally, we proposed strategies to overcome clinical translation challenges, aiming to guide the design of RTP materials suitable for precise tumor diagnosis.

Colloidal silicon and germanium nanocrystals (Si/Ge NCs) have been of immense interest as fundamentally important semiconductor nanomaterials in the past decades due to their distinct covalent bonding characteristics, quantum-confined optoelectronic properties, high materials stability and biocompatibility. Significant advances in surface chemistry have enabled these NCs to serve as versatile material platforms where precisely engineered ligand environments control optical responses, charge transport behaviors, and device performance. This review systematically examines the evolution of surface functionalization strategies, encompassing both conventional passivation methods and innovative ligand architectures, for the property manipulation of Si/Ge NCs. The critical role of surface chemistry in enabling diverse applications, including optical devices, optoelectronic devices, and energy conversion/storage systems, is comprehensively discussed. Special attention is given to elucidating the fundamental relationships between surface chemical modifications, nanocrystal properties, and their resulting device performance.

Multi-stimuli-responsive afterglow materials have demonstrated broad applications in information encryption, anticounterfeiting, and sensors for dynamic and time-resolved emission toward various stimulus sources. Herein, through combining room-temperature phosphorescence (RTP) units with phenolic hydroxyl groups, high-temperature afterglow and acid/base-responsive properties were achieved by the formation of strong hydrogen bonding in the crystalline states and the reactivity of active hydrogen, respectively. Accordingly, the dynamic blue–green afterglow can be visible to the naked eye even at 423 K, the “turn-off” response toward HCl, and largely enhanced afterglow properties by NH₃ fumigation have been realized through the modulation of the molecular structures and aggregated states. This provided a convenient and efficient strategy to achieve multi-stimuli-responsive afterglow by the full utilization of hydroxyl groups as functional moieties.

Hydrogen sensing materials are vital for energy and environmental safety, as hydrogen's high energy density and flammability demand rapid and reliable detection at low concentrations under ambient conditions. Here, we report a palladium nanoparticle-functionalized β-ketoenamine-linked covalent organic framework (Pd@TAPT-COF) that enables efficient room-temperature hydrogen sensing. Structural analyses (solid-state ¹³C CP-MAS NMR, FTIR, and XPS) confirm successful Pd incorporation into the TAPT-COF, with characteristic shifts in CO and CN peaks evidencing strong Pd–TAPT COF interactions. The ¹³C NMR spectra show a shift in the CO peak signal from 182 ppm to 190 ppm and the appearance of a new peak at 22 ppm, confirming Pd interactions with keto carbons. FTIR showed a CO stretching shift from 1622 cm⁻¹ to 1613 cm⁻¹ and a CN shift from 1497 to 1499 cm⁻¹ after Pd doping. XPS O1s spectra exhibited distinct peaks at ∼530.8 eV (CO) and ∼532.5 eV (Pd–O), providing further evidence of Pd coordination with oxygen-containing groups. The Pd@TAPT-COF exhibited exceptional chemiresistive performance toward H₂, attaining a response (R_a/R_g) of 10, with a fast response time (T_res) of 4 s and a recovery time (T_rec) of 3 s at 1 ppm, along with superior selectivity and stability. Density functional theory (DFT) calculations support these results, revealing strong H₂ binding energies (−484.57 kJ mol⁻¹), a narrowed HOMO–LUMO gap (∼2.82 eV), increased orbital hybridization near the Fermi level, and efficient charge transfer from Pd–H interactions. These results indicate that the integration of Pd catalytic sites within the pristine TAPT-COF facilitates rapid, selective, and reversible H₂ detection, making the Pd@TAPT-COF a strong sensing material for future energy and safety sensor applications.

Two-dimensional hybrid perovskites combine the exceptional optoelectronic properties of inorganic semiconductors with the expansive diversity of organic materials. While these organic ligands offer the opportunity to introduce new functionality to tailor the properties of the hybrid, their persistence within the architecture limits the extent of modulation in response to external stimuli. Here, we show using density functional theory that 2D hybrid perovskites assembled with mixtures of organic ligands to create free volume elements within the gallery space render the hybrids amenable to intercalation by organic small molecules. Though these intercalants produce relatively small changes in the materials architecture, their presence has a pronounced effect on the optoelectronic properties of two-dimensional L₂PbI₄ perovskites. Thus, an intriguing chemical space emerges for configuring customizable responsive materials using intercalation phenomena. We can envision on that basis new technologies exploiting those traits for selective or reversible detection of organic analytes.

Viologens (1,1′-disubstituted-4,4′-bipyridinium salts) are well-known redox-active molecules with broad applications in energy conversion and optoelectronics. However, their excited-state dynamics in the solid state remain largely unexplored. Here, we report fluorescence enhancement in crystalline viologen-based organic–inorganic hybrids under continuous photoirradiation, where photoluminescence (PL) intensity increases up to sixfold relative to the initial emission within seconds of excitation. Spectroscopic studies, X-ray crystallography, and DFT calculations reveal that the phenomenon is driven by photoinduced electron transfer (PIET) from anionic donors to viologen dications, generating long-lived radicals. The radicals are confirmed via Raman and X-ray photoelectron spectroscopies and quenched by heating, which accelerates their consumption. Re-irradiation restores the PL, indicating reversibility. This PIET-driven PL enhancement is tunable by structural modification and stable across a range of temperatures and environments. The reversible optical response enables potential applications in optical memory and data storage.

Uncontrolled non-compressible hemorrhage remains a leading cause of preventable death in trauma care, underscoring the urgent need for novel hemostatic materials capable of rapid bleeding control and infection prevention under complex physiological conditions. Herein, we report the design of an injectable, water-responsive shape-memory sponge, fabricated via a dual-template strategy incorporating in situ-generated ferric tannate (TA–Fe) as a multifunctional component. The resulting hierarchically porous architecture exhibits excellent mechanical resilience, rapid shape recovery (∼6 s), and high blood uptake capacity (>4600%), enabling immediate sealing of irregular wounds. Beyond its physical hemostatic performance, TA–Fe endows the sponge with robust antibacterial activity (>99.9%), achieved through synergistic membrane disruption by phenolic hydroxyl groups, ferric ions, and photothermal effects. Moreover, TA–Fe facilitates platelet activation and fibrin network formation independent of the classical coagulation cascade, promoting accelerated thrombus formation at the bleeding site. In vivo studies using liver and arterial injury models demonstrate that PTHPFe reduces blood loss by 86% and shortens hemostatic time by 87% compared to untreated controls, significantly outperforming clinically used gelatin sponges. This hierarchically porous, shape-adaptive biomaterial offers a promising platform for next-generation hemostatic interventions, combining rapid hemorrhage control, antibacterial protection, and injectable minimal invasiveness for application in high-risk, non-compressible trauma scenarios.

Understanding structure-property relationships in ordered functional materials is essential for their rational design and optimisation. Fragment-based approaches relating materials' properties to those of their building blocks (fragments) are intuitive to chemistry and have been successfully applied in the design of metal-organic frameworks (MOFs). However, covalent organic frameworks (COFs) are resistant to such in silico fragmentation due to their covalent bonds and ambiguous definitions of nodes and linkers. Here we introduce a new algorithm, deCOFpose, designed to systematically fragment COFs into building blocks according to chemically intuitive rules, enabling fragment-based structure-property analysis, and exemplify the latter for COF band gaps. Our results reveal that the electronic features (e.g., energies of the frontier molecular orbitals) of the building blocks alone are insufficient to fully represent these materials, and the inclusion of their topological characteristics is required to engineer bespoke COFs with desired band structures.

Polydiacetylenes (PDAs), known for their distinct blue-to-red color transition, are widely applied in chemical and biological sensing, including point-of-care diagnostics. However, their high sensitivity to pH fluctuations—particularly under basic conditions—can lead to chromatic false positives, limiting reliability. In this study, we developed surfactant co-doped PDA self-assemblies that resolve this long-standing challenge by stabilizing PDA assemblies against alkaline pH while preserving their characteristic chromatic responsiveness. 10,12-Pentacosadiynoic acid (PCDA) was co-assembled with surfactants, including sodium dodecyl benzenesulfonate, sodium dodecyl sulfate, cetyltrimethylammonium bromide, Triton X-100, and Tween-20, yielding diverse morphologies such as vesicles and flower-like and rod-shaped structures, as observed by SEM and TEM. Notably, the PCDA : SDBS system formed Aloe polyphylla-like architectures and maintained remarkable chromatic stability at pH > 10, effectively addressing PDA instability in basic environments. Zeta potential analysis revealed a highly negative surface charge (–107 mV) for PCDA : SDBS, likely repelling anions from the polymer backbone and preserving chromatic integrity. Furthermore, PCDA : SDBS exhibited a selective blue-to-red transition upon interaction with the cationic surfactant CTAB. The system was further functionalized with phenyl boronic acid-modified PCDA (PDABA) for dopamine detection, achieving high selectivity and a low detection limit (1.5 ppb) under basic conditions. This co-doping strategy offers a robust route to enhance PDA stability and expand applicability in real-world sensing platforms across variable pH environments.